Commit c2563038 authored by Nicolas Pitre's avatar Nicolas Pitre Committed by Russell King
Browse files

ARM: 8285/1: remove ARMv3 user access code again 



This code was restored with commit 080fc66f ("ARM: Bring back ARMv3 IO
and user access code") because the RiscPC memory bus does not understand
half-word load/stores.  However only the IO code needed restoring since
the alternative user access code contains no half-word accesses, is
already used when CONFIG_PREEMPT is set and runs faster on a StrongARM.

Signed-off-by: default avatarNicolas Pitre <nico@linaro.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 0b7857db

arch/arm/lib/Makefile

+2 −13
Original line number Diff line number Diff line
@@ -15,19 +15,8 @@ lib-y := backtrace.o changebit.o csumipv6.o csumpartial.o \ 
		   io-readsb.o io-writesb.o io-readsl.o io-writesl.o  \

		   call_with_stack.o bswapsdi2.o



mmu-y	:= clear_user.o copy_page.o getuser.o putuser.o



# the code in uaccess.S is not preemption safe and

# probably faster on ARMv3 only

ifeq ($(CONFIG_PREEMPT),y)

  mmu-y	+= copy_from_user.o copy_to_user.o

else

ifneq ($(CONFIG_CPU_32v3),y)

  mmu-y	+= copy_from_user.o copy_to_user.o

else

  mmu-y	+= uaccess.o

endif

endif

mmu-y		:= clear_user.o copy_page.o getuser.o putuser.o       \

		   copy_from_user.o copy_to_user.o



# using lib_ here won't override already available weak symbols

obj-$(CONFIG_UACCESS_WITH_MEMCPY) += uaccess_with_memcpy.o

arch/arm/lib/uaccess.S

deleted100644 → 0
+0 −564
Original line number Diff line number Diff line 
/*

 *  linux/arch/arm/lib/uaccess.S

 *

 *  Copyright (C) 1995, 1996,1997,1998 Russell King

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 *  Routines to block copy data to/from user memory

 *   These are highly optimised both for the 4k page size

 *   and for various alignments.

 */

#include <linux/linkage.h>

#include <asm/assembler.h>

#include <asm/errno.h>

#include <asm/domain.h>



		.text



#define PAGE_SHIFT 12



/* Prototype: int __copy_to_user(void *to, const char *from, size_t n)

 * Purpose  : copy a block to user memory from kernel memory

 * Params   : to   - user memory

 *          : from - kernel memory

 *          : n    - number of bytes to copy

 * Returns  : Number of bytes NOT copied.

 */



.Lc2u_dest_not_aligned:

		rsb	ip, ip, #4

		cmp	ip, #2

		ldrb	r3, [r1], #1

USER(	TUSER(	strb)	r3, [r0], #1)			@ May fault

		ldrgeb	r3, [r1], #1

USER(	TUSER(	strgeb) r3, [r0], #1)			@ May fault

		ldrgtb	r3, [r1], #1

USER(	TUSER(	strgtb) r3, [r0], #1)			@ May fault

		sub	r2, r2, ip

		b	.Lc2u_dest_aligned



ENTRY(__copy_to_user)

		stmfd	sp!, {r2, r4 - r7, lr}

		cmp	r2, #4

		blt	.Lc2u_not_enough

		ands	ip, r0, #3

		bne	.Lc2u_dest_not_aligned

.Lc2u_dest_aligned:



		ands	ip, r1, #3

		bne	.Lc2u_src_not_aligned

/*

 * Seeing as there has to be at least 8 bytes to copy, we can

 * copy one word, and force a user-mode page fault...

