[linux-2.6-block.git] / arch / arm / lib / uaccess.S

/*
 *  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>

		.text

#define PAGE_SHIFT 12

/* Prototype: int __arch_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(		strbt	r3, [r0], #1)			@ May fault
		ldrgeb	r3, [r1], #1
USER(		strgebt	r3, [r0], #1)			@ May fault
		ldrgtb	r3, [r1], #1
USER(		strgtbt	r3, [r0], #1)			@ May fault
		sub	r2, r2, ip
		b	.Lc2u_dest_aligned

ENTRY(__arch_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(		strt	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
		strnet	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(		strbt	r3, [r0], #1)			@ May fault
		ldrgeb	r3, [r1], #1
USER(		strgebt	r3, [r0], #1)			@ May fault
		ldrgtb	r3, [r1], #1
USER(		strgtbt	r3, [r0], #1)			@ May fault
		b	.Lc2u_finished

.Lc2u_not_enough:
		movs	ip, r2
		bne	.Lc2u_nowords
.Lc2u_finished:	mov	r0, #0
		LOADREGS(fd,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, pull #8
		ldr	r7, [r1], #4
		orr	r3, r3, r7, push #24
USER(		strt	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, pull #8
		ldmia	r1!, {r4 - r7}
		subs	ip, ip, #16
		orr	r3, r3, r4, push #24
		mov	r4, r4, pull #8
		orr	r4, r4, r5, push #24
		mov	r5, r5, pull #8
		orr	r5, r5, r6, push #24
		mov	r6, r6, pull #8
		orr	r6, r6, r7, push #24
		stmia	r0!, {r3 - r6}			@ Shouldnt fault
		bpl	.Lc2u_1cpy8lp

.Lc2u_1rem8lp:	tst	ip, #8
		movne	r3, r7, pull #8
		ldmneia	r1!, {r4, r7}
		orrne	r3, r3, r4, push #24
		movne	r4, r4, pull #8
		orrne	r4, r4, r7, push #24
		stmneia	r0!, {r3 - r4}			@ Shouldnt fault
		tst	ip, #4
		movne	r3, r7, pull #8
		ldrne	r7, [r1], #4
		orrne	r3, r3, r7, push #24
		strnet	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(		strbt	r3, [r0], #1)			@ May fault
		movge	r3, r7, get_byte_2
USER(		strgebt	r3, [r0], #1)			@ May fault
		movgt	r3, r7, get_byte_3
USER(		strgtbt	r3, [r0], #1)			@ May fault
		b	.Lc2u_finished

.Lc2u_2fupi:	subs	r2, r2, #4
		addmi	ip, r2, #4
		bmi	.Lc2u_2nowords
		mov	r3, r7, pull #16
		ldr	r7, [r1], #4
		orr	r3, r3, r7, push #16
USER(		strt	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, pull #16
		ldmia	r1!, {r4 - r7}
		subs	ip, ip, #16
		orr	r3, r3, r4, push #16
		mov	r4, r4, pull #16
		orr	r4, r4, r5, push #16
		mov	r5, r5, pull #16
		orr	r5, r5, r6, push #16
		mov	r6, r6, pull #16
		orr	r6, r6, r7, push #16
		stmia	r0!, {r3 - r6}			@ Shouldnt fault
		bpl	.Lc2u_2cpy8lp

.Lc2u_2rem8lp:	tst	ip, #8
		movne	r3, r7, pull #16
		ldmneia	r1!, {r4, r7}
		orrne	r3, r3, r4, push #16
		movne	r4, r4, pull #16
		orrne	r4, r4, r7, push #16
		stmneia	r0!, {r3 - r4}			@ Shouldnt fault
		tst	ip, #4
		movne	r3, r7, pull #16
		ldrne	r7, [r1], #4
		orrne	r3, r3, r7, push #16
		strnet	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(		strbt	r3, [r0], #1)			@ May fault
		movge	r3, r7, get_byte_3
USER(		strgebt	r3, [r0], #1)			@ May fault
		ldrgtb	r3, [r1], #0
USER(		strgtbt	r3, [r0], #1)			@ May fault
		b	.Lc2u_finished

