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.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
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