ref: ad6e6444f9c1bf3a2d65c67ab8f4f48ac6468104
dir: /sys/src/libc/amd64/strcat.s/
TEXT strcat(SB),$0 MOVL $0, AX MOVQ $-1, CX CLD /* * find length of second string */ MOVQ p2+8(FP), DI REPN; SCASB MOVQ DI, BX SUBQ p2+8(FP), BX /* * find end of first string */ MOVQ RARG, DI REPN; SCASB /* * copy the memory */ SUBQ $1, 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: MOVQ BX, CX REP; MOVSB MOVQ RARG, AX RET