ref: bafc196c4b07261923d4f197659a26d0919cdeae
dir: /sys/src/libc/amd64/memcmp.s/
TEXT memcmp(SB),$0 MOVQ n+16(FP), BX CMPQ BX, $0 JEQ none MOVQ RARG, DI MOVQ p2+8(FP), SI CLD MOVQ DI, CX ORQ SI, CX ANDL $3, CX JNE c3 /* * first by longs */ MOVQ BX, CX SHRQ $2, CX REP; CMPSL JNE found /* * then by bytes */ ANDL $3, BX c3: MOVQ BX, CX REP; CMPSB JNE found1 none: MOVQ $0, AX RET /* * if long found, * back up and look by bytes */ found: MOVL $4, CX SUBQ CX, DI SUBQ CX, SI REP; CMPSB found1: JLS lt MOVQ $-1, AX RET lt: MOVQ $1, AX RET