 */



.Lc2u_0fupi:	subs	r2, r2, #4

		addmi	ip, r2, #4

		bmi	.Lc2u_0nowords

		ldr	r3, [r1], #4

USER(	TUSER(	str)	r3, [r0], #4)			@ May fault

		mov	ip, r0, lsl #32 - PAGE_SHIFT	@ On each page, use a ld/st??t instruction

		rsb	ip, ip, #0

		movs	ip, ip, lsr #32 - PAGE_SHIFT

		beq	.Lc2u_0fupi

/*

 * ip = max no. of bytes to copy before needing another "strt" insn

 */

		cmp	r2, ip

		movlt	ip, r2

		sub	r2, r2, ip

		subs	ip, ip, #32

		blt	.Lc2u_0rem8lp



.Lc2u_0cpy8lp:	ldmia	r1!, {r3 - r6}

		stmia	r0!, {r3 - r6}			@ Shouldnt fault

		ldmia	r1!, {r3 - r6}

		subs	ip, ip, #32

		stmia	r0!, {r3 - r6}			@ Shouldnt fault

		bpl	.Lc2u_0cpy8lp



.Lc2u_0rem8lp:	cmn	ip, #16

		ldmgeia	r1!, {r3 - r6}

		stmgeia	r0!, {r3 - r6}			@ Shouldnt fault

		tst	ip, #8

		ldmneia	r1!, {r3 - r4}

		stmneia	r0!, {r3 - r4}			@ Shouldnt fault

		tst	ip, #4

		ldrne	r3, [r1], #4

	TUSER(	strne) r3, [r0], #4			@ Shouldnt fault

		ands	ip, ip, #3

		beq	.Lc2u_0fupi

.Lc2u_0nowords:	teq	ip, #0

		beq	.Lc2u_finished

.Lc2u_nowords:	cmp	ip, #2

		ldrb	r3, [r1], #1

USER(	TUSER(	strb)	r3, [r0], #1)			@ May fault

		ldrgeb	r3, [r1], #1

USER(	TUSER(	strgeb) r3, [r0], #1)			@ May fault

		ldrgtb	r3, [r1], #1

USER(	TUSER(	strgtb) r3, [r0], #1)			@ May fault

		b	.Lc2u_finished



.Lc2u_not_enough:

		movs	ip, r2

		bne	.Lc2u_nowords

.Lc2u_finished:	mov	r0, #0

		ldmfd	sp!, {r2, r4 - r7, pc}



.Lc2u_src_not_aligned:

