Subversion Repositories openrisc_me

        .file   "strlen.S"

        .section .text

        .global  _strlen

        .type    _strlen,@function

_strlen:

        add     #0, r1, r4      ; Save a copy of the string start address and set the condition flags.

        beq     null_string     ; Test for a NULL pointer.

        mov     #-1, r3         ; Set a limit on the number of bytes examined.

        mov     #0,  r2         ; Stop searching when we find a NUL byte.

        suntil.b                ; Search until *r1 == r2

        sub     #1, r1          ; suntil.b leaves r1 pointing to the byte beyond the match.

null_string:

        sub     r4, r1          ; Compute the length.

        rts