1678 lines
52 KiB
OpenEdge ABL
1678 lines
52 KiB
OpenEdge ABL
.bp
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.AP "EM INTERPRETER"
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.nf
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.ft CW
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.lg 0
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.nr x \w' '
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.ta \nxu +\nxu +\nxu +\nxu +\nxu +\nxu +\nxu +\nxu +\nxu +\nxu
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{ This is an interpreter for EM. It serves as the official machine
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definition. This interpreter must run on a machine which supports
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arithmetic with words and memory offsets.
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Certain aspects of the definition are over specified. In particular:
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1. The representation of an address on the stack need not be the
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numerical value of the memory location.
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2. The state of the stack is not defined after a trap has aborted
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an instruction in the middle. For example, it is officially un-
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defined whether the second operand of an ADD instruction has
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been popped or not if the first one is undefined ( -32768 or
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unsigned 32768).
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3. The memory layout is implementation dependent. Only the most
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basic checks are performed whenever memory is accessed.
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4. The representation of an integer or set on the stack is not fixed
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in bit order.
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5. The format and existence of the procedure descriptors depends on
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the implementation.
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6. The result of the compare operators CMI etc. are -1, 0 and 1
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here, but other negative and positive values will do and they
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need not be the same each time.
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7. The shift count for SHL, SHR, ROL and ROR must be in the range 0
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to object size in bits - 1. The effect of a count not in this
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range is undefined.
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}
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.bp
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{$i256} {$d+}
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program em(tables,prog,input,output);
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label 8888,9999;
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const
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t15 = 32768; { 2**15 }
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t15m1 = 32767; { 2**15 -1 }
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t16 = 65536; { 2**16 }
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t16m1 = 65535; { 2**16 -1 }
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t31m1 = 2147483647; { 2**31 -1 }
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wsize = 2; { number of bytes in a word }
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asize = 2; { number of bytes in an address }
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fsize = 4; { number of bytes in a floating point number }
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maxret =4; { number of words in the return value area }
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signbit = t15; { the power of two indicating the sign bit }
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negoff = t16; { the next power of two }
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maxsint = t15m1; { the maximum signed integer }
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maxuint = t16m1; { the maximum unsigned integer }
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maxdbl = t31m1; { the maximum double signed integer }
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maxadr = t16m1; { the maximum address }
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maxoffs = t15m1; { the maximum offset from an address }
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maxbitnr= 15; { the number of the highest bit }
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lineadr = 0; { address of the line number }
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fileadr = 4; { address of the file name }
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maxcode = 8191; { highest byte in code address space }
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maxdata = 8191; { highest byte in data address space }
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{ format of status save area }
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statd = 4; { how far is static link from lb }
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dynd = 2; { how far is dynamic link from lb }
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reta = 0; { how far is the return address from lb }
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savsize = 4; { size of save area in bytes }
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{ procedure descriptor format }
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pdlocs = 0; { offset for size of local variables in bytes }
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pdbase = asize; { offset for the procedure base }
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pdsize = 4; { size of procedure descriptor in bytes = 2*asize }
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{ header words }
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NTEXT = 1;
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NDATA = 2;
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NPROC = 3;
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ENTRY = 4;
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NLINE = 5;
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SZDATA = 6;
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escape1 = 254; { escape to secondary opcodes }
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escape2 = 255; { escape to tertiary opcodes }
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undef = signbit; { the range of integers is -32767 to +32767 }
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{ error codes }
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EARRAY = 0; ERANGE = 1; ESET = 2; EIOVFL = 3; EFOVFL = 4;
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EFUNFL = 5; EIDIVZ = 6; EFDIVZ = 7; EIUND = 8; EFUND = 9;
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ECONV = 10; ESTACK = 16; EHEAP = 17; EILLINS = 18; EODDZ = 19;
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ECASE = 20; EMEMFLT = 21; EBADPTR = 22; EBADPC = 23; EBADLAE = 24;
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EBADMON = 25; EBADLIN = 26; EBADGTO = 27;
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.ne 20
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.bp
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{---------------------------------------------------------------------------}
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{ Declarations }
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{---------------------------------------------------------------------------}
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type
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bitval= 0..1; { one bit }
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bitnr= 0..maxbitnr; { bits in machine words are numbered 0 to 15 }
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byte= 0..255; { memory is an array of bytes }
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adr= {0..maxadr} long; { the range of addresses }
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word= {0..maxuint} long;{ the range of unsigned integers }
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offs= -maxoffs..maxoffs; { the range of signed offsets from addresses }
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size= 0..maxoffs; { the range of sizes is the positive offsets }
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sword= {-signbit..maxsint} long; { the range of signed integers }
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full= {-maxuint..maxuint} long; { intermediate results need this range }
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double={-maxdbl..maxdbl} long; { double precision range }
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bftype= (andf,iorf,xorf); { tells which boolean operator needed }
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insclass=(prim,second,tert); { tells which opcode table is in use }
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instype=(implic,explic); { does opcode have implicit or explicit operand }
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iflags= (mini,short,sbit,wbit,zbit,ibit);
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ifset= set of iflags;
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mnem = ( NON,
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AAR, ADF, ADI, ADP, ADS, ADU,XAND, ASP, ASS, BEQ,
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BGE, BGT, BLE, BLM, BLS, BLT, BNE, BRA, CAI, CAL,
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CFF, CFI, CFU, CIF, CII, CIU, CMF, CMI, CMP, CMS,
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CMU, COM, CSA, CSB, CUF, CUI, CUU, DCH, DEC, DEE,
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DEL, DUP, DUS, DVF, DVI, DVU, EXG, FEF, FIF, FIL,
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GTO, INC, INE, INL, INN, IOR, LAE, LAL, LAR, LDC,
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LDE, LDF, LDL, LFR, LIL, LIM, LIN, LNI, LOC, LOE,
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LOF, LOI, LOL, LOR, LOS, LPB, LPI, LXA, LXL, MLF,
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MLI, MLU, MON, NGF, NGI, NOP, RCK, RET, RMI, RMU,
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ROL, ROR, RTT, SAR, SBF, SBI, SBS, SBU, SDE, SDF,
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SDL,XSET, SIG, SIL, SIM, SLI, SLU, SRI, SRU, STE,
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STF, STI, STL, STR, STS, TEQ, TGE, TGT, TLE, TLT,
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TNE, TRP, XOR, ZEQ, ZER, ZGE, ZGT, ZLE, ZLT, ZNE,
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ZRE, ZRF, ZRL);
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dispatch = record
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iflag: ifset;
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instr: mnem;
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case instype of
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implic: (implicit:sword);
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explic: (ilength:byte);
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end;
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var
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code: packed array[0..maxcode] of byte; { code space }
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data: packed array[0..maxdata] of byte; { data space }
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retarea: array[1..maxret ] of word; { return area }
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pc,lb,sp,hp,pd: adr; { internal machine registers }
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i: integer; { integer scratch variable }
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s,t :word; { scratch variables }
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sz:size; { scratch variables }
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ss,st: sword; { scratch variables }
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k :double; { scratch variables }
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j:size; { scratch variable used as index }
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a,b:adr; { scratch variable used for addresses }
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dt,ds:double; { scratch variables for double precision }
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rt,rs,x,y:real; { scratch variables for real }
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found:boolean; { scratch }
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opcode: byte; { holds the opcode during execution }
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iclass: insclass; { true for escaped opcodes }
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dispat: array[insclass,byte] of dispatch;
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retsize:size; { holds size of last LFR }
