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