2239aff6ab
The implementation for memory copy functions on ARM had a (disabled) provision for aligning the source pointer before loading registers with data. Turns out that aligning the _destination_ pointer is much more useful, as the read side is already sufficiently helped with the use of preload. So this changes the definition of the CALGN() macro to target the destination pointer instead, and turns it on for Feroceon processors where the gain is very noticeable. Signed-off-by: Nicolas Pitre <nico@marvell.com> Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
248 lines
5.5 KiB
ArmAsm
248 lines
5.5 KiB
ArmAsm
/*
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* linux/arch/arm/lib/copy_template.s
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*
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* Code template for optimized memory copy functions
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*
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* Author: Nicolas Pitre
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* Created: Sep 28, 2005
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* Copyright: MontaVista Software, Inc.
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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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* Theory of operation
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* -------------------
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*
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* This file provides the core code for a forward memory copy used in
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* the implementation of memcopy(), copy_to_user() and copy_from_user().
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*
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* The including file must define the following accessor macros
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* according to the need of the given function:
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*
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* ldr1w ptr reg abort
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*
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* This loads one word from 'ptr', stores it in 'reg' and increments
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* 'ptr' to the next word. The 'abort' argument is used for fixup tables.
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*
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* ldr4w ptr reg1 reg2 reg3 reg4 abort
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* ldr8w ptr, reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
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*
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* This loads four or eight words starting from 'ptr', stores them
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* in provided registers and increments 'ptr' past those words.
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* The'abort' argument is used for fixup tables.
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*
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* ldr1b ptr reg cond abort
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*
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* Similar to ldr1w, but it loads a byte and increments 'ptr' one byte.
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* It also must apply the condition code if provided, otherwise the
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* "al" condition is assumed by default.
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*
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* str1w ptr reg abort
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* str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
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* str1b ptr reg cond abort
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*
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* Same as their ldr* counterparts, but data is stored to 'ptr' location
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* rather than being loaded.
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*
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* enter reg1 reg2
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*
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* Preserve the provided registers on the stack plus any additional
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* data as needed by the implementation including this code. Called
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* upon code entry.
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*
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* exit reg1 reg2
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*
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* Restore registers with the values previously saved with the
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* 'preserv' macro. Called upon code termination.
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*/
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enter r4, lr
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subs r2, r2, #4
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blt 8f
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ands ip, r0, #3
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PLD( pld [r1, #0] )
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bne 9f
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ands ip, r1, #3
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bne 10f
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1: subs r2, r2, #(28)
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stmfd sp!, {r5 - r8}
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blt 5f
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CALGN( ands ip, r0, #31 )
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CALGN( rsb r3, ip, #32 )
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CALGN( sbcnes r4, r3, r2 ) @ C is always set here
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CALGN( bcs 2f )
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CALGN( adr r4, 6f )
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CALGN( subs r2, r2, r3 ) @ C gets set
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CALGN( add pc, r4, ip )
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PLD( pld [r1, #0] )
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2: PLD( subs r2, r2, #96 )
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PLD( pld [r1, #28] )
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PLD( blt 4f )
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PLD( pld [r1, #60] )
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PLD( pld [r1, #92] )
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3: PLD( pld [r1, #124] )
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4: ldr8w r1, r3, r4, r5, r6, r7, r8, ip, lr, abort=20f
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subs r2, r2, #32
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str8w r0, r3, r4, r5, r6, r7, r8, ip, lr, abort=20f
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bge 3b
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PLD( cmn r2, #96 )
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PLD( bge 4b )
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5: ands ip, r2, #28
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rsb ip, ip, #32
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addne pc, pc, ip @ C is always clear here
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b 7f
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6: nop
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ldr1w r1, r3, abort=20f
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ldr1w r1, r4, abort=20f
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ldr1w r1, r5, abort=20f
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ldr1w r1, r6, abort=20f
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ldr1w r1, r7, abort=20f
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ldr1w r1, r8, abort=20f
