forked from len0rd/rockbox
143 lines
5 KiB
ArmAsm
143 lines
5 KiB
ArmAsm
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2002, 2003 Free Software Foundation, Inc.
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* This file was originally part of the GNU C Library
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* Contributed to glibc by Hartvig Ekner <hartvige@mips.com>, 2002
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* Adapted for Rockbox by Maurus Cuelenaere, 2009
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#include "config.h"
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#include "mips.h"
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/* void *memcpy(void *s1, const void *s2, size_t n); */
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#ifdef ROCKBOX_BIG_ENDIAN
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# define LWHI lwl /* high part is left in big-endian */
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# define SWHI swl /* high part is left in big-endian */
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# define LWLO lwr /* low part is right in big-endian */
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# define SWLO swr /* low part is right in big-endian */
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#else
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# define LWHI lwr /* high part is right in little-endian */
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# define SWHI swr /* high part is right in little-endian */
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# define LWLO lwl /* low part is left in little-endian */
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# define SWLO swl /* low part is left in little-endian */
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#endif
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.section .icode, "ax", %progbits
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.global memcpy
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.type memcpy, %function
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.set noreorder
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memcpy:
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slti t0, a2, 8 # Less than 8?
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bne t0, zero, last8
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move v0, a0 # Setup exit value before too late
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xor t0, a1, a0 # Find a0/a1 displacement
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andi t0, 0x3
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bne t0, zero, shift # Go handle the unaligned case
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subu t1, zero, a1
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andi t1, 0x3 # a0/a1 are aligned, but are we
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beq t1, zero, chk8w # starting in the middle of a word?
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subu a2, t1
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LWHI t0, 0(a1) # Yes we are... take care of that
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addu a1, t1
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SWHI t0, 0(a0)
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addu a0, t1
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chk8w:
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andi t0, a2, 0x1f # 32 or more bytes left?
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beq t0, a2, chk1w
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subu a3, a2, t0 # Yes
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addu a3, a1 # a3 = end address of loop
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move a2, t0 # a2 = what will be left after loop
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lop8w:
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lw t0, 0(a1) # Loop taking 8 words at a time
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lw t1, 4(a1)
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lw t2, 8(a1)
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lw t3, 12(a1)
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lw t4, 16(a1)
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lw t5, 20(a1)
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lw t6, 24(a1)
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lw t7, 28(a1)
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addiu a0, 32
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addiu a1, 32
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sw t0, -32(a0)
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sw t1, -28(a0)
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sw t2, -24(a0)
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sw t3, -20(a0)
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sw t4, -16(a0)
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sw t5, -12(a0)
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sw t6, -8(a0)
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bne a1, a3, lop8w
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sw t7, -4(a0)
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chk1w:
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andi t0, a2, 0x3 # 4 or more bytes left?
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beq t0, a2, last8
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subu a3, a2, t0 # Yes, handle them one word at a time
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addu a3, a1 # a3 again end address
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move a2, t0
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lop1w:
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lw t0, 0(a1)
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addiu a0, 4
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addiu a1, 4
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bne a1, a3, lop1w
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sw t0, -4(a0)
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last8:
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blez a2, lst8e # Handle last 8 bytes, one at a time
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addu a3, a2, a1
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lst8l:
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lb t0, 0(a1)
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addiu a0, 1
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addiu a1, 1
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bne a1, a3, lst8l
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sb t0, -1(a0)
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lst8e:
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jr ra # Bye, bye
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nop
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shift:
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subu a3, zero, a0 # Src and Dest unaligned
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andi a3, 0x3 # (unoptimized case...)
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beq a3, zero, shft1
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subu a2, a3 # a2 = bytes left
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LWHI t0, 0(a1) # Take care of first odd part
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LWLO t0, 3(a1)
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addu a1, a3
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SWHI t0, 0(a0)
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addu a0, a3
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shft1:
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andi t0, a2, 0x3
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subu a3, a2, t0
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addu a3, a1
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shfth:
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LWHI t1, 0(a1) # Limp through, word by word
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LWLO t1, 3(a1)
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addiu a0, 4
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addiu a1, 4
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bne a1, a3, shfth
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sw t1, -4(a0)
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b last8 # Handle anything which may be left
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move a2, t0
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.set reorder
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