178 lines
2.7 KiB
ArmAsm
178 lines
2.7 KiB
ArmAsm
! head_em.s
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.define begdat,begbss,hol0,argv,envp,_RegHp,_incptflag
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.define _Lineno,_Filna,_IgnoreMask,_TrpReg
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.sect .text
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.sect .rom
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.sect .data
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.sect .bss
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.sect .text
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.base 0x8000
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ADR R0,begbss
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ADR R1,endbss
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MOV R2,#0
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ADR R3,_incptflag
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STR R2,[R3]
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1:
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STR R2,[R0],#4
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CMP R0,R1
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BLT 1B
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! the next 2 lines are OS specific:
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SWI 16 ! OS_Getenv
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SUB R12, R1, #8 ! Get end of ram
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! R0 points to command string
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! (argv,argc) code for C
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! or Pascal file names
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MOV R9,R0 ! save pt in R0
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MOV R8,#0 ! string length
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len:
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LDR.B R7,[R9],#1
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CMP R7,#0
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ADD.NE R8,R8,#1
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BNE len
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MOV R7,R8 ! save len in R7
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! round up to multiple of 4
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ADD R8,R8,#4
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MVN R6, #3 !FFFFFFFC
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AND R8,R8,R6
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! make room on stack
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SUB R12,R12,R8 ! word aligned
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! now determine argc
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! OS intercepts blank lines, so
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! there must be at least one arg
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MOV R9,R0
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MOV R6,#0 ! holds argc
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MOV R5,#0 ! char count
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loop1:
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CMP R5,R7
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BGT next1
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LDR.B R4,[R9],#1
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ADD R5,R5,#1
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CMP R4,#32
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BEQ loop1 !skip spaces
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ADD R6,R6,#1 ! new arg
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nospace1:
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CMP R5,R7
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BGT next1
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LDR.B R4,[R9],#1
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ADD R5,R5,#1
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CMP R4,#32
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BNE nospace1
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CMP R5,R7
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BCC loop1
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! BEQ loop1
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next1:
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! store argc
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ADR R5,argc
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STR R6,[R5]
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! copy the string
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! onto the stack
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MOV R9,R0 !source
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MOV R2,R12 !dest
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MOV R3,R7 !#chars
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loop2:
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LDR.B R4,[R9],#1
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STR.B R4,[R2],#1
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SUB.S R3,R3,#1
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BNE loop2
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MOV R4, #0 ! zero terminator
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STR.B R4,[R2]
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! create space on the stack for
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! the pointers to individual args
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MOV R11, R12 ! string pt
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MOV R8,R6,LSL #2
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SUB R12,R12,R8
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! save pointer to argv[0]
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ADR R1,argv
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STR R12,[R1]
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! determine argv[0] .. argv[argc-1]
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! and store on stack
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! R11 = start of string
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! R7 = string lenth
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! R12 = stack pointer
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! R6 = argc
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MOV R9, #0 !char count
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MOV R8, #0 !arg count
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MOV R5,R11
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loop3:
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CMP R9,R7
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BGT next2
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LDR.B R4,[R5],#1
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ADD R9,R9,#1
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CMP R4,#32
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BEQ loop3
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CMP R9,R7
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BGT next2
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SUB R4,R5,#1 !compensate for incr
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STR R4,[R12,R8,LSL #2]
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ADD R8,R8,#1
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nospace2:
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CMP R9,R7
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BGT next2
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LDR.B R4,[R5],#1
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ADD R9,R9,#1
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CMP R4,#32
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BNE nospace2
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CMP R9,R7
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BCC loop3
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! BEQ loop3
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! finally, replace spaces by 0
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next2:
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MOV R5,R11 !string ptr
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MOV R6,R7 !string length
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MOV R3,#0
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loop4:
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CMP R6,#0
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BEQ next3
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LDR.B R4,[R5]
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CMP R4,#32
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STR.EQ.B R3,[R5]
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ADD R5,R5,#1
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SUB R6,R6,#1
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BAL loop4
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next3:
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ADR R11, envp
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STMFD R12<,{R11}
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ADR R11,argv
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LDR R11,[R11]
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STMFD R12<,{R11}
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ADR R11, argc
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LDR R11,[R11]
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STMFD R12<,{R11}
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BAL.L __m_a_i_n
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MOV R11,#0
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STMFD R12<,{R11}
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MOV R11,#1
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STMFD R12<,{R11}
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BAL.L _EmMon
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.sect .bss
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begbss:
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.sect .data
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begdat:
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hol0:
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.data4 0
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.data4 0
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argv:
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.data4 0
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envp:
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.data4 0
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argc:
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.data4 0
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2:
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.asciz 'PROGRAM'
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.align
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_RegHp:
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.data4 endbss
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_Lineno:
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.data4 0
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_Filna:
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.data4 0
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_IgnoreMask:
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.data4 0
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_TrpReg:
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.data4 0
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_incptflag:
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.data4 0
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