Re: [9fans] Hello Assembly

[erik quanstrom <quanstro@quanstro.net>]

> actually, there's probably enough space above your current location to (appear to) work, but a further error
> is hinted in the address given by the trap:
>
> 	8.out 1183: suicide: invalid address 0x7 in sys call pc=0x104e
>
> since 7 is your length value, you've also got an off-by-4 error in your stack offsets.

actually, i think there's something else wrong:

acid: asm(_main)
_main 0x00001020	SUBL	$0x18,SP
_main+0x3 0x00001023	MOVL	$0x1,0x0(SP)
_main+0xa 0x0000102a	MOVL	$string(SB),0x4(FP)
_main+0x12 0x00001032	MOVL	$0x7,0x8(FP)
_main+0x1a 0x0000103a	MOVL	$0x0,0xc(FP)
_main+0x22 0x00001042	MOVL	$0x0,0x10(FP)
_main+0x2a 0x0000104a	MOVL	$0x33,AX
_main+0x2f 0x0000104f	INTB	$0x40
_main+0x31 0x00001051	ADDL	$0x18,SP
_main+0x34 0x00001054	RET

why does the
for the equivalent c "pwrite(1, string, 7, 0)" i get this

acid: asm(main)
main 0x00001020	SUBL	$0x18,SP
main+0x3 0x00001023	MOVL	$0x1,AX
main+0x8 0x00001028	MOVL	AX,0x0(SP)
main+0xb 0x0000102b	MOVL	string(SB),AX
main+0x11 0x00001031	MOVL	AX,0x4(SP)
main+0x15 0x00001035	MOVL	$0x7,AX
main+0x1a 0x0000103a	MOVL	AX,0x8(SP)
main+0x1e 0x0000103e	MOVL	$0x0,0xc(SP)
main+0x26 0x00001046	MOVL	$0x0,0x10(SP)
main+0x2e 0x0000104e	CALL	pwrite(SB)
main+0x33 0x00001053	ADDL	$0x18,SP
main+0x36 0x00001056	RET

- erik