.Lc2u_3fupi:	subs	r2, r2, #4
		addmi	ip, r2, #4
		bmi	.Lc2u_3nowords
		mov	r3, r7, pull #24
		ldr	r7, [r1], #4
		orr	r3, r3, r7, push #8
USER(		strt	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, pull #24
		ldmia	r1!, {r4 - r7}
		subs	ip, ip, #16
		orr	r3, r3, r4, push #8
		mov	r4, r4, pull #24
		orr	r4, r4, r5, push #8
		mov	r5, r5, pull #24
		orr	r5, r5, r6, push #8
		mov	r6, r6, pull #24
		orr	r6, r6, r7, push #8
		stmia	r0!, {r3 - r6}			@ Shouldnt fault
		bpl	.Lc2u_3cpy8lp

.Lc2u_3rem8lp:	tst	ip, #8
		movne	r3, r7, pull #24
		ldmneia	r1!, {r4, r7}
		orrne	r3, r3, r4, push #8
		movne	r4, r4, pull #24
		orrne	r4, r4, r7, push #8
		stmneia	r0!, {r3 - r4}			@ Shouldnt fault
		tst	ip, #4
		movne	r3, r7, pull #24
		ldrne	r7, [r1], #4
		orrne	r3, r3, r7, push #8
		strnet	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(		strbt	r3, [r0], #1)			@ May fault
		ldrgeb	r3, [r1], #1
USER(		strgebt	r3, [r0], #1)			@ May fault
		ldrgtb	r3, [r1], #0
USER(		strgtbt	r3, [r0], #1)			@ May fault
		b	.Lc2u_finished

		.section .fixup,"ax"
		.align	0
9001:		LOADREGS(fd,sp!, {r0, r4 - r7, pc})
		.previous

/* Prototype: unsigned long __arch_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(		ldrbt	r3, [r1], #1)			@ May fault
		strb	r3, [r0], #1
USER(		ldrgebt	r3, [r1], #1)			@ May fault
		strgeb	r3, [r0], #1
USER(		ldrgtbt	r3, [r1], #1)			@ May fault
		strgtb	r3, [r0], #1
		sub	r2, r2, ip
		b	.Lcfu_dest_aligned

ENTRY(__arch_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(		ldrt	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
		ldrnet	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(		ldrbt	r3, [r1], #1)			@ May fault
		strb	r3, [r0], #1
USER(		ldrgebt	r3, [r1], #1)			@ May fault
		strgeb	r3, [r0], #1
USER(		ldrgtbt	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
		LOADREGS(fd,sp!,{r4 - r7, pc})

.Lcfu_src_not_aligned:
		bic	r1, r1, #3
USER(		ldrt	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, pull #8
USER(		ldrt	r7, [r1], #4)			@ May fault
		orr	r3, r3, r7, push #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, pull #8
		ldmia	r1!, {r4 - r7}			@ Shouldnt fault
		subs	ip, ip, #16
		orr	r3, r3, r4, push #24
		mov	r4, r4, pull #8
		orr	r4, r4, r5, push #24
		mov	r5, r5, pull #8
		orr	r5, r5, r6, push #24
		mov	r6, r6, pull #8
		orr	r6, r6, r7, push #24
		stmia	r0!, {r3 - r6}
		bpl	.Lcfu_1cpy8lp

.Lcfu_1rem8lp:	tst	ip, #8
		movne	r3, r7, pull #8
		ldmneia	r1!, {r4, r7}			@ Shouldnt fault
		orrne	r3, r3, r4, push #24
		movne	r4, r4, pull #8
		orrne	r4, r4, r7, push #24
		stmneia	r0!, {r3 - r4}
		tst	ip, #4
		movne	r3, r7, pull #8
USER(		ldrnet	r7, [r1], #4)			@ May fault
		orrne	r3, r3, r7, push #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, pull #16
USER(		ldrt	r7, [r1], #4)			@ May fault
		orr	r3, r3, r7, push #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, pull #16
		ldmia	r1!, {r4 - r7}			@ Shouldnt fault
		subs	ip, ip, #16
		orr	r3, r3, r4, push #16
		mov	r4, r4, pull #16
		orr	r4, r4, r5, push #16
		mov	r5, r5, pull #16
		orr	r5, r5, r6, push #16
		mov	r6, r6, pull #16
		orr	r6, r6, r7, push #16
		stmia	r0!, {r3 - r6}
		bpl	.Lcfu_2cpy8lp

