ref: 5af61e312772ca2a42c19f40cecf40e8d2c3e800 dir: /sys/src/ape/lib/ap/amd64/strlen.s/
TEXT strlen(SB),$0 MOVL $0, AX MOVQ $-1, CX CLD /* * look for end of string */ MOVQ RARG, DI REPN; SCASB MOVQ DI, AX SUBQ RARG, AX SUBQ $1, AX RET