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insr: mnem; { holds the instruction number }
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halted: boolean; { normally false }
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exitstatus:word; { parameter of MON 1 }
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ignmask:word; { ignore mask for traps }
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uerrorproc:adr; { number of user defined error procedure }
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intrap:boolean; { Set when executing trap(), to catch recursive calls}
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trapval:byte; { Set to number of last trap }
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header: array[1..8] of adr;
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tables: text; { description of EM instructions }
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prog: file of byte; { program and initialized data }
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.ne 20
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.sp 2
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{---------------------------------------------------------------------------}
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{ Various check routines }
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{---------------------------------------------------------------------------}
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{ Only the most basic checks are performed. These routines are inherently
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implementation dependent. }
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procedure trap(n:byte); forward;
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procedure memadr(a:adr);
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begin if (a>maxdata) or ((a<sp) and (a>=hp)) then trap(EMEMFLT) end;
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procedure wordadr(a:adr);
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begin memadr(a); if (a mod wsize<>0) then trap(EBADPTR) end;
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procedure chkadr(a:adr; s:size);
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begin memadr(a); memadr(a+s-1); { assumption: size is ok }
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if s<wsize
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then begin if a mod s<>0 then trap(EBADPTR) end
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else if a mod wsize<>0 then trap(EBADPTR)
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end;
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procedure newpc(a:double);
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begin if (a<0) or (a>maxcode) then trap(EBADPC); pc:=a end;
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procedure newsp(a:adr);
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begin if (a>lb) or (a<hp) or (a mod wsize<>0) then trap(ESTACK); sp:=a end;
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procedure newlb(a:adr);
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begin if (a<sp) or (a mod wsize<>0) then trap(ESTACK); lb:=a end;
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procedure newhp(a:adr);
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begin if (a>sp) or (a>maxdata+1) or (a mod wsize<>0)
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then trap(EHEAP)
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else hp:=a
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end;
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function argc(a:double):sword;
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begin if (a<-signbit) or (a>maxsint) then trap(EILLINS); argc:=a end;
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function argd(a:double):double;
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begin if (a<-maxdbl) or (a>maxdbl) then trap(EILLINS); argd:=a end;
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function argl(a:double):offs;
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begin if (a<-maxoffs) or (a>maxoffs) then trap(EILLINS); argl:=a end;
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function argg(k:double):adr;
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begin if (k<0) or (k>maxadr) then trap(EILLINS); argg:=k end;
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function argf(a:double):offs;
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begin if (a<-maxoffs) or (a>maxoffs) then trap(EILLINS); argf:=a end;
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function argn(a:double):word;
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begin if (a<0) or (a>maxuint) then trap(EILLINS); argn:=a end;
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function args(a:double):size;
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begin if (a<=0) or (a>maxoffs)
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then trap(EODDZ)
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else if (a mod wsize)<>0 then trap(EODDZ);
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args:=a ;
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end;
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function argz(a:double):size;
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begin if (a<0) or (a>maxoffs)
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then trap(EODDZ)
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else if (a mod wsize)<>0 then trap(EODDZ);
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argz:=a ;
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end;
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function argo(a:double):size;
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begin if (a<=0) or (a>maxoffs)
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then trap(EODDZ)
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else if (a mod wsize<>0) and (wsize mod a<>0) then trap(EODDZ);
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argo:=a ;
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end;
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function argw(a:double):size;
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begin if (a<=0) or (a>maxoffs) or (a>maxuint)
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then trap(EODDZ)
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else if (a mod wsize)<>0 then trap(EODDZ);
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argw:=a ;
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end;
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function argp(a:double):size;
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begin if (a<0) or (a>=header[NPROC]) then trap(EILLINS); argp:=a end;
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function argr(a:double):word;
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begin if (a<0) or (a>2) then trap(EILLINS); argr:=a end;
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procedure argwf(s:double);
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begin if argw(s)<>fsize then trap(EILLINS) end;
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function szindex(s:double):integer;
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begin s:=argw(s); if (s mod wsize <> 0) or (s>2*wsize) then trap(EILLINS);
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szindex:=s div wsize
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end;
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function locadr(l:double):adr;
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begin l:=argl(l); if l<0 then locadr:=lb+l else locadr:=lb+l+savsize end;
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function signwd(w:word):sword;
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begin if w = undef then trap(EIUND);
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if w >= signbit then signwd:=w-negoff else signwd:=w
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end;
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function dosign(w:word):sword;
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begin if w >= signbit then dosign:=w-negoff else dosign:=w end;
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function unsign(w:sword):word;
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begin if w<0 then unsign:=w+negoff else unsign:=w end;
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function chopw(dw:double):word;
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begin chopw:=dw mod negoff end;
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function fitsw(w:full;trapno:byte):word;
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{ checks whether value fits in signed word, returns unsigned representation}
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begin
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if (w>maxsint) or (w<-signbit) then
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begin trap(trapno);
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if w<0 then fitsw:=negoff- (-w)mod negoff
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else fitsw:=w mod negoff;
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end
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else fitsw:=unsign(w)
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end;
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function fitd(w:full):double;
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begin
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if abs(w) > maxdbl then trap(ECONV);
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fitd:=w
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end;
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.ne 20
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.sp 2
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{---------------------------------------------------------------------------}
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{ Memory access routines }
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{---------------------------------------------------------------------------}
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{ memw returns a machine word as an unsigned integer
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memb returns a single byte as a positive integer: 0 <= memb <= 255
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mems(a,s) fetches an object smaller than a word and returns a word
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store(a,v) stores the word v at machine address a
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storea(a,v) stores the address v at machine address a
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storeb(a,b) stores the byte b at machine address a
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stores(a,s,v) stores the s least significant bytes of a word at address a
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memi returns an offset from the instruction space
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Note that the procedure descriptors are part of instruction space.
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nextpc returns the next byte addressed by pc, incrementing pc
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lino changes the line number word.
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filna changes the pointer to the file name.
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All routines check to make sure the address is within range and valid for
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the size of the object. If an addressing error is found, a trap occurs.
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}
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function memw(a:adr):word;
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var b:word; i:integer;
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begin wordadr(a); b:=0;
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for i:=wsize-1 downto 0 do b:=256*b + data[a+i] ;
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memw:=b
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end;
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function memd(a:adr):double; { Always signed }
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var b:double; i:integer;
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begin wordadr(a); b:=data[a+2*wsize-1];
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if b>=128 then b:=b-256;
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for i:=2*wsize-2 downto 0 do b:=256*b + data[a+i] ;
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memd:=b
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end;
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function mema(a:adr):adr;
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var b:adr; i:integer;
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begin wordadr(a); b:=0;
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for i:=asize-1 downto 0 do b:=256*b + data[a+i] ;
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mema:=b
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end;
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function mems(a:adr;s:size):word;
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var i:integer; b:word;