.Lcfu_2rem8lp:	tst	ip, #8
		movne	r3, r7, pull #16
		ldmneia	r1!, {r4, r7}			@ Shouldnt fault
		orrne	r3, r3, r4, push #16
		movne	r4, r4, pull #16
		orrne	r4, r4, r7, push #16
		stmneia	r0!, {r3 - r4}
		tst	ip, #4
		movne	r3, r7, pull #16
USER(		ldrnet	r7, [r1], #4)			@ May fault
		orrne	r3, r3, r7, push #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(		ldrgtbt	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, pull #24
USER(		ldrt	r7, [r1], #4)			@ May fault
		orr	r3, r3, r7, push #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, pull #24
		ldmia	r1!, {r4 - r7}			@ Shouldnt fault
		orr	r3, r3, r4, push #8
		mov	r4, r4, pull #24
		orr	r4, r4, r5, push #8
		mov	r5, r5, pull #24
		orr	r5, r5, r6, push #8
		mov	r6, r6, pull #24
		orr	r6, r6, r7, push #8
		stmia	r0!, {r3 - r6}
		subs	ip, ip, #16
		bpl	.Lcfu_3cpy8lp

.Lcfu_3rem8lp:	tst	ip, #8
		movne	r3, r7, pull #24
		ldmneia	r1!, {r4, r7}			@ Shouldnt fault
		orrne	r3, r3, r4, push #8
		movne	r4, r4, pull #24
		orrne	r4, r4, r7, push #8
		stmneia	r0!, {r3 - r4}
		tst	ip, #4
		movne	r3, r7, pull #24
USER(		ldrnet	r7, [r1], #4)			@ May fault
		orrne	r3, r3, r7, push #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(		ldrgebt	r3, [r1], #1)			@ May fault
		strgeb	r3, [r0], #1
USER(		ldrgtbt	r3, [r1], #1)			@ May fault
		strgtb	r3, [r0], #1
		b	.Lcfu_finished