		bic	r1, r1, #3

		ldr	r7, [r1], #4

		cmp	ip, #2

		bgt	.Lc2u_3fupi

		beq	.Lc2u_2fupi

.Lc2u_1fupi:	subs	r2, r2, #4

		addmi	ip, r2, #4

		bmi	.Lc2u_1nowords

		mov	r3, r7, lspull #8

		ldr	r7, [r1], #4

		orr	r3, r3, r7, lspush #24

USER(	TUSER(	str)	r3, [r0], #4)			@ May fault

		mov	ip, r0, lsl #32 - PAGE_SHIFT

		rsb	ip, ip, #0

		movs	ip, ip, lsr #32 - PAGE_SHIFT

		beq	.Lc2u_1fupi

		cmp	r2, ip

		movlt	ip, r2

		sub	r2, r2, ip

		subs	ip, ip, #16

		blt	.Lc2u_1rem8lp



.Lc2u_1cpy8lp:	mov	r3, r7, lspull #8

		ldmia	r1!, {r4 - r7}

		subs	ip, ip, #16

		orr	r3, r3, r4, lspush #24

		mov	r4, r4, lspull #8

		orr	r4, r4, r5, lspush #24

		mov	r5, r5, lspull #8

		orr	r5, r5, r6, lspush #24

		mov	r6, r6, lspull #8

		orr	r6, r6, r7, lspush #24

		stmia	r0!, {r3 - r6}			@ Shouldnt fault

		bpl	.Lc2u_1cpy8lp



.Lc2u_1rem8lp:	tst	ip, #8

		movne	r3, r7, lspull #8

		ldmneia	r1!, {r4, r7}

		orrne	r3, r3, r4, lspush #24

		movne	r4, r4, lspull #8

		orrne	r4, r4, r7, lspush #24

		stmneia	r0!, {r3 - r4}			@ Shouldnt fault

		tst	ip, #4

		movne	r3, r7, lspull #8

		ldrne	r7, [r1], #4

		orrne	r3, r3, r7, lspush #24

	TUSER(	strne) r3, [r0], #4			@ Shouldnt fault

		ands	ip, ip, #3

		beq	.Lc2u_1fupi

.Lc2u_1nowords:	mov	r3, r7, get_byte_1

		teq	ip, #0

		beq	.Lc2u_finished

		cmp	ip, #2

USER(	TUSER(	strb)	r3, [r0], #1)			@ May fault

		movge	r3, r7, get_byte_2

USER(	TUSER(	strgeb) r3, [r0], #1)			@ May fault

		movgt	r3, r7, get_byte_3

USER(	TUSER(	strgtb) r3, [r0], #1)			@ May fault

		b	.Lc2u_finished



.Lc2u_2fupi:	subs	r2, r2, #4

		addmi	ip, r2, #4

		bmi	.Lc2u_2nowords

		mov	r3, r7, lspull #16

		ldr	r7, [r1], #4

		orr	r3, r3, r7, lspush #16

USER(	TUSER(	str)	r3, [r0], #4)			@ May fault

		mov	ip, r0, lsl #32 - PAGE_SHIFT

		rsb	ip, ip, #0

		movs	ip, ip, lsr #32 - PAGE_SHIFT

		beq	.Lc2u_2fupi

		cmp	r2, ip

		movlt	ip, r2

		sub	r2, r2, ip

		subs	ip, ip, #16

		blt	.Lc2u_2rem8lp



.Lc2u_2cpy8lp:	mov	r3, r7, lspull #16

		ldmia	r1!, {r4 - r7}

		subs	ip, ip, #16

		orr	r3, r3, r4, lspush #16

		mov	r4, r4, lspull #16

		orr	r4, r4, r5, lspush #16

		mov	r5, r5, lspull #16

		orr	r5, r5, r6, lspush #16

		mov	r6, r6, lspull #16

		orr	r6, r6, r7, lspush #16

		stmia	r0!, {r3 - r6}			@ Shouldnt fault

		bpl	.Lc2u_2cpy8lp



.Lc2u_2rem8lp:	tst	ip, #8

		movne	r3, r7, lspull #16

		ldmneia	r1!, {r4, r7}

		orrne	r3, r3, r4, lspush #16

		movne	r4, r4, lspull #16

		orrne	r4, r4, r7, lspush #16

		stmneia	r0!, {r3 - r4}			@ Shouldnt fault

		tst	ip, #4

		movne	r3, r7, lspull #16

		ldrne	r7, [r1], #4

		orrne	r3, r3, r7, lspush #16

	TUSER(	strne) r3, [r0], #4			@ Shouldnt fault

		ands	ip, ip, #3

		beq	.Lc2u_2fupi

.Lc2u_2nowords:	mov	r3, r7, get_byte_2

		teq	ip, #0

		beq	.Lc2u_finished

		cmp	ip, #2

USER(	TUSER(	strb)	r3, [r0], #1)			@ May fault

		movge	r3, r7, get_byte_3

USER(	TUSER(	strgeb) r3, [r0], #1)			@ May fault

		ldrgtb	r3, [r1], #0

USER(	TUSER(	strgtb) r3, [r0], #1)			@ May fault

		b	.Lc2u_finished



.Lc2u_3fupi:	subs	r2, r2, #4

		addmi	ip, r2, #4

		bmi	.Lc2u_3nowords

		mov	r3, r7, lspull #24

		ldr	r7, [r1], #4

		orr	r3, r3, r7, lspush #8

USER(	TUSER(	str)	r3, [r0], #4)			@ May fault

		mov	ip, r0, lsl #32 - PAGE_SHIFT

		rsb	ip, ip, #0

		movs	ip, ip, lsr #32 - PAGE_SHIFT

		beq	.Lc2u_3fupi

		cmp	r2, ip

		movlt	ip, r2

		sub	r2, r2, ip

		subs	ip, ip, #16

		blt	.Lc2u_3rem8lp