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begin chkadr(a,s); b:=0; for i:=1 to s do b:=b*256+data[a+s-i]; mems:=b end;
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function memb(a:adr):byte;
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begin memadr(a); memb:=data[a] end;
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procedure store(a:adr; x:word);
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var i:integer;
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begin wordadr(a);
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for i:=0 to wsize-1 do
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begin data[a+i]:=x mod 256; x:=x div 256 end
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end;
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procedure storea(a:adr; x:adr);
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var i:integer;
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begin wordadr(a);
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for i:=0 to asize-1 do
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begin data[a+i]:=x mod 256; x:=x div 256 end
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end;
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procedure stores(a:adr;s:size;v:word);
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var i:integer;
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begin chkadr(a,s);
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for i:=0 to s-1 do begin data[a+i]:=v mod 256; v:=v div 256 end;
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end;
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procedure storeb(a:adr; b:byte);
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begin memadr(a); data[a]:=b end;
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function memi(a:adr):adr;
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var b:adr; i:integer;
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begin if (a mod wsize<>0) or (a+asize-1>maxcode) then trap(EBADPTR); b:=0;
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for i:=asize-1 downto 0 do b:=256*b + code[a+i] ;
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memi:=b
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end;
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function nextpc:byte;
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begin if pc>=pd then trap(EBADPC); nextpc:=code[pc]; newpc(pc+1) end;
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procedure lino(w:word);
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begin store(lineadr,w) end;
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procedure filna(a:adr);
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begin storea(fileadr,a) end;
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.ne 20
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.sp 2
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{---------------------------------------------------------------------------}
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{ Stack Manipulation Routines }
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{---------------------------------------------------------------------------}
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{ push puts a word on the stack
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pushsw takes a signed one word integer and pushes it on the stack
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pop removes a machine word from the stack and delivers it as a word
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popsw removes a machine word from the stack and delivers a signed integer
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pusha pushes an address on the stack
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popa removes a machine word from the stack and delivers it as an address
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pushd pushes a double precision number on the stack
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popd removes two machine words and returns a double precision integer
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pushr pushes a float (floating point) number on the stack
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popr removes several machine words and returns a float number
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pushx puts an object of arbitrary size on the stack
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popx removes an object of arbitrary size
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}
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procedure push(x:word);
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begin newsp(sp-wsize); store(sp,x) end;
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procedure pushsw(x:sword);
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begin newsp(sp-wsize); store(sp,unsign(x)) end;
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function pop:word;
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begin pop:=memw(sp); newsp(sp+wsize) end;
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function popsw:sword;
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begin popsw:=signwd(pop) end;
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procedure pusha(x:adr);
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begin newsp(sp-asize); storea(sp,x) end;
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function popa:adr;
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begin popa:=mema(sp); newsp(sp+asize) end;
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procedure pushd(y:double);
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begin { push double integer onto the stack } newsp(sp-2*wsize) end;
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function popd:double;
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begin { pop double integer from the stack } newsp(sp+2*wsize); popd:=0 end;
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procedure pushr(z:real);
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begin { Push a float onto the stack } newsp(sp-fsize) end;
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function popr:real;
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begin { pop float from the stack } newsp(sp+fsize); popr:=0.0 end;
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procedure pushx(objsize:size; a:adr);
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var i:integer;
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begin
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if objsize<wsize
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then push(mems(a,objsize))
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else for i:=1 to objsize div wsize do push(memw(a+objsize-wsize*i))
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end;
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procedure popx(objsize:size; a:adr);
|
|
var i:integer;
|
|
begin
|
|
if objsize<wsize
|
|
then stores(a,objsize,pop)
|
|
else for i:=1 to objsize div wsize do store(a-wsize+wsize*i,pop)
|
|
end;
|
|
.ne 20
|
|
.sp 2
|
|
{---------------------------------------------------------------------------}
|
|
{ Bit manipulation routines (extract, shift, rotate) }
|
|
{---------------------------------------------------------------------------}
|
|
|
|
procedure sleft(var w:sword); { 1 bit left shift }
|
|
begin w:= dosign(fitsw(2*w,EIOVFL)) end;
|
|
|
|
procedure suleft(var w:word); { 1 bit left shift }
|
|
begin w := chopw(2*w) end;
|
|
|
|
procedure sdleft(var d:double); { 1 bit left shift }
|
|
begin { shift two word signed integer } end;
|
|
|
|
procedure sright(var w:sword); { 1 bit right shift with sign extension }
|
|
begin if w >= 0 then w := w div 2 else w := (w-1) div 2 end;
|
|
|
|
procedure suright(var w:word); { 1 bit right shift without sign extension }
|
|
begin w := w div 2 end;
|
|
|
|
procedure sdright(var d:double); { 1 bit right shift }
|
|
begin { shift two word signed integer } end;
|
|
|
|
procedure rleft(var w:word); { 1 bit left rotate }
|
|
begin if w >= t15
|
|
then w:=(w-t15)*2 + 1
|
|
else w:=w*2
|
|
end;
|
|
|
|
procedure rright(var w:word); { 1 bit right rotate }
|
|
begin if w mod 2 = 1
|
|
then w:=w div 2 + t15
|
|
else w:=w div 2
|
|
end;
|
|
|
|
function sextend(w:word;s:size):word;
|
|
var i:size;
|
|
begin
|
|
for i:=1 to (wsize-s)*8 do rleft(w);
|
|
for i:=1 to (wsize-s)*8 do sright(w);
|
|
sextend:=w;
|
|
end;
|
|
|
|
function bit(b:bitnr; w:word):bitval; { return bit b of the word w }
|
|
var i:bitnr;
|
|
begin for i:= 1 to b do rright(w); bit:= w mod 2 end;
|
|
|
|
function bf(ty:bftype; w1,w2:word):word; { return boolean fcn of 2 words }
|
|
var i:bitnr; j:word;
|
|
begin j:=0;
|
|
for i:= maxbitnr downto 0 do
|
|
begin j := 2*j;
|
|
case ty of
|
|
andf: if bit(i,w1)+bit(i,w2) = 2 then j:=j+1;
|
|
iorf: if bit(i,w1)+bit(i,w2) > 0 then j:=j+1;
|
|
xorf: if bit(i,w1)+bit(i,w2) = 1 then j:=j+1
|
|
end
|
|
end;
|
|
bf:=j
|
|
end;
|
|
|
|
{---------------------------------------------------------------------------}
|
|
{ Array indexing }
|
|
{---------------------------------------------------------------------------}
|
|
|
|
function arraycalc(c:adr):adr; { subscript calculation }
|
|
var j:full; objsize:size; a:adr;
|
|
begin j:= popsw - signwd(memw(c));
|
|
if (j<0) or (j>memw(c+wsize)) then trap(EARRAY);
|
|
objsize := argo(memw(c+wsize+wsize));
|
|
a := j*objsize+popa; chkadr(a,objsize);
|
|
arraycalc:=a
|
|
end;
|
|
.ne 20
|
|
.sp 2
|
|
{---------------------------------------------------------------------------}
|
|
{ Double and Real Arithmetic }
|
|
{---------------------------------------------------------------------------}
|
|
|
|
{ All routines for doubles and floats are dummy routines, since the format of
|
|
doubles and floats is not defined in EM.
|
|
}
|
|
|
|
function doadi(ds,dt:double):double;
|
|
begin { add two doubles } doadi:=0 end;
|
|
|
|
function dosbi(ds,dt:double):double;
|
|
begin { subtract two doubles } dosbi:=0 end;
|
|
|
|
function domli(ds,dt:double):double;
|
|
begin { multiply two doubles } domli:=0 end;
|
|
|
|
function dodvi(ds,dt:double):double;
|
|
begin { divide two doubles } dodvi:=0 end;
|
|
|
|
function dormi(ds,dt:double):double;
|
|
begin { modulo of two doubles } dormi:=0 end;
|
|
|
|
function dongi(ds:double):double;
|
|
begin { negative of a double } dongi:=0 end;
|
|
|
|
function doadf(x,y:real):real;
|
|
begin { add two floats } doadf:=0.0 end;
|
|
|
|
function dosbf(x,y:real):real;
|
|
begin { subtract two floats } dosbf:=0.0 end;
|
|
|
|
function domlf(x,y:real):real;
|
|
begin { multiply two floats } domlf:=0.0 end;
|
|
|
|
function dodvf(x,y:real):real;
|
|
begin { divide two floats } dodvf:=0.0 end;
|
|
|
|
function dongf(x:real):real;
|
|
begin { negate a float } dongf:=0.0 end;
|
|
|
|
procedure dofif(x,y:real;var intpart,fraction:real);
|
|
begin { dismember x*y into integer and fractional parts }
|
|
intpart:=0.0; { integer part of x*y, same sign as x*y }
|
|
fraction:=0.0;
|
|
{ fractional part of x*y, 0<=abs(fraction)<1 and same sign as x*y }
|
|
end;
|
|
|
|
procedure dofef(x:real;var mantissa:real;var exponent:sword);
|
|
begin { dismember x into mantissa and exponent parts }
|
|
mantissa:=0.0; { mantissa of x , >= 1/2 and <1 }
|
|
exponent:=0; { base 2 exponent of x }
|
|
end;
|
|
.bp
|
|
{---------------------------------------------------------------------------}
|
|
{ Trap and Call }
|
|
{---------------------------------------------------------------------------}
|
|
|
|
procedure call(p:adr); { Perform the call }
|
|
begin
|
|
pusha(lb);pusha(pc);
|
|
newlb(sp);newsp(sp - memi(pd + pdsize*p + pdlocs));
|
|
newpc(memi(pd + pdsize*p+ pdbase))
|
|
end;
|
|
|
|
procedure dotrap(n:byte);
|
|
var i:size;
|
|
begin
|
|
if (uerrorproc=0) or intrap then
|
|
begin
|
|
if intrap then
|
|
writeln('Recursive trap, first trap number was ', trapval:1);
|
|
writeln('Error ', n:1);
|
|
writeln('With',ord(insr):4,' arg ',k:1);
|
|
goto 9999
|
|
end;
|
|
{ Deposit all interpreter variables that need to be saved on
|
|
the stack. This includes all scratch variables that can
|
|
be in use at the moment and ( not possible in this interpreter )
|
|
the internal address of the interpreter where the error occurred.
|
|
This would make it possible to execute an RTT instruction totally
|
|
transparent to the user program.
|
|
It can, for example, occur within an ADD instruction that both
|
|
operands are undefined and that the result overflows.
|
|
Although this will generate 3 error traps it must be possible
|
|
to ignore them all.
|
|
}
|
|
intrap:=true; trapval:=n;
|
|
for i:=retsize div wsize downto 1 do push(retarea[i]);
|
|
push(retsize); { saved return area }
|
|
pusha(mema(fileadr)); { saved current file name pointer }
|
|
push(memw(lineadr)); { saved line number }
|
|
push(n); { push error number }
|
|
a:=argp(uerrorproc);
|
|
uerrorproc:=0; { reset signal }
|
|
call(a); { call the routine }
|
|
intrap:=false; { Don't catch recursive traps anymore }
|
|
goto 8888; { reenter main loop }
|
|
end;
|
|
|
|
procedure trap;
|
|
{ This routine is invoked for overflow, and other run time errors.
|
|
For non-fatal errors, trap returns to the calling routine
|
|
}
|
|
begin
|
|
if n>=16 then dotrap(n) else if bit(n,ignmask)=0 then dotrap(n);
|
|
end;
|
|
|
|
procedure dortt;
|
|
{ The restoration of file address and line number is not essential.
|
|
The restoration of the return save area is.
