memcpy.S
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;;; memcpy.S
#include <asm/linkage.h>
#if defined(__H8300H__)
.h8300h
#endif
#if defined(__H8300S__)
.h8300s
#endif
.text
.global SYMBOL_NAME(memcpy)
;;; void *memcpy(void *to, void *from, size_t n)
SYMBOL_NAME_LABEL(memcpy)
mov.l er2,er2
bne 1f
rts
1:
;; address check
bld #0,r0l
bxor #0,r1l
bcs 4f
mov.l er4,@-sp
mov.l er0,@-sp
btst #0,r0l
beq 1f
;; (aligned even) odd address
mov.b @er1,r3l
mov.b r3l,@er0
adds #1,er1
adds #1,er0
dec.l #1,er2
beq 3f
1:
;; n < sizeof(unsigned long) check
sub.l er4,er4
adds #4,er4 ; loop count check value
cmp.l er4,er2
blo 2f
;; unsigned long copy
1:
mov.l @er1,er3
mov.l er3,@er0
adds #4,er0
adds #4,er1
subs #4,er2
cmp.l er4,er2
bcc 1b
;; rest
2:
mov.l er2,er2
beq 3f
1:
mov.b @er1,r3l
mov.b r3l,@er0
adds #1,er1
adds #1,er0
dec.l #1,er2
bne 1b
3:
mov.l @sp+,er0
mov.l @sp+,er4
rts
;; odd <- even / even <- odd
4:
mov.l er4,er3
mov.l er2,er4
mov.l er5,er2
mov.l er1,er5
mov.l er6,er1
mov.l er0,er6
1:
eepmov.w
mov.w r4,r4
bne 1b
dec.w #1,e4
bpl 1b
mov.l er1,er6
mov.l er2,er5
mov.l er3,er4
rts