.Lc2u_3cpy8lp:	mov	r3, r7, lspull #24

		ldmia	r1!, {r4 - r7}

		subs	ip, ip, #16

		orr	r3, r3, r4, lspush #8

		mov	r4, r4, lspull #24

		orr	r4, r4, r5, lspush #8

		mov	r5, r5, lspull #24

		orr	r5, r5, r6, lspush #8

		mov	r6, r6, lspull #24

		orr	r6, r6, r7, lspush #8

		stmia	r0!, {r3 - r6}			@ Shouldnt fault

		bpl	.Lc2u_3cpy8lp



.Lc2u_3rem8lp:	tst	ip, #8

		movne	r3, r7, lspull #24

		ldmneia	r1!, {r4, r7}

		orrne	r3, r3, r4, lspush #8

		movne	r4, r4, lspull #24

		orrne	r4, r4, r7, lspush #8

		stmneia	r0!, {r3 - r4}			@ Shouldnt fault

		tst	ip, #4

		movne	r3, r7, lspull #24

		ldrne	r7, [r1], #4

		orrne	r3, r3, r7, lspush #8

	TUSER(	strne) r3, [r0], #4			@ Shouldnt fault

		ands	ip, ip, #3

		beq	.Lc2u_3fupi

.Lc2u_3nowords:	mov	r3, r7, get_byte_3

		teq	ip, #0

		beq	.Lc2u_finished

		cmp	ip, #2

USER(	TUSER(	strb)	r3, [r0], #1)			@ May fault

		ldrgeb	r3, [r1], #1

USER(	TUSER(	strgeb) r3, [r0], #1)			@ May fault

		ldrgtb	r3, [r1], #0

USER(	TUSER(	strgtb) r3, [r0], #1)			@ May fault

		b	.Lc2u_finished

ENDPROC(__copy_to_user)



		.pushsection .fixup,"ax"

		.align	0

9001:		ldmfd	sp!, {r0, r4 - r7, pc}

		.popsection



/* Prototype: unsigned long __copy_from_user(void *to,const void *from,unsigned long n);

 * Purpose  : copy a block from user memory to kernel memory

 * Params   : to   - kernel memory

 *          : from - user memory

 *          : n    - number of bytes to copy

 * Returns  : Number of bytes NOT copied.

 */

.Lcfu_dest_not_aligned:

		rsb	ip, ip, #4

		cmp	ip, #2

USER(	TUSER(	ldrb)	r3, [r1], #1)			@ May fault

		strb	r3, [r0], #1

USER(	TUSER(	ldrgeb) r3, [r1], #1)			@ May fault

		strgeb	r3, [r0], #1

USER(	TUSER(	ldrgtb) r3, [r1], #1)			@ May fault

		strgtb	r3, [r0], #1

		sub	r2, r2, ip

		b	.Lcfu_dest_aligned



ENTRY(__copy_from_user)

		stmfd	sp!, {r0, r2, r4 - r7, lr}

		cmp	r2, #4

		blt	.Lcfu_not_enough

		ands	ip, r0, #3

		bne	.Lcfu_dest_not_aligned

.Lcfu_dest_aligned:

		ands	ip, r1, #3

		bne	.Lcfu_src_not_aligned



/*

 * Seeing as there has to be at least 8 bytes to copy, we can

 * copy one word, and force a user-mode page fault...

 */



.Lcfu_0fupi:	subs	r2, r2, #4

		addmi	ip, r2, #4

		bmi	.Lcfu_0nowords

USER(	TUSER(	ldr)	r3, [r1], #4)

		str	r3, [r0], #4

		mov	ip, r1, lsl #32 - PAGE_SHIFT	@ On each page, use a ld/st??t instruction

		rsb	ip, ip, #0

		movs	ip, ip, lsr #32 - PAGE_SHIFT

		beq	.Lcfu_0fupi

/*

 * ip = max no. of bytes to copy before needing another "strt" insn

 */

		cmp	r2, ip

		movlt	ip, r2

		sub	r2, r2, ip

		subs	ip, ip, #32

		blt	.Lcfu_0rem8lp



.Lcfu_0cpy8lp:	ldmia	r1!, {r3 - r6}			@ Shouldnt fault

		stmia	r0!, {r3 - r6}

		ldmia	r1!, {r3 - r6}			@ Shouldnt fault

		subs	ip, ip, #32

		stmia	r0!, {r3 - r6}

		bpl	.Lcfu_0cpy8lp



.Lcfu_0rem8lp:	cmn	ip, #16

		ldmgeia	r1!, {r3 - r6}			@ Shouldnt fault

		stmgeia	r0!, {r3 - r6}

		tst	ip, #8

		ldmneia	r1!, {r3 - r4}			@ Shouldnt fault

		stmneia	r0!, {r3 - r4}

		tst	ip, #4

	TUSER(	ldrne) r3, [r1], #4			@ Shouldnt fault

		strne	r3, [r0], #4

		ands	ip, ip, #3

		beq	.Lcfu_0fupi

.Lcfu_0nowords:	teq	ip, #0

		beq	.Lcfu_finished

.Lcfu_nowords:	cmp	ip, #2

USER(	TUSER(	ldrb)	r3, [r1], #1)			@ May fault

		strb	r3, [r0], #1

USER(	TUSER(	ldrgeb) r3, [r1], #1)			@ May fault

		strgeb	r3, [r0], #1

USER(	TUSER(	ldrgtb) r3, [r1], #1)			@ May fault

		strgtb	r3, [r0], #1

		b	.Lcfu_finished



.Lcfu_not_enough:

