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59 lines
822 B
59 lines
822 B
13 years ago
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/* $Id: memset.S,v 1.1 2000/04/14 16:49:01 mjd Exp $
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*
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* "memset" implementation of SuperH
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*
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* Copyright (C) 1999 Niibe Yutaka
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*
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*/
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/*
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* void *memset(void *s, int c, size_t n);
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*/
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.globl _memset
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.align 2
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_memset:
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tst r6,r6
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bt/s 5f ! if n=0, do nothing
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add r6,r4
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mov #12,r0
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cmp/gt r6,r0
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bt/s 4f ! if it's too small, set a byte at once
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mov r4,r0
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and #3,r0
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cmp/eq #0,r0
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bt/s 2f ! It's aligned
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sub r0,r6
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1:
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dt r0
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bf/s 1b
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mov.b r5,@-r4
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2: ! make VVVV
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extu.b r5,r5
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swap.b r5,r0 ! V0
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or r0,r5 ! VV
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swap.w r5,r0 ! VV00
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or r0,r5 ! VVVV
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!
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mov r6,r0
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shlr2 r0
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shlr r0 ! r0 = r6 >> 3
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3:
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dt r0
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mov.l r5,@-r4 ! set 8-byte at once
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bf/s 3b
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mov.l r5,@-r4
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!
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mov #7,r0
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and r0,r6
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tst r6,r6
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bt 5f
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! fill bytes
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4:
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dt r6
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bf/s 4b
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mov.b r5,@-r4
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5:
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rts
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mov r4,r0
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