ref: d9f3982b97f188767096902eab5ed15d2ffe73d2 dir: /sys/src/ape/lib/ap/386/strlen.s/
TEXT strlen(SB),$0 MOVL $0, AX MOVL $-1, CX CLD /* * look for end of string */ MOVL p+0(FP), DI REPN; SCASB MOVL DI, AX SUBL p+0(FP), AX SUBL $1, AX RET