		movs	ip, r2

		bne	.Lcfu_nowords

.Lcfu_finished:	mov	r0, #0

		add	sp, sp, #8

		ldmfd	sp!, {r4 - r7, pc}



.Lcfu_src_not_aligned:

		bic	r1, r1, #3

USER(	TUSER(	ldr)	r7, [r1], #4)			@ May fault

		cmp	ip, #2

		bgt	.Lcfu_3fupi

		beq	.Lcfu_2fupi

.Lcfu_1fupi:	subs	r2, r2, #4

		addmi	ip, r2, #4

		bmi	.Lcfu_1nowords

		mov	r3, r7, lspull #8

USER(	TUSER(	ldr)	r7, [r1], #4)			@ May fault

		orr	r3, r3, r7, lspush #24

		str	r3, [r0], #4

		mov	ip, r1, lsl #32 - PAGE_SHIFT

		rsb	ip, ip, #0

		movs	ip, ip, lsr #32 - PAGE_SHIFT

		beq	.Lcfu_1fupi

		cmp	r2, ip

		movlt	ip, r2

		sub	r2, r2, ip

		subs	ip, ip, #16

		blt	.Lcfu_1rem8lp



.Lcfu_1cpy8lp:	mov	r3, r7, lspull #8

		ldmia	r1!, {r4 - r7}			@ Shouldnt fault

		subs	ip, ip, #16

		orr	r3, r3, r4, lspush #24

		mov	r4, r4, lspull #8

		orr	r4, r4, r5, lspush #24

		mov	r5, r5, lspull #8

		orr	r5, r5, r6, lspush #24

		mov	r6, r6, lspull #8

		orr	r6, r6, r7, lspush #24

		stmia	r0!, {r3 - r6}

		bpl	.Lcfu_1cpy8lp



.Lcfu_1rem8lp:	tst	ip, #8

		movne	r3, r7, lspull #8

		ldmneia	r1!, {r4, r7}			@ Shouldnt fault

		orrne	r3, r3, r4, lspush #24

		movne	r4, r4, lspull #8

		orrne	r4, r4, r7, lspush #24

		stmneia	r0!, {r3 - r4}

		tst	ip, #4

		movne	r3, r7, lspull #8

USER(	TUSER(	ldrne) r7, [r1], #4)			@ May fault

		orrne	r3, r3, r7, lspush #24

		strne	r3, [r0], #4

		ands	ip, ip, #3

		beq	.Lcfu_1fupi

.Lcfu_1nowords:	mov	r3, r7, get_byte_1

		teq	ip, #0

		beq	.Lcfu_finished

		cmp	ip, #2

		strb	r3, [r0], #1

		movge	r3, r7, get_byte_2

		strgeb	r3, [r0], #1

		movgt	r3, r7, get_byte_3

		strgtb	r3, [r0], #1

		b	.Lcfu_finished



.Lcfu_2fupi:	subs	r2, r2, #4

		addmi	ip, r2, #4

		bmi	.Lcfu_2nowords

		mov	r3, r7, lspull #16

USER(	TUSER(	ldr)	r7, [r1], #4)			@ May fault

		orr	r3, r3, r7, lspush #16

		str	r3, [r0], #4

		mov	ip, r1, lsl #32 - PAGE_SHIFT

		rsb	ip, ip, #0

		movs	ip, ip, lsr #32 - PAGE_SHIFT

		beq	.Lcfu_2fupi

		cmp	r2, ip

		movlt	ip, r2

		sub	r2, r2, ip

		subs	ip, ip, #16

		blt	.Lcfu_2rem8lp





.Lcfu_2cpy8lp:	mov	r3, r7, lspull #16

		ldmia	r1!, {r4 - r7}			@ Shouldnt fault

		subs	ip, ip, #16

		orr	r3, r3, r4, lspush #16

		mov	r4, r4, lspull #16

		orr	r4, r4, r5, lspush #16

		mov	r5, r5, lspull #16

		orr	r5, r5, r6, lspush #16

		mov	r6, r6, lspull #16

		orr	r6, r6, r7, lspush #16

		stmia	r0!, {r3 - r6}

		bpl	.Lcfu_2cpy8lp



.Lcfu_2rem8lp:	tst	ip, #8

		movne	r3, r7, lspull #16

		ldmneia	r1!, {r4, r7}			@ Shouldnt fault