|
|
}
|
|
var i:size;
|
|
n:word;
|
|
begin
|
|
newsp(lb); lb:=maxdata+1 ; { to circumvent ESTACK for the popa + pop }
|
|
newpc(popa); newlb(popa); { So far a plain RET 0 }
|
|
n:=pop; if (n>=16) and (n<64) then goto 9999 ;
|
|
lino(pop); filna(popa); retsize:=pop;
|
|
for i:=1 to retsize div wsize do retarea[i]:=pop ;
|
|
end;
|
|
.sp 2
|
|
{---------------------------------------------------------------------------}
|
|
{ monitor calls }
|
|
{---------------------------------------------------------------------------}
|
|
|
|
|
|
procedure domon(entry:word);
|
|
var index: 1..63;
|
|
dummy: double;
|
|
count,rwptr: adr;
|
|
token: byte;
|
|
i: integer;
|
|
begin
|
|
if (entry<=0) or (entry>63) then entry:=63 ;
|
|
index:=entry;
|
|
case index of
|
|
1: begin { exit } exitstatus:=pop; halted:=true end;
|
|
3: begin { read } dummy:=pop; { All input is from stdin }
|
|
rwptr:=popa; count:=popa;
|
|
i:=0 ;
|
|
while (not eof(input)) and (i<count) do
|
|
begin
|
|
if eoln(input) then begin storeb(rwptr,10) ; count:=i end
|
|
else storeb(rwptr,ord(input^)) ;
|
|
get(input); rwptr:=rwptr+1 ; i:=i+1 ;
|
|
end;
|
|
pusha(i); push(0)
|
|
end;
|
|
4: begin { write } dummy:=pop; { All output is to stdout }
|
|
rwptr:=popa; count:=popa;
|
|
for i:=1 to count do
|
|
begin token:=memb(rwptr); rwptr:=rwptr+1 ;
|
|
if token=10 then writeln else write(chr(token))
|
|
end ;
|
|
pusha(count);
|
|
push(0)
|
|
end;
|
|
54: begin { ioctl, faked } dummy:=popa;dummy:=popa;dummy:=pop;push(0) end ;
|
|
2, 5, 6, 7, 8, 9, 10,
|
|
11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
|
|
21, 22, 23, 24, 25, 26, 27, 28, 29, 30,
|
|
31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
|
|
41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
|
|
51, 52, 53, 55, 56, 57, 58, 59, 60,
|
|
61, 62:
|
|
begin push(22); push(22) end;
|
|
63: { exists only for the trap }
|
|
trap(EBADMON)
|
|
end
|
|
end;
|
|
.bp
|
|
{---------------------------------------------------------------------------}
|
|
{ Initialization and debugging }
|
|
{---------------------------------------------------------------------------}
|
|
|
|
procedure doident; { print line number and file name }
|
|
var a:adr; i,c:integer; found:boolean;
|
|
begin
|
|
write('at line ',memw(lineadr):1,' ');
|
|
a:=mema(fileadr); if a<>0 then
|
|
begin i:=20; found:=false;
|
|
while (i<>0) and not found do
|
|
begin c:=memb(a); a:=a+1; found:=true; i:=i-1;
|
|
if (c>=48) and (c<=57) then
|
|
begin found:=false; write(chr(ord('0')+c-48)) end;
|
|
if (c>=65) and (c<=90) then
|
|
begin found:=false; write(chr(ord('A')+c-65)) end;
|
|
if (c>=97) and (c<=122) then
|
|
begin found:=false; write(chr(ord('a')+c-97)) end;
|
|
end;
|
|
end;
|
|
writeln;
|
|
end;
|
|
|
|
procedure initialize; { start the ball rolling }
|
|
{ This is not part of the machine definition }
|
|
var cset:set of char;
|
|
f:ifset;
|
|
iclass:insclass;
|
|
insno:byte;
|
|
nops:integer;
|
|
opcode:byte;
|
|
i,j,n:integer;
|
|
wtemp:sword;
|
|
count:integer;
|
|
repc:adr;
|
|
nexta,firsta:adr;
|
|
elem:byte;
|
|
amount,ofst:size;
|
|
c:char;
|
|
|
|
function readb(n:integer):double;
|
|
var b:byte;
|
|
begin read(prog,b); if n>1 then readb:=readb(n-1)*256+b else readb:=b end;
|
|
|
|
function readbyte:byte;
|
|
begin readbyte:=readb(1) end;
|
|
|
|
function readword:word;
|
|
begin readword:=readb(wsize) end;
|
|
|
|
function readadr:adr;
|
|
begin readadr:=readb(asize) end;
|
|
|
|
function ifind(ordinal:byte):mnem;
|
|
var loopvar:mnem;
|
|
found:boolean;
|
|
begin ifind:=NON;
|
|
loopvar:=insr; found:=false;
|
|
repeat
|
|
if ordinal=ord(loopvar) then
|
|
begin found:=true; ifind:=loopvar end;
|
|
if loopvar<>ZRL then loopvar:=succ(loopvar) else loopvar:=NON;
|
|
until found or (loopvar=insr) ;
|
|
end;
|
|
|
|
procedure readhdr;
|
|
type hdrw=0..32767 ; { 16 bit header words }
|
|
var hdr: hdrw;
|
|
i: integer;
|
|
begin
|
|
for i:=0 to 7 do
|
|
begin hdr:=readb(2);
|
|
case i of
|
|
0: if hdr<>3757 then { 07255 }
|
|
begin writeln('Not an em load file'); halt end;
|
|
2: if hdr<>0 then
|
|
begin writeln('Unsolved references'); halt end;
|
|
3: if hdr<>3 then
|
|
begin writeln('Incorrect load file version'); halt end;
|
|
4: if hdr<>wsize then
|
|
begin writeln('Incorrect word size'); halt end;
|
|
5: if hdr<>asize then
|
|
begin writeln('Incorrect pointer size'); halt end;
|
|
1,6,7:;
|
|
end
|
|
end
|
|
end;
|
|
|
|
procedure noinit;
|
|
begin writeln('Illegal initialization'); halt end;
|
|
|
|
procedure readint(a:adr;s:size);
|
|
var i:size;
|
|
begin { construct integer out of byte sequence }
|
|
for i:=1 to s do { construct the value and initialize at a }
|
|
begin storeb(a,readbyte); a:=a+1 end
|
|
end;
|
|
|
|
procedure readuns(a:adr;s:size);
|
|
begin { construct unsigned out of byte sequence }
|
|
readint(a,s) { identical to readint }
|
|
end;
|
|
|
|
procedure readfloat(a:adr;s:size);
|
|
var i:size; b:byte;
|
|
begin { construct float out of string}
|
|
if (s<>4) and (s<>8) then noinit; i:=0;
|
|
repeat { eat the bytes, construct the value and intialize at a }
|
|
b:=readbyte; i:=i+1;
|
|
until b=0 ;
|
|
end;
|
|
|
|
begin
|
|
halted:=false;
|
|
exitstatus:=undef;
|
|
uerrorproc:=0; intrap:=false;
|
|
|
|
{ initialize tables }
|
|
for i:=0 to maxcode do code[i]:=0;
|
|
for i:=0 to maxdata do data[i]:=0;
|
|
for iclass:=prim to tert do
|
|
for i:=0 to 255 do
|
|
with dispat[iclass][i] do
|
|
begin instr:=NON; iflag:=[zbit] end;
|
|
|
|
{ read instruction table file. see appendix B }
|
|
{ The table read here is a simple transformation of the table on page xx }
|
|
{ - instruction names were transformed to numbers }
|
|
{ - the '-' flag was transformed to an 'i' flag for 'w' type instructions }
|
|
{ - the 'S' flag was added for instructions having signed operands }
|
|
reset(tables);
|
|
insr:=NON;
|
|
repeat
|
|
read(tables,insno) ; cset:=[]; f:=[];
|
|
insr:=ifind(insno);
|
|
if insr=NON then begin writeln('Incorrect table'); halt end;
|
|
repeat read(tables,c) until c<>' ' ;
|
|
repeat
|
|
cset:=cset+[c];
|
|
read(tables,c)
|
|
until c=' ' ;
|
|
if 'm' in cset then f:=f+[mini];
|
|
if 's' in cset then f:=f+[short];
|
|
if '-' in cset then f:=f+[zbit];
|
|
if 'i' in cset then f:=f+[ibit];
|
|
if 'S' in cset then f:=f+[sbit];
|
|
if 'w' in cset then f:=f+[wbit];
|
|
if (mini in f) or (short in f) then read(tables,nops) else nops:=1 ;
|
|
readln(tables,opcode);
|
|
if ('4' in cset) or ('8' in cset) then
|
|
begin iclass:=tert end
|
|
else if 'e' in cset then
|
|
begin iclass:=second end
|
|
else iclass:=prim;
|
|
for i:=0 to nops-1 do
|
|
begin
|
|
with dispat[iclass,opcode+i] do
|
|
begin
|
|
iflag:=f; instr:=insr;
|
|
if '2' in cset then ilength:=2
|
|
else if 'u' in cset then ilength:=2
|
|
else if '4' in cset then ilength:=4
|
|
else if '8' in cset then ilength:=8
|
|
else if (mini in f) or (short in f) then
|
|
begin
|
|
if 'N' in cset then wtemp:=-1-i else wtemp:=i ;
|
|
if 'o' in cset then wtemp:=wtemp+1 ;
|
|
if short in f then wtemp:=wtemp*256 ;
|
|
implicit:=wtemp
|
|
end
|
|
end
|
|
end
|
|
until eof(tables);
|
|
|
|
{ read in program text, data and procedure descriptors }
|
|
reset(prog);
|
|
readhdr; { verify first header }
|
|
for i:=1 to 8 do header[i]:=readadr; { read second header }
