ref: 53fbb0515159465421053c3165b1aa9da196aa4d dir: /sys/src/libc/68020/strlen.s/
TEXT strlen(SB), $0 MOVL s+0(FP), A1 TSTB (A1)+ BEQ null MOVL A1, A2 l1: TSTB (A1)+ BNE l1 SUBL A2, A1 MOVL A1, R0 RTS null: MOVL $0, R0 RTS