source: trunk/libs/newlib/src/newlib/libc/machine/rx/memmove.S @ 444

        .file   "memmove.S"

        .section .text
        .global  _memmove
        .type    _memmove,@function
_memmove:
        ;; R1: DEST
        ;; R2: SRC
        ;; R3: COUNT
#ifdef __RX_DISALLOW_STRING_INSNS__
        /* Do not use the string instructions - they might prefetch
           bytes from outside of valid memory.  This is particularly
           dangerous in I/O space.  */

        cmp      #0, r3         ; If the count is zero, do nothing
        beq      4f
        
        cmp      r1, r2
        blt      3f             ; If SRC < DEST copy backwards

        mov      r1, r14        ; Save a copy of DEST

5:      mov.b    [r2+], r5
        mov.b    r5, [r14+]
        sub      #1, r3
        bne      5b
        
4:      rts

3:      add      r3, r1
        add      r3, r2

6:      mov.b    [-r2], r5
        mov.b    r5, [-r1]
        sub      #1, r3
        bne      6b

        rts
#else   
        mov     r1, r4          ; Save a copy of DEST
        cmp     r1, r2
        blt     2f              ; If SRC (r2) is less than DEST (r1) then copy backwards
        smovf
1:      
        mov     r4, r1          ; Return DEST
        rts
2:
        add     r3, r1          ; The SMOVB instructions requires the DEST in r1 and the 
        add     r3, r2          ; SRC in r2 but it needs them to point the last bytes of
        sub     #1, r2          ; the regions involved not the first bytes, hence these
        sub     #1, r1          ; additions and subtractions.
        smovb
        bra     1b

#endif /* SMOVF allowed.  */

        .size _memmove, . - _memmove