|
|
hp:=maxdata+1; sp:=maxdata+1; lino(0);
|
|
{ read program text }
|
|
if header[NTEXT]+header[NPROC]*pdsize>maxcode then
|
|
begin writeln('Text size too large'); halt end;
|
|
if header[SZDATA]>maxdata then
|
|
begin writeln('Data size too large'); halt end;
|
|
for i:=0 to header[NTEXT]-1 do code[i]:=readbyte;
|
|
{ read data blocks }
|
|
nexta:=0;
|
|
for i:=1 to header[NDATA] do
|
|
begin
|
|
n:=readbyte;
|
|
if n<>0 then
|
|
begin
|
|
elem:=readbyte; firsta:=nexta;
|
|
case n of
|
|
1: { uninitialized words }
|
|
for j:=1 to elem do
|
|
begin store(nexta,undef); nexta:=nexta+wsize end;
|
|
2: { initialized bytes }
|
|
for j:=1 to elem do
|
|
begin storeb(nexta,readbyte); nexta:=nexta+1 end;
|
|
3: { initialized words }
|
|
for j:=1 to elem do
|
|
begin store(nexta,readword); nexta:=nexta+wsize end;
|
|
4,5: { instruction and data pointers }
|
|
for j:=1 to elem do
|
|
begin storea(nexta,readadr); nexta:=nexta+asize end;
|
|
6: { signed integers }
|
|
begin readint(nexta,elem); nexta:=nexta+elem end;
|
|
7: { unsigned integers }
|
|
begin readuns(nexta,elem); nexta:=nexta+elem end;
|
|
8: { floating point numbers }
|
|
begin readfloat(nexta,elem); nexta:=nexta+elem end;
|
|
end
|
|
end
|
|
else
|
|
begin
|
|
repc:=readadr; amount:=nexta-firsta;
|
|
for count:=1 to repc do
|
|
begin
|
|
for ofst:=0 to amount-1 do data[nexta+ofst]:=data[firsta+ofst];
|
|
nexta:=nexta+amount;
|
|
end
|
|
end
|
|
end;
|
|
if header[SZDATA]<>nexta then writeln('Data initialization error');
|
|
hp:=nexta;
|
|
{ read descriptor table }
|
|
pd:=header[NTEXT];
|
|
for i:=1 to header[NPROC]*pdsize do code[pd+i-1]:=readbyte;
|
|
{ call the entry point routine }
|
|
ignmask:=0; { catch all traps, higher numbered traps cannot be ignored}
|
|
retsize:=0;
|
|
lb:=maxdata; { illegal dynamic link }
|
|
pc:=maxcode; { illegal return address }
|
|
push(0); a:=sp; { No environment }
|
|
push(0); b:=sp; { No args }
|
|
pusha(a); { envp }
|
|
pusha(b); { argv }
|
|
push(0); { argc }
|
|
call(argp(header[ENTRY]));
|
|
end;
|
|
.bp
|
|
{---------------------------------------------------------------------------}
|
|
{ MAIN LOOP OF THE INTERPRETER }
|
|
{---------------------------------------------------------------------------}
|
|
{ It should be noted that the interpreter (microprogram) for an EM
|
|
machine can be written in two fundamentally different ways: (1) the
|
|
instruction operands are fetched in the main loop, or (2) the in-
|
|
struction operands are fetched after the 256 way branch, by the exe-
|
|
cution routines themselves. In this interpreter, method (1) is used
|
|
to simplify the description of execution routines. The dispatch
|
|
table dispat is used to determine how the operand is encoded. There
|
|
are 4 possibilities:
|
|
|
|
0. There is no operand
|
|
1. The operand and instruction are together in 1 byte (mini)
|
|
2. The operand is one byte long and follows the opcode byte(s)
|
|
3. The operand is two bytes long and follows the opcode byte(s)
|
|
4. The operand is four bytes long and follows the opcode byte(s)
|
|
|
|
In this interpreter, the main loop determines the operand type,
|
|
fetches it, and leaves it in the global variable k for the execution
|
|
routines to use. Consequently, instructions such as LOL, which use
|
|
three different formats, need only be described once in the body of
|
|
the interpreter.
|
|
However, for a production interpreter, or a hardware EM
|
|
machine, it is probably better to use method (2), i.e. to let the
|
|
execution routines themselves fetch their own operands. The reason
|
|
for this is that each opcode uniquely determines the operand format,
|
|
so no table lookup in the dispatch table is needed. The whole table
|
|
is not needed. Method (2) therefore executes much faster.
|
|
However, separate execution routines will be needed for LOL with
|
|
a one byte offset, and LOL with a two byte offset. It is to avoid
|
|
this additional clutter that method (1) is used here. In a produc-
|
|
tion interpreter, it is envisioned that the main loop will fetch the
|
|
next instruction byte, and use it as an index into a 256 word table
|
|
to find the address of the interpreter routine to jump to. The
|
|
routine jumped to will begin by fetching its operand, if any,
|
|
without any table lookup, since it knows which format to expect.
|
|
After doing the work, it returns to the main loop by jumping in-
|
|
directly to a register that contains the address of the main loop.
|
|
A slight variation on this idea is to have the register contain
|
|
the address of the branch table, rather than the address of the main
|
|
loop.
|
|
Another issue is whether the execution routines for LOL 0, LOL
|
|
2, LOL 4, etc. should all be have distinct execution routines. Doing
|
|
so provides for the maximum speed, since the operand is implicit in
|
|
the routine itself. The disadvantage is that many nearly identical
|
|
execution routines will then be needed. Another way of doing it is
|
|
to keep the instruction byte fetched from memory (LOL 0, LOL 2, LOL
|
|
4, etc.) in some register, and have all the LOL mini format instruc-
|
|
tions branch to a common routine. This routine can then determine
|
|
the operand by subtracting the code for LOL 0 from the register,
|
|
leaving the true operand in the register (as a word quantity of
|
|
course). This method makes the interpreter smaller, but is a bit
|
|
slower.
|
|
.bp
|
|
To make this important point a little clearer, consider how a
|
|
production interpreter for the PDP-11 might appear. Let us assume the
|
|
following opcodes have been assigned:
|
|
|
|
31: LOL -2 (2 bytes, i.e. next word)
|
|
32: LOL -4
|
|
33: LOL -6
|
|
34: LOL b (format with a one byte offset)
|
|
35: LOL w (format with a one word, i.e. two byte offset)
|
|
|
|
Further assume that each of the 5 opcodes will have its own execution
|
|
routine, i.e. we are making a tradeoff in favor of fast execution and
|
|
a slightly larger interpreter.
|
|
Register r5 is the em program counter.
|
|
Register r4 is the em LB register
|
|
Register r3 is the em SP register (the stack grows toward low core)
|
|
Register r2 contains the interpreter address of the main loop
|
|
|
|
The main loop looks like this:
|
|
|
|
movb (r5)+,r0 /fetch the opcode into r0 and increment r5
|
|
asl r0 /shift r0 left 1 bit. Now: -256<=r0<=+254
|
|
jmp *table(r0) /jump to execution routine
|
|
|
|
Notice that no operand fetching has been done. The execution routines for
|
|
the 5 sample instructions given above might be as follows:
|
|
|
|
lol2: mov -2(r4),-(sp) /push local -2 onto stack
|
|
jmp (r2) /go back to main loop
|
|
lol4: mov -4(r4),-(sp) /push local -4 onto stack
|
|
jmp (r2) /go back to main loop
|
|
lol6: mov -6(r4),-(sp) /push local -6 onto stack
|
|
jmp (r2) /go back to main loop
|
|
lolb: mov $177400,r0 /prepare to fetch the 1 byte operand
|
|
bisb (r5)+,r0 /operand is now in r0
|
|
asl r0 /r0 is now offset from LB in bytes, not words
|
|
add r4,r0 /r0 is now address of the needed local
|
|
mov (r0),-(sp) /push the local onto the stack
|
|
jmp (r2)
|
|
lolw: clr r0 /prepare to fetch the 2 byte operand
|
|
bisb (r5)+,r0 /fetch high order byte first !!!
