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- TEXT memcpy(SB), $0
- MOVQ RARG, DI
- MOVQ DI, AX /* return value */
- MOVQ p2+8(FP), SI
- MOVL n+16(FP), BX
- CMPL BX, $0
- JGT _ok
- JEQ _return /* nothing to do if n == 0 */
- MOVL $0, SI /* fault if n < 0 */
- /*
- * check and set for backwards:
- * (p2 < p1) && ((p2+n) > p1)
- */
- _ok:
- CMPQ SI, DI
- JGT _forward
- JEQ _return /* nothing to do if p2 == p1 */
- MOVQ SI, DX
- ADDQ BX, DX
- CMPQ DX, DI
- JGT _back
- /*
- * copy whole longs if aligned
- */
- _forward:
- CLD
- MOVQ SI, DX
- ORQ DI, DX
- ANDL $3, DX
- JNE c3f
- MOVQ BX, CX
- SHRQ $2, CX
- ANDL $3, BX
- REP; MOVSL
- /*
- * copy the rest, by bytes
- */
- JEQ _return /* flags set by above ANDL */
- c3f:
- MOVL BX, CX
- REP; MOVSB
- RET
- /*
- * whole thing backwards has
- * adjusted addresses
- */
- _back:
- ADDQ BX, DI
- ADDQ BX, SI
- STD
- SUBQ $4, DI
- SUBQ $4, SI
- /*
- * copy whole longs, if aligned
- */
- MOVQ DI, DX
- ORQ SI, DX
- ANDL $3, DX
- JNE c3b
- MOVL BX, CX
- SHRQ $2, CX
- ANDL $3, BX
- REP; MOVSL
- /*
- * copy the rest, by bytes
- */
- JEQ _return /* flags set by above ANDL */
- c3b:
- ADDQ $3, DI
- ADDQ $3, SI
- MOVL BX, CX
- REP; MOVSB
- _return:
- RET
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