		.section .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
		LOADREGS(fd,sp!, {r4 - r7, pc})
		.previous
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/arch/arm/lib/uaccess.S
	3	*
	4	* Copyright (C) 1995, 1996,1997,1998 Russell King
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* Routines to block copy data to/from user memory
	11	* These are highly optimised both for the 4k page size
	12	* and for various alignments.
	13	*/
	14	#include <linux/linkage.h>
	15	#include <asm/assembler.h>
	16	#include <asm/errno.h>
	17
	18	.text
	19
	20	#define PAGE_SHIFT 12
	21
	22	/* Prototype: int __arch_copy_to_user(void to, const char from, size_t n)
	23	* Purpose : copy a block to user memory from kernel memory
	24	* Params : to - user memory
	25	* : from - kernel memory
	26	* : n - number of bytes to copy
	27	* Returns : Number of bytes NOT copied.
	28	*/
	29
7ba11a9c	30	.Lc2u_dest_not_aligned:
1da177e4 LT	31	rsb ip, ip, #4
	32	cmp ip, #2
	33	ldrb r3, [r1], #1
	34	USER( strbt r3, [r0], #1) @ May fault
	35	ldrgeb r3, [r1], #1
	36	USER( strgebt r3, [r0], #1) @ May fault
	37	ldrgtb r3, [r1], #1
	38	USER( strgtbt r3, [r0], #1) @ May fault
	39	sub r2, r2, ip
7ba11a9c	40	b .Lc2u_dest_aligned
1da177e4 LT	41
	42	ENTRY(__arch_copy_to_user)
	43	stmfd sp!, {r2, r4 - r7, lr}
	44	cmp r2, #4
7ba11a9c	45	blt .Lc2u_not_enough
1da177e4	46	ands ip, r0, #3
7ba11a9c NP	47	bne .Lc2u_dest_not_aligned
7ba11a9c NP	48	.Lc2u_dest_aligned:
1da177e4 LT	49
1da177e4 LT	50	ands ip, r1, #3
7ba11a9c	51	bne .Lc2u_src_not_aligned
1da177e4 LT	52	/*
	53	* Seeing as there has to be at least 8 bytes to copy, we can
	54	* copy one word, and force a user-mode page fault...
	55	*/
	56
7ba11a9c	57	.Lc2u_0fupi: subs r2, r2, #4
1da177e4	58	addmi ip, r2, #4
7ba11a9c	59	bmi .Lc2u_0nowords
1da177e4 LT	60	ldr r3, [r1], #4
	61	USER( strt r3, [r0], #4) @ May fault
	62	mov ip, r0, lsl #32 - PAGE_SHIFT @ On each page, use a ld/st??t instruction
	63	rsb ip, ip, #0
	64	movs ip, ip, lsr #32 - PAGE_SHIFT
7ba11a9c	65	beq .Lc2u_0fupi
1da177e4 LT	66	/*
	67	* ip = max no. of bytes to copy before needing another "strt" insn
	68	*/
	69	cmp r2, ip
	70	movlt ip, r2
	71	sub r2, r2, ip
	72	subs ip, ip, #32
7ba11a9c	73	blt .Lc2u_0rem8lp
73f0f7c7	74
7ba11a9c	75	.Lc2u_0cpy8lp: ldmia r1!, {r3 - r6}
1da177e4 LT	76	stmia r0!, {r3 - r6} @ Shouldnt fault
	77	ldmia r1!, {r3 - r6}
	78	subs ip, ip, #32
	79	stmia r0!, {r3 - r6} @ Shouldnt fault
7ba11a9c	80	bpl .Lc2u_0cpy8lp
1da177e4	81
7ba11a9c	82	.Lc2u_0rem8lp: cmn ip, #16
1da177e4 LT	83	ldmgeia r1!, {r3 - r6}
	84	stmgeia r0!, {r3 - r6} @ Shouldnt fault
	85	tst ip, #8
	86	ldmneia r1!, {r3 - r4}
	87	stmneia r0!, {r3 - r4} @ Shouldnt fault
	88	tst ip, #4
	89	ldrne r3, [r1], #4
	90	strnet r3, [r0], #4 @ Shouldnt fault
	91	ands ip, ip, #3
7ba11a9c NP	92	beq .Lc2u_0fupi
	93	.Lc2u_0nowords: teq ip, #0
	94	beq .Lc2u_finished
	95	.Lc2u_nowords: cmp ip, #2
1da177e4 LT	96	ldrb r3, [r1], #1