|
|
swab r0 /insert high order byte in place
|
|
bisb (r5)+,r0 /insert low order byte in place
|
|
asl r0 /convert offset to bytes, from words
|
|
add r4,r0 /r0 is now address of needed local
|
|
mov (r0),-(sp) /stack the local
|
|
jmp (r2) /done
|
|
|
|
The important thing to notice is where and how the operand fetch occurred:
|
|
lol2, lol4, and lol6, (the mini's) have implicit operands
|
|
lolb knew it had to fetch one byte, and did so without any table lookup
|
|
lolw knew it had to fetch a word, and did so, high order byte first }
|
|
.bp
|
|
.sp 4
|
|
{---------------------------------------------------------------------------}
|
|
{ Routines for the individual instructions }
|
|
{---------------------------------------------------------------------------}
|
|
procedure loadops;
|
|
var j:integer;
|
|
begin
|
|
case insr of
|
|
{ LOAD GROUP }
|
|
LDC: pushd(argd(k));
|
|
LOC: pushsw(argc(k));
|
|
LOL: push(memw(locadr(k)));
|
|
LOE: push(memw(argg(k)));
|
|
LIL: push(memw(mema(locadr(k))));
|
|
LOF: push(memw(popa+argf(k)));
|
|
LAL: pusha(locadr(k));
|
|
LAE: pusha(argg(k));
|
|
LXL: begin a:=lb; for j:=1 to argn(k) do a:=mema(a+savsize); pusha(a) end;
|
|
LXA: begin a:=lb;
|
|
for j:=1 to argn(k) do a:= mema(a+savsize);
|
|
pusha(a+savsize)
|
|
end;
|
|
LOI: pushx(argo(k),popa);
|
|
LOS: begin k:=argw(k); if k<>wsize then trap(EILLINS);
|
|
k:=pop; pushx(argo(k),popa)
|
|
end;
|
|
LDL: begin a:=locadr(k); push(memw(a+wsize)); push(memw(a)) end;
|
|
LDE: begin k:=argg(k); push(memw(k+wsize)); push(memw(k)) end;
|
|
LDF: begin k:=argf(k);
|
|
a:=popa; push(memw(a+k+wsize)); push(memw(a+k))
|
|
end;
|
|
LPI: push(argp(k))
|
|
end
|
|
end;
|
|
|
|
procedure storeops;
|
|
begin
|
|
case insr of
|
|
{ STORE GROUP }
|
|
STL: store(locadr(k),pop);
|
|
STE: store(argg(k),pop);
|
|
SIL: store(mema(locadr(k)),pop);
|
|
STF: begin a:=popa; store(a+argf(k),pop) end;
|
|
STI: popx(argo(k),popa);
|
|
STS: begin k:=argw(k); if k<>wsize then trap(EILLINS);
|
|
k:=popa; popx(argo(k),popa)
|
|
end;
|
|
SDL: begin a:=locadr(k); store(a,pop); store(a+wsize,pop) end;
|
|
SDE: begin k:=argg(k); store(k,pop); store(k+wsize,pop) end;
|
|
SDF: begin k:=argf(k); a:=popa; store(a+k,pop); store(a+k+wsize,pop) end
|
|
end
|
|
end;
|
|
|
|
procedure intarith;
|
|
var i:integer;
|
|
begin
|
|
case insr of
|
|
{ SIGNED INTEGER ARITHMETIC }
|
|
ADI: case szindex(argw(k)) of
|
|
1: begin st:=popsw; ss:=popsw; push(fitsw(ss+st,EIOVFL)) end;
|
|
2: begin dt:=popd; ds:=popd; pushd(doadi(ds,dt)) end;
|
|
end ;
|
|
SBI: case szindex(argw(k)) of
|
|
1: begin st:=popsw; ss:= popsw; push(fitsw(ss-st,EIOVFL)) end;
|
|
2: begin dt:=popd; ds:=popd; pushd(dosbi(ds,dt)) end;
|
|
end ;
|
|
MLI: case szindex(argw(k)) of
|
|
1: begin st:=popsw; ss:= popsw; push(fitsw(ss*st,EIOVFL)) end;
|
|
2: begin dt:=popd; ds:=popd; pushd(domli(ds,dt)) end;
|
|
end ;
|
|
DVI: case szindex(argw(k)) of
|
|
1: begin st:= popsw; ss:= popsw;
|
|
if st=0 then trap(EIDIVZ) else pushsw(ss div st)
|
|
end;
|
|
2: begin dt:=popd; ds:=popd; pushd(dodvi(ds,dt)) end;
|
|
end;
|
|
RMI: case szindex(argw(k)) of
|
|
1: begin st:= popsw; ss:=popsw;
|
|
if st=0 then trap(EIDIVZ) else pushsw(ss - (ss div st)*st)
|
|
end;
|
|
2: begin dt:=popd; ds:=popd; pushd(dormi(ds,dt)) end
|
|
end;
|
|
NGI: case szindex(argw(k)) of
|
|
1: begin st:=popsw; pushsw(-st) end;
|
|
2: begin ds:=popd; pushd(dongi(ds)) end
|
|
end;
|
|
SLI: begin t:=pop;
|
|
case szindex(argw(k)) of
|
|
1: begin ss:=popsw;
|
|
for i:= 1 to t do sleft(ss); pushsw(ss)
|
|
end
|
|
end
|
|
end;
|
|
SRI: begin t:=pop;
|
|
case szindex(argw(k)) of
|
|
1: begin ss:=popsw;
|
|
for i:= 1 to t do sright(ss); pushsw(ss)
|
|
end;
|
|
2: begin ds:=popd;
|
|
for i:= 1 to t do sdright(ss); pushd(ss)
|
|
end
|
|
end
|
|
end
|
|
end
|
|
end;
|
|
|
|
procedure unsarith;
|
|
var i:integer;
|
|
begin
|
|
case insr of
|
|
{ UNSIGNED INTEGER ARITHMETIC }
|
|
ADU: case szindex(argw(k)) of
|
|
1: begin t:=pop; s:= pop; push(chopw(s+t)) end;
|
|
2: trap(EILLINS);
|
|
end ;
|
|
SBU: case szindex(argw(k)) of
|
|
1: begin t:=pop; s:= pop; push(chopw(s-t)) end;
|
|
2: trap(EILLINS);
|
|
end ;
|
|
MLU: case szindex(argw(k)) of
|
|
1: begin t:=pop; s:= pop; push(chopw(s*t)) end;
|
|
2: trap(EILLINS);
|
|
end ;
|
|
DVU: case szindex(argw(k)) of
|
|
1: begin t:= pop; s:= pop;
|
|
if t=0 then trap(EIDIVZ) else push(s div t)
|
|
end;
|
|
2: trap(EILLINS);
|
|
end;
|
|
RMU: case szindex(argw(k)) of
|
|
1: begin t:= pop; s:=pop;
|
|
if t=0 then trap(EIDIVZ) else push(s - (s div t)*t)
|
|
end;
|
|
2: trap(EILLINS);
|
|
end;
|
|
SLU: case szindex(argw(k)) of
|
|
1: begin t:=pop; s:=pop;
|
|
for i:= 1 to t do suleft(s); push(s)
|
|
end;
|
|
2: trap(EILLINS);
|
|
end;
|
|
SRU: case szindex(argw(k)) of
|
|
1: begin t:=pop; s:=pop;
|
|
for i:= 1 to t do suright(s); push(s)
|
|
end;
|
|
2: trap(EILLINS);
|
|
end
|
|
end
|
|
end;
|
|
|
|
procedure fltarith;
|
|
begin
|
|
case insr of
|
|
{ FLOATING POINT ARITHMETIC }
|
|
ADF: begin argwf(k); rt:=popr; rs:=popr; pushr(doadf(rs,rt)) end;
|
|
SBF: begin argwf(k); rt:=popr; rs:=popr; pushr(dosbf(rs,rt)) end;
|
|
MLF: begin argwf(k); rt:=popr; rs:=popr; pushr(domlf(rs,rt)) end;
|
|
DVF: begin argwf(k); rt:=popr; rs:=popr; pushr(dodvf(rs,rt)) end;
|
|
NGF: begin argwf(k); rt:=popr; pushr(dongf(rt)) end;
|
|
FIF: begin argwf(k); rt:=popr; rs:=popr;
|
|
dofif(rt,rs,x,y); pushr(y); pushr(x)
|
|
end;
|
|
FEF: begin argwf(k); rt:=popr; dofef(rt,x,ss); pushr(x); pushsw(ss) end
|
|
end
|
|
end;
|
|
|
|
procedure ptrarith;
|
|
begin
|
|
case insr of
|
|
{ POINTER ARITHMETIC }
|
|
ADP: pusha(popa+argf(k));
|
|
ADS: case szindex(argw(k)) of
|
|
1: begin st:=popsw; pusha(popa+st) end;
|
|
2: begin dt:=popd; pusha(popa+dt) end;
|
|
end;
|
|
SBS: begin
|
|
a:=popa; b:=popa;
|
|
case szindex(argw(k)) of
|
|
1: push(fitsw(b-a,EIOVFL));
