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.text
.syntax unified
.global memcpy
.func memcpy
.thumb_func
memcpy:
/* on entry
* r0 = targ
* r1 = src
* r2 = len (bytes)
* on exit
* r0 = targ (unchanged)
*/
push {r0, r4, lr}
/* If targ or src are unaligned, drop to byte
* processing. */
mov r3, r0
movs r4, #3
orrs r3, r1
ands r3, r4
bne L_bytewise
/* Process words */
L_wordwise:
cmp r2, #4
blo L_bytewise
ldr r4, [r1]
adds r1, #4
str r4, [r0]
adds r0, #4
subs r2, #4
b L_wordwise
/* Process bytes */
L_bytewise:
cmp r2, #0
beq L_fin
ldrb r4, [r1]
adds r1, #1
strb r4, [r0]
adds r0, #1
subs r2, #1
b L_bytewise
L_fin:
pop {r0, r4, pc}
.endfunc
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