diff options
Diffstat (limited to 'sys/src/libc/amd64/memccpy.s')
| -rw-r--r-- | sys/src/libc/amd64/memccpy.s | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/sys/src/libc/amd64/memccpy.s b/sys/src/libc/amd64/memccpy.s new file mode 100644 index 000000000..d878faaf5 --- /dev/null +++ b/sys/src/libc/amd64/memccpy.s @@ -0,0 +1,58 @@ + TEXT memccpy(SB),$0 + + MOVL n+24(FP), CX + CMPL CX, $0 + JEQ none + MOVQ p2+8(FP), DI + MOVBLZX c+16(FP), AX + CLD +/* + * find the character in the second string + */ + + REPN; SCASB + JEQ found + +/* + * if not found, set count to 'n' + */ +none: + MOVL $0, AX + MOVL n+24(FP), BX + JMP memcpy + +/* + * if found, set count to bytes thru character + */ +found: + MOVQ DI, AX + SUBQ p2+8(FP), AX + MOVQ AX, BX + ADDQ RARG, AX + +/* + * copy the memory + */ + +memcpy: + MOVQ RARG, DI + MOVQ p2+8(FP), SI +/* + * copy whole longs, if aligned + */ + MOVQ DI, DX + ORQ SI, DX + ANDL $3, DX + JNE c3 + MOVL BX, CX + SHRQ $2, CX + REP; MOVSL +/* + * copy the rest, by bytes + */ + ANDL $3, BX +c3: + MOVL BX, CX + REP; MOVSB + + RET |