|
|
2: pushd(b-a)
|
|
end
|
|
end
|
|
end
|
|
end;
|
|
|
|
procedure incops;
|
|
var j:integer;
|
|
begin
|
|
case insr of
|
|
{ INCREMENT/DECREMENT/ZERO }
|
|
INC: push(fitsw(popsw+1,EIOVFL));
|
|
INL: begin a:=locadr(k); store(a,fitsw(signwd(memw(a))+1,EIOVFL)) end;
|
|
INE: begin a:=argg(k); store(a,fitsw(signwd(memw(a))+1,EIOVFL)) end;
|
|
DEC: push(fitsw(popsw-1,EIOVFL));
|
|
DEL: begin a:=locadr(k); store(a,fitsw(signwd(memw(a))-1,EIOVFL)) end;
|
|
DEE: begin a:=argg(k); store(a,fitsw(signwd(memw(a))-1,EIOVFL)) end;
|
|
ZRL: store(locadr(k),0);
|
|
ZRE: store(argg(k),0);
|
|
ZER: for j:=1 to argw(k) div wsize do push(0);
|
|
ZRF: pushr(0);
|
|
end
|
|
end;
|
|
|
|
procedure convops;
|
|
begin
|
|
case insr of
|
|
{ CONVERT GROUP }
|
|
CII: begin s:=pop; t:=pop;
|
|
if t<wsize then begin push(sextend(pop,t)); t:=wsize end;
|
|
case szindex(argw(t)) of
|
|
1: if szindex(argw(s))=2 then pushd(popsw);
|
|
2: if szindex(argw(s))=1 then push(fitsw(popd,ECONV))
|
|
end
|
|
end;
|
|
CIU: case szindex(argw(pop)) of
|
|
1: if szindex(argw(pop))=2 then push(unsign(popd mod negoff));
|
|
2: trap(EILLINS);
|
|
end;
|
|
CIF: begin argwf(pop);
|
|
case szindex(argw(pop)) of 1:pushr(popsw); 2:pushr(popd) end
|
|
end;
|
|
CUI: case szindex(argw(pop)) of
|
|
1: case szindex(argw(pop)) of
|
|
1: begin s:=pop; if s>maxsint then trap(ECONV); push(s) end;
|
|
2: trap(EILLINS);
|
|
end;
|
|
2: case szindex(argw(pop)) of
|
|
1: pushd(pop);
|
|
2: trap(EILLINS);
|
|
end;
|
|
end;
|
|
CUU: case szindex(argw(pop)) of
|
|
1: if szindex(argw(pop))=2 then trap(EILLINS);
|
|
2: trap(EILLINS);
|
|
end;
|
|
CUF: begin argwf(pop);
|
|
if szindex(argw(pop))=1 then pushr(pop) else trap(EILLINS)
|
|
end;
|
|
CFI: begin sz:=argw(pop); argwf(pop); rt:=popr;
|
|
case szindex(sz) of
|
|
1: push(fitsw(trunc(rt),ECONV));
|
|
2: pushd(fitd(trunc(rt)));
|
|
end
|
|
end;
|
|
CFU: begin sz:=argw(pop); argwf(pop); rt:=popr;
|
|
case szindex(sz) of
|
|
1: push( chopw(trunc(abs(rt)-0.5)) );
|
|
2: trap(EILLINS);
|
|
end
|
|
end;
|
|
CFF: begin argwf(pop); argwf(pop) end
|
|
end
|
|
end;
|
|
|
|
procedure logops;
|
|
var i,j:integer;
|
|
begin
|
|
case insr of
|
|
{ LOGICAL GROUP }
|
|
XAND:
|
|
begin k:=argw(k);
|
|
for j:= 1 to k div wsize do
|
|
begin a:=sp+k; t:=pop; store(a,bf(andf,memw(a),t)) end;
|
|
end;
|
|
IOR:
|
|
begin k:=argw(k);
|
|
for j:= 1 to k div wsize do
|
|
begin a:=sp+k; t:=pop; store(a,bf(iorf,memw(a),t)) end;
|
|
end;
|
|
XOR:
|
|
begin k:=argw(k);
|
|
for j:= 1 to k div wsize do
|
|
begin a:=sp+k; t:=pop; store(a,bf(xorf,memw(a),t)) end;
|
|
end;
|
|
COM:
|
|
begin k:=argw(k);
|
|
for j:= 1 to k div wsize do
|
|
begin
|
|
store(sp+k-wsize*j, bf(xorf,memw(sp+k-wsize*j), negoff-1))
|
|
end
|
|
end;
|
|
ROL: begin k:=argw(k); if k<>wsize then trap(EILLINS);
|
|
t:=pop; s:=pop; for i:= 1 to t do rleft(s); push(s)
|
|
end;
|
|
ROR: begin k:=argw(k); if k<>wsize then trap(EILLINS);
|
|
t:=pop; s:=pop; for i:= 1 to t do rright(s); push(s)
|
|
end
|
|
end
|
|
end;
|
|
|
|
procedure setops;
|
|
var i,j:integer;
|
|
begin
|
|
case insr of
|
|
{ SET GROUP }
|
|
INN:
|
|
begin k:=argw(k);
|
|
t:=pop;
|
|
i:= t mod 8; t:= t div 8;
|
|
if t>=k then
|
|
begin trap(ESET); s:=0 end
|
|
else
|
|
begin s:=memb(sp+t) end;
|
|
newsp(sp+k); push(bit(i,s));
|
|
end;
|
|
XSET:
|
|
begin k:=argw(k);
|
|
t:=pop;
|
|
i:= t mod 8; t:= t div 8;
|
|
for j:= 1 to k div wsize do push(0);
|
|
if t>=k then
|
|
trap(ESET)
|
|
else
|
|
begin s:=1; for j:= 1 to i do rleft(s); storeb(sp+t,s) end
|
|
end
|
|
end
|
|
end;
|
|
|
|
procedure arrops;
|
|
begin
|
|
case insr of
|
|
{ ARRAY GROUP }
|
|
LAR:
|
|
begin k:=argw(k); if k<>wsize then trap(EILLINS); a:=popa;
|
|
pushx(argo(memw(a+2*k)),arraycalc(a))
|
|
end;
|
|
SAR:
|
|
begin k:=argw(k); if k<>wsize then trap(EILLINS); a:=popa;
|
|
popx(argo(memw(a+2*k)),arraycalc(a))
|
|
end;
|
|
AAR:
|
|
begin k:=argw(k); if k<>wsize then trap(EILLINS); a:=popa;
|
|
push(arraycalc(a))
|
|
end
|
|
end
|
|
end;
|
|
|
|
procedure cmpops;
|
|
begin
|
|
case insr of
|
|
{ COMPARE GROUP }
|
|
CMI: case szindex(argw(k)) of
|
|
1: begin st:=popsw; ss:=popsw;
|
|
if ss<st then pushsw(-1) else if ss=st then push(0) else push(1)
|
|
end;
|
|
2: begin dt:=popd; ds:=popd;
|
|
if ds<dt then pushsw(-1) else if ds=dt then push(0) else push(1)
|
|
end;
|
|
end;
|
|
CMU: case szindex(argw(k)) of
|
|
1: begin t:=pop; s:=pop;
|
|
if s<t then pushsw(-1) else if s=t then push(0) else push(1)
|
|
end;
|
|
2: trap(EILLINS);
|
|
end;
|
|
CMP: begin a:=popa; b:=popa;
|
|
if b<a then pushsw(-1) else if b=a then push(0) else push(1)
|
|
end;
|
|
CMF: begin argwf(k); rt:=popr; rs:=popr;
|
|
if rs<rt then pushsw(-1) else if rs=rt then push(0) else push(1)
|
|
end;
|
|
CMS: begin k:=argw(k);
|
|
t:= 0; j:= 0;
|
|
while (j < k) and (t=0) do
|
|
begin if memw(sp+j) <> memw(sp+k+j) then t:=1;
|
|
j:=j+wsize
|
|
end;
|
|
newsp(sp+wsize*k); push(t);
|
|
end;
|
|
|
|
TLT: if popsw < 0 then push(1) else push(0);
|
|
TLE: if popsw <= 0 then push(1) else push(0);
|
|
TEQ: if pop = 0 then push(1) else push(0);
|
|
TNE: if pop <> 0 then push(1) else push(0);
|
|
TGE: if popsw >= 0 then push(1) else push(0);
|
|
TGT: if popsw > 0 then push(1) else push(0);
|
|
end
|
|
end;
|
|
|
|
procedure branchops;
|
|
begin
|
|
case insr of
|
|
{ BRANCH GROUP }
|
|
BRA: newpc(pc+k);
|
|
|
|
BLT: begin st:=popsw; if popsw < st then newpc(pc+k) end;
|
|
BLE: begin st:=popsw; if popsw <= st then newpc(pc+k) end;
|
|
BEQ: begin t :=pop ; if pop = t then newpc(pc+k) end;
|
|
BNE: begin t :=pop ; if pop <> t then newpc(pc+k) end;
|
|
BGE: begin st:=popsw; if popsw >= st then newpc(pc+k) end;
|
|
BGT: begin st:=popsw; if popsw > st then newpc(pc+k) end;
|
|
|
|
ZLT: if popsw < 0 then newpc(pc+k);
|
|
ZLE: if popsw <= 0 then newpc(pc+k);
|
|
ZEQ: if pop = 0 then newpc(pc+k);