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ldr1w r1, lr, abort=20f
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add pc, pc, ip
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nop
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nop
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str1w r0, r3, abort=20f
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str1w r0, r4, abort=20f
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str1w r0, r5, abort=20f
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str1w r0, r6, abort=20f
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str1w r0, r7, abort=20f
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str1w r0, r8, abort=20f
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str1w r0, lr, abort=20f
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CALGN( bcs 2b )
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7: ldmfd sp!, {r5 - r8}
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8: movs r2, r2, lsl #31
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ldr1b r1, r3, ne, abort=21f
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ldr1b r1, r4, cs, abort=21f
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ldr1b r1, ip, cs, abort=21f
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str1b r0, r3, ne, abort=21f
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str1b r0, r4, cs, abort=21f
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str1b r0, ip, cs, abort=21f
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exit r4, pc
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9: rsb ip, ip, #4
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cmp ip, #2
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ldr1b r1, r3, gt, abort=21f
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ldr1b r1, r4, ge, abort=21f
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ldr1b r1, lr, abort=21f
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str1b r0, r3, gt, abort=21f
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str1b r0, r4, ge, abort=21f
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subs r2, r2, ip
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str1b r0, lr, abort=21f
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blt 8b
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ands ip, r1, #3
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beq 1b
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10: bic r1, r1, #3
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cmp ip, #2
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ldr1w r1, lr, abort=21f
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beq 17f
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bgt 18f
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.macro forward_copy_shift pull push
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subs r2, r2, #28
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blt 14f
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CALGN( ands ip, r0, #31 )
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CALGN( rsb ip, ip, #32 )
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CALGN( sbcnes r4, ip, r2 ) @ C is always set here
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CALGN( subcc r2, r2, ip )
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CALGN( bcc 15f )
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11: stmfd sp!, {r5 - r9}
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PLD( pld [r1, #0] )
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PLD( subs r2, r2, #96 )
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PLD( pld [r1, #28] )
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PLD( blt 13f )
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PLD( pld [r1, #60] )
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PLD( pld [r1, #92] )
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12: PLD( pld [r1, #124] )
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13: ldr4w r1, r4, r5, r6, r7, abort=19f
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mov r3, lr, pull #\pull
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subs r2, r2, #32
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ldr4w r1, r8, r9, ip, lr, abort=19f
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orr r3, r3, r4, push #\push
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mov r4, r4, pull #\pull
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orr r4, r4, r5, push #\push
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mov r5, r5, pull #\pull
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orr r5, r5, r6, push #\push
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mov r6, r6, pull #\pull
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orr r6, r6, r7, push #\push
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mov r7, r7, pull #\pull
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orr r7, r7, r8, push #\push
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mov r8, r8, pull #\pull
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orr r8, r8, r9, push #\push
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mov r9, r9, pull #\pull
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orr r9, r9, ip, push #\push
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mov ip, ip, pull #\pull
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orr ip, ip, lr, push #\push
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str8w r0, r3, r4, r5, r6, r7, r8, r9, ip, , abort=19f
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bge 12b
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PLD( cmn r2, #96 )
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PLD( bge 13b )
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ldmfd sp!, {r5 - r9}
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14: ands ip, r2, #28
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beq 16f
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15: mov r3, lr, pull #\pull
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ldr1w r1, lr, abort=21f
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subs ip, ip, #4
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orr r3, r3, lr, push #\push
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str1w r0, r3, abort=21f
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bgt 15b
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CALGN( cmp r2, #0 )
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CALGN( bge 11b )
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16: sub r1, r1, #(\push / 8)
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b 8b
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.endm
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forward_copy_shift pull=8 push=24
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17: forward_copy_shift pull=16 push=16
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18: forward_copy_shift pull=24 push=8
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/*
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* Abort preamble and completion macros.
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* If a fixup handler is required then those macros must surround it.
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* It is assumed that the fixup code will handle the private part of
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* the exit macro.
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*/
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.macro copy_abort_preamble
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19: ldmfd sp!, {r5 - r9}
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b 21f
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20: ldmfd sp!, {r5 - r8}
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21:
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.endm
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.macro copy_abort_end
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ldmfd sp!, {r4, pc}
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.endm
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