73 lines
1.2 KiB
ArmAsm
73 lines
1.2 KiB
ArmAsm
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/*
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* Copyright (C) 2004-2006 Atmel Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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/*
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* void *memcpy(void *to, const void *from, unsigned long n)
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*
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* This implementation does word-aligned loads in the main loop,
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* possibly sacrificing alignment of stores.
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*
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* Hopefully, in most cases, both "to" and "from" will be
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* word-aligned to begin with.
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*/
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.text
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.global memcpy
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.type memcpy, @function
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memcpy:
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mov r9, r11
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andl r9, 3, COH
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brne 1f
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/* At this point, "from" is word-aligned */
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2: mov r9, r12
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5: sub r10, 4
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brlt 4f
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3: ld.w r8, r11++
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sub r10, 4
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st.w r12++, r8
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brge 3b
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4: neg r10
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reteq r9
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/* Handle unaligned count */
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lsl r10, 2
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add pc, pc, r10
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ld.ub r8, r11++
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st.b r12++, r8
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ld.ub r8, r11++
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st.b r12++, r8
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ld.ub r8, r11++
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st.b r12++, r8
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retal r9
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/* Handle unaligned "from" pointer */
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1: sub r10, 4
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movlt r9, r12
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brlt 4b
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add r10, r9
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lsl r9, 2
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add pc, pc, r9
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ld.ub r8, r11++
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st.b r12++, r8
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ld.ub r8, r11++
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st.b r12++, r8
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ld.ub r8, r11++
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st.b r12++, r8
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mov r8, r12
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add pc, pc, r9
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sub r8, 1
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nop
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sub r8, 1
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nop
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sub r8, 1
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nop
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mov r9, r8
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rjmp 5b
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