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