61 lines
738 B
ArmAsm
61 lines
738 B
ArmAsm
.global _memmove
|
|
.text
|
|
|
|
_memmove:
|
|
tst r6, r6
|
|
bt .zero
|
|
|
|
/* Simple optimization: if regions do not overlap, use memcpy() */
|
|
mov r4, r0
|
|
add r6, r0
|
|
cmp/ge r0, r5
|
|
bt _memmove_memcpy
|
|
mov r5, r0
|
|
add r6, r0
|
|
cmp/ge r0, r4
|
|
bt _memmove_memcpy
|
|
|
|
mov r4, r3
|
|
|
|
cmp/ge r4, r5
|
|
bf .backwards
|
|
|
|
.forwards:
|
|
/* If the destination starts before the source, copy forwards */
|
|
mov.b @r5+, r0
|
|
mov.b r0, @r4
|
|
dt r6
|
|
bf/s .forwards
|
|
add #1, r4
|
|
|
|
rts
|
|
mov r3, r0
|
|
|
|
.backwards:
|
|
/* Otherwise, copy backwards */
|
|
add r6, r4
|
|
add r6, r5
|
|
|
|
.backwards_loop:
|
|
add #-1, r5
|
|
mov.b @r5, r0
|
|
dt r6
|
|
bf/s .backwards_loop
|
|
mov.b r0, @-r4
|
|
|
|
rts
|
|
mov r3, r0
|
|
|
|
_memmove_memcpy:
|
|
mov.l .memcpy, r1
|
|
jmp @r1
|
|
nop
|
|
|
|
.zero:
|
|
rts
|
|
mov r4, r0
|
|
|
|
.align 4
|
|
.memcpy:
|
|
.long _memcpy
|