|
|
ZNE: if pop <> 0 then newpc(pc+k);
|
|
ZGE: if popsw >= 0 then newpc(pc+k);
|
|
ZGT: if popsw > 0 then newpc(pc+k)
|
|
end
|
|
end;
|
|
|
|
procedure callops;
|
|
var j:integer;
|
|
begin
|
|
case insr of
|
|
{ PROCEDURE CALL GROUP }
|
|
CAL: call(argp(k));
|
|
CAI: begin call(argp(popa)) end;
|
|
RET: begin k:=argz(k); if k div wsize>maxret then trap(EILLINS);
|
|
for j:= 1 to k div wsize do retarea[j]:=pop; retsize:=k;
|
|
newsp(lb); lb:=maxdata+1; { To circumvent stack overflow error }
|
|
newpc(popa);
|
|
if pc=maxcode then
|
|
begin
|
|
halted:=true;
|
|
if retsize=wsize then exitstatus:=retarea[1]
|
|
else exitstatus:=undef
|
|
end
|
|
else
|
|
newlb(popa);
|
|
end;
|
|
LFR: begin k:=args(k); if k<>retsize then trap(EILLINS);
|
|
for j:=k div wsize downto 1 do push(retarea[j]);
|
|
end
|
|
end
|
|
end;
|
|
|
|
procedure miscops;
|
|
var i,j:integer;
|
|
begin
|
|
case insr of
|
|
{ MISCELLANEOUS GROUP }
|
|
ASP,ASS:
|
|
begin if insr=ASS then
|
|
begin k:=argw(k); if k<>wsize then trap(EILLINS); k:=popsw end;
|
|
k:=argf(k);
|
|
if k<0
|
|
then for j:= 1 to -k div wsize do push(undef)
|
|
else newsp(sp+k);
|
|
end;
|
|
BLM,BLS:
|
|
begin if insr=BLS then
|
|
begin k:=argw(k); if k<>wsize then trap(EILLINS); k:=pop end;
|
|
k:=argz(k);
|
|
b:=popa; a:=popa;
|
|
for j := 1 to k div wsize do
|
|
store(b-wsize+wsize*j,memw(a-wsize+wsize*j))
|
|
end;
|
|
CSA: begin k:=argw(k); if k<>wsize then trap(EILLINS);
|
|
a:=popa;
|
|
st:= popsw - signwd(memw(a+asize));
|
|
if (st>=0) and (st<=memw(a+wsize+asize)) then
|
|
b:=mema(a+2*wsize+asize+asize*st) else b:=mema(a);
|
|
if b=0 then trap(ECASE) else newpc(b)
|
|
end;
|
|
CSB: begin k:=argw(k); if k<>wsize then trap(EILLINS); a:=popa;
|
|
t:=pop; i:=1; found:=false;
|
|
while (i<=memw(a+asize)) and not found do
|
|
if t=memw(a+(asize+wsize)*i) then found:=true else i:=i+1;
|
|
if found then b:=memw(a+(asize+wsize)*i+wsize) else b:=memw(a);
|
|
if b=0 then trap(ECASE) else newpc(b);
|
|
end;
|
|
DCH: begin pusha(mema(popa+dynd)) end;
|
|
DUP,DUS:
|
|
begin if insr=DUS then
|
|
begin k:=argw(k); if k<>wsize then trap(EILLINS); k:=pop end;
|
|
k:=args(k);
|
|
for i:=1 to k div wsize do push(memw(sp+k-wsize));
|
|
end;
|
|
EXG: begin
|
|
k:=argw(k);
|
|
for i:=1 to k div wsize do push(memw(sp+k-wsize));
|
|
for i:=0 to k div wsize - 1 do
|
|
store(sp+k+i*wsize,memw(sp+k+k+i*wsize));
|
|
for i:=1 to k div wsize do
|
|
begin t:=pop ; store(sp+k+k-wsize,t) end;
|
|
end;
|
|
FIL: filna(argg(k));
|
|
GTO: begin k:=argg(k);
|
|
newlb(mema(k+2*asize)); newsp(mema(k+asize)); newpc(mema(k))
|
|
end;
|
|
LIM: push(ignmask);
|
|
LIN: lino(argn(k));
|
|
LNI: lino(memw(0)+1);
|
|
LOR: begin i:=argr(k);
|
|
case i of 0:pusha(lb); 1:pusha(sp); 2:pusha(hp) end;
|
|
end;
|
|
LPB: pusha(popa+statd);
|
|
MON: domon(pop);
|
|
NOP: writeln('NOP at line ',memw(0):5) ;
|
|
RCK: begin a:=popa;
|
|
case szindex(argw(k)) of
|
|
1: if (signwd(memw(sp))<signwd(memw(a))) or
|
|
(signwd(memw(sp))>signwd(memw(a+wsize))) then trap(ERANGE);
|
|
2: if (memd(sp)<memd(a)) or
|
|
(memd(sp)>memd(a+2*wsize)) then trap(ERANGE);
|
|
end
|
|
end;
|
|
RTT: dortt;
|
|
SIG: begin a:=popa; pusha(uerrorproc); uerrorproc:=a end;
|
|
SIM: ignmask:=pop;
|
|
STR: begin i:=argr(k);
|
|
case i of 0: newlb(popa); 1: newsp(popa); 2: newhp(popa) end;
|
|
end;
|
|
TRP: trap(pop)
|
|
end
|
|
end;
|
|
.bp
|
|
{---------------------------------------------------------------------------}
|
|
{ Main Loop }
|
|
{---------------------------------------------------------------------------}
|
|
|
|
begin initialize;
|
|
8888:
|
|
repeat
|
|
opcode := nextpc; { fetch the first byte of the instruction }
|
|
if opcode=escape1 then iclass:=second
|
|
else if opcode=escape2 then iclass:=tert
|
|
else iclass:=prim;
|
|
if iclass<>prim then opcode := nextpc;
|
|
with dispat[iclass][opcode] do
|
|
begin insr:=instr;
|
|
if not (zbit in iflag) then
|
|
if ibit in iflag then k:=pop else
|
|
begin
|
|
if mini in iflag then k:=implicit else
|
|
begin
|
|
if short in iflag then k:=implicit+nextpc else
|
|
begin k:=nextpc;
|
|
if (sbit in iflag) and (k>=128) then k:=k-256;
|
|
for i:=2 to ilength do k:=256*k + nextpc
|
|
end
|
|
end;
|
|
if wbit in iflag then k:=k*wsize;
|
|
end
|
|
end;
|
|
case insr of
|
|
|
|
NON: trap(EILLINS);
|
|
|
|
{ LOAD GROUP }
|
|
LDC,LOC,LOL,LOE,LIL,LOF,LAL,LAE,LXL,LXA,LOI,LOS,LDL,LDE,LDF,LPI:
|
|
loadops;
|
|
|
|
{ STORE GROUP }
|
|
STL,STE,SIL,STF,STI,STS,SDL,SDE,SDF:
|
|
storeops;
|
|
|
|
{ SIGNED INTEGER ARITHMETIC }
|
|
ADI,SBI,MLI,DVI,RMI,NGI,SLI,SRI:
|
|
intarith;
|
|
|
|
{ UNSIGNED INTEGER ARITHMETIC }
|
|
ADU,SBU,MLU,DVU,RMU,SLU,SRU:
|
|
unsarith;
|
|
|
|
{ FLOATING POINT ARITHMETIC }
|
|
ADF,SBF,MLF,DVF,NGF,FIF,FEF:
|
|
fltarith;
|
|
|
|
{ POINTER ARITHMETIC }
|
|
ADP,ADS,SBS:
|
|
ptrarith;
|
|
|
|
{ INCREMENT/DECREMENT/ZERO }
|
|
INC,INL,INE,DEC,DEL,DEE,ZRL,ZRE,ZER,ZRF:
|
|
incops;
|
|
|
|
{ CONVERT GROUP }
|
|
CII,CIU,CIF,CUI,CUU,CUF,CFI,CFU,CFF:
|
|
convops;
|
|
|
|
{ LOGICAL GROUP }
|
|
XAND,IOR,XOR,COM,ROL,ROR:
|
|
logops;
|
|
|
|
{ SET GROUP }
|
|
INN,XSET:
|
|
setops;
|
|
|
|
{ ARRAY GROUP }
|
|
LAR,SAR,AAR:
|
|
arrops;
|
|
|
|
{ COMPARE GROUP }
|
|
CMI,CMU,CMP,CMF,CMS, TLT,TLE,TEQ,TNE,TGE,TGT:
|
|
cmpops;
|
|
|
|
{ BRANCH GROUP }
|
|
BRA, BLT,BLE,BEQ,BNE,BGE,BGT, ZLT,ZLE,ZEQ,ZNE,ZGE,ZGT:
|
|
branchops;
|
|
|
|
{ PROCEDURE CALL GROUP }
|
|
CAL,CAI,RET,LFR:
|
|
callops;
|
|
|
|
{ MISCELLANEOUS GROUP }
|
|
ASP,ASS,BLM,BLS,CSA,CSB,DCH,DUP,DUS,EXG,FIL,GTO,LIM,
|
|
LIN,LNI,LOR,LPB,MON,NOP,RCK,RTT,SIG,SIM,STR,TRP:
|
|
miscops;
|
|
|
|
end; { end of case statement }
|
|
if not ( (insr=RET) or (insr=ASP) or (insr=BRA) or (insr=GTO) ) then
|
|
retsize:=0 ;
|
|
until halted;
|
|
9999:
|
|
writeln('halt with exit status: ',exitstatus:1);
|
|
doident;
|
|
end.
|
|
.ft P
|
|
.lg 1
|
|
.fi
|