		orrne	r3, r3, r4, lspush #16

		movne	r4, r4, lspull #16

		orrne	r4, r4, r7, lspush #16

		stmneia	r0!, {r3 - r4}

		tst	ip, #4

		movne	r3, r7, lspull #16

USER(	TUSER(	ldrne) r7, [r1], #4)			@ May fault

		orrne	r3, r3, r7, lspush #16

		strne	r3, [r0], #4

		ands	ip, ip, #3

		beq	.Lcfu_2fupi

.Lcfu_2nowords:	mov	r3, r7, get_byte_2

		teq	ip, #0

		beq	.Lcfu_finished

		cmp	ip, #2

		strb	r3, [r0], #1

		movge	r3, r7, get_byte_3

		strgeb	r3, [r0], #1

USER(	TUSER(	ldrgtb) r3, [r1], #0)			@ May fault

		strgtb	r3, [r0], #1

		b	.Lcfu_finished



.Lcfu_3fupi:	subs	r2, r2, #4

		addmi	ip, r2, #4

		bmi	.Lcfu_3nowords

		mov	r3, r7, lspull #24

USER(	TUSER(	ldr)	r7, [r1], #4)			@ May fault

		orr	r3, r3, r7, lspush #8

		str	r3, [r0], #4

		mov	ip, r1, lsl #32 - PAGE_SHIFT

		rsb	ip, ip, #0

		movs	ip, ip, lsr #32 - PAGE_SHIFT

		beq	.Lcfu_3fupi

		cmp	r2, ip

		movlt	ip, r2

		sub	r2, r2, ip

		subs	ip, ip, #16

		blt	.Lcfu_3rem8lp



.Lcfu_3cpy8lp:	mov	r3, r7, lspull #24

		ldmia	r1!, {r4 - r7}			@ Shouldnt fault

		orr	r3, r3, r4, lspush #8

		mov	r4, r4, lspull #24

		orr	r4, r4, r5, lspush #8

		mov	r5, r5, lspull #24

		orr	r5, r5, r6, lspush #8

		mov	r6, r6, lspull #24

		orr	r6, r6, r7, lspush #8

		stmia	r0!, {r3 - r6}

		subs	ip, ip, #16

		bpl	.Lcfu_3cpy8lp



.Lcfu_3rem8lp:	tst	ip, #8

		movne	r3, r7, lspull #24

		ldmneia	r1!, {r4, r7}			@ Shouldnt fault

		orrne	r3, r3, r4, lspush #8

		movne	r4, r4, lspull #24

		orrne	r4, r4, r7, lspush #8

		stmneia	r0!, {r3 - r4}

		tst	ip, #4

		movne	r3, r7, lspull #24

USER(	TUSER(	ldrne) r7, [r1], #4)			@ May fault

		orrne	r3, r3, r7, lspush #8

		strne	r3, [r0], #4

		ands	ip, ip, #3

		beq	.Lcfu_3fupi

.Lcfu_3nowords:	mov	r3, r7, get_byte_3

		teq	ip, #0

		beq	.Lcfu_finished

		cmp	ip, #2

		strb	r3, [r0], #1

USER(	TUSER(	ldrgeb) r3, [r1], #1)			@ May fault

		strgeb	r3, [r0], #1

USER(	TUSER(	ldrgtb) r3, [r1], #1)			@ May fault

		strgtb	r3, [r0], #1

		b	.Lcfu_finished

ENDPROC(__copy_from_user)



		.pushsection .fixup,"ax"

		.align	0

		/*

		 * We took an exception.  r0 contains a pointer to

		 * the byte not copied.

		 */

9001:		ldr	r2, [sp], #4			@ void *to

		sub	r2, r0, r2			@ bytes copied

		ldr	r1, [sp], #4			@ unsigned long count

		subs	r4, r1, r2			@ bytes left to copy

		movne	r1, r4

		blne	__memzero

		mov	r0, r4

		ldmfd	sp!, {r4 - r7, pc}

		.popsection

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