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58 lines
822 B
58 lines
822 B
/* $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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