plan9fox/sys/src/libc/amd64/strcpy.s
2014-02-01 10:31:41 +01:00

41 lines
437 B
ArmAsm

TEXT strcpy(SB),$0
MOVL $0, AX
MOVQ $-1, CX
CLD
/*
* find end of second string
*/
MOVQ p2+8(FP), DI
REPN; SCASB
MOVQ DI, BX
SUBQ p2+8(FP), BX
/*
* copy the memory
*/
MOVQ RARG, DI
MOVQ p2+8(FP), SI
/*
* copy whole longs, if aligned
*/
MOVQ DI, CX
ORQ SI, CX
ANDL $3, CX
JNE c3
MOVQ BX, CX
SHRQ $2, CX
REP; MOVSL
/*
* copy the rest, by bytes
*/
ANDL $3, BX
c3:
MOVL BX, CX
REP; MOVSB
MOVQ RARG, AX
RET