	97	USER( strbt r3, [r0], #1) @ May fault
	98	ldrgeb r3, [r1], #1
	99	USER( strgebt r3, [r0], #1) @ May fault
	100	ldrgtb r3, [r1], #1
	101	USER( strgtbt r3, [r0], #1) @ May fault
7ba11a9c	102	b .Lc2u_finished
1da177e4	103
7ba11a9c	104	.Lc2u_not_enough:
1da177e4	105	movs ip, r2
7ba11a9c NP	106	bne .Lc2u_nowords
7ba11a9c NP	107	.Lc2u_finished: mov r0, #0
1da177e4 LT	108	LOADREGS(fd,sp!,{r2, r4 - r7, pc})
1da177e4 LT	109
7ba11a9c	110	.Lc2u_src_not_aligned:
1da177e4 LT	111	bic r1, r1, #3
	112	ldr r7, [r1], #4
	113	cmp ip, #2
7ba11a9c NP	114	bgt .Lc2u_3fupi
	115	beq .Lc2u_2fupi
	116	.Lc2u_1fupi: subs r2, r2, #4
1da177e4	117	addmi ip, r2, #4
7ba11a9c	118	bmi .Lc2u_1nowords
1da177e4 LT	119	mov r3, r7, pull #8
	120	ldr r7, [r1], #4
	121	orr r3, r3, r7, push #24
	122	USER( strt r3, [r0], #4) @ May fault
	123	mov ip, r0, lsl #32 - PAGE_SHIFT
	124	rsb ip, ip, #0
	125	movs ip, ip, lsr #32 - PAGE_SHIFT
7ba11a9c	126	beq .Lc2u_1fupi
1da177e4 LT	127	cmp r2, ip
	128	movlt ip, r2
	129	sub r2, r2, ip
	130	subs ip, ip, #16
7ba11a9c	131	blt .Lc2u_1rem8lp
73f0f7c7	132
7ba11a9c	133	.Lc2u_1cpy8lp: mov r3, r7, pull #8
1da177e4 LT	134	ldmia r1!, {r4 - r7}
	135	subs ip, ip, #16
	136	orr r3, r3, r4, push #24
	137	mov r4, r4, pull #8
	138	orr r4, r4, r5, push #24
	139	mov r5, r5, pull #8
	140	orr r5, r5, r6, push #24
	141	mov r6, r6, pull #8
	142	orr r6, r6, r7, push #24
	143	stmia r0!, {r3 - r6} @ Shouldnt fault
7ba11a9c	144	bpl .Lc2u_1cpy8lp
1da177e4	145
7ba11a9c	146	.Lc2u_1rem8lp: tst ip, #8
1da177e4 LT	147	movne r3, r7, pull #8
	148	ldmneia r1!, {r4, r7}
	149	orrne r3, r3, r4, push #24
	150	movne r4, r4, pull #8
	151	orrne r4, r4, r7, push #24
	152	stmneia r0!, {r3 - r4} @ Shouldnt fault
	153	tst ip, #4
	154	movne r3, r7, pull #8
	155	ldrne r7, [r1], #4
	156	orrne r3, r3, r7, push #24
	157	strnet r3, [r0], #4 @ Shouldnt fault
	158	ands ip, ip, #3
7ba11a9c NP	159	beq .Lc2u_1fupi
7ba11a9c NP	160	.Lc2u_1nowords: mov r3, r7, get_byte_1
1da177e4	161	teq ip, #0
7ba11a9c	162	beq .Lc2u_finished
1da177e4 LT	163	cmp ip, #2
	164	USER( strbt r3, [r0], #1) @ May fault
	165	movge r3, r7, get_byte_2
	166	USER( strgebt r3, [r0], #1) @ May fault
	167	movgt r3, r7, get_byte_3
	168	USER( strgtbt r3, [r0], #1) @ May fault
7ba11a9c	169	b .Lc2u_finished
1da177e4	170
7ba11a9c	171	.Lc2u_2fupi: subs r2, r2, #4
1da177e4	172	addmi ip, r2, #4
7ba11a9c	173	bmi .Lc2u_2nowords
1da177e4 LT	174	mov r3, r7, pull #16
	175	ldr r7, [r1], #4
	176	orr r3, r3, r7, push #16
	177	USER( strt r3, [r0], #4) @ May fault
	178	mov ip, r0, lsl #32 - PAGE_SHIFT
	179	rsb ip, ip, #0
	180	movs ip, ip, lsr #32 - PAGE_SHIFT
7ba11a9c	181	beq .Lc2u_2fupi
1da177e4 LT	182	cmp r2, ip
	183	movlt ip, r2
	184	sub r2, r2, ip
	185	subs ip, ip, #16
7ba11a9c	186	blt .Lc2u_2rem8lp
73f0f7c7	187
7ba11a9c	188	.Lc2u_2cpy8lp: mov r3, r7, pull #16
1da177e4 LT	189	ldmia r1!, {r4 - r7}
	190	subs ip, ip, #16
	191	orr r3, r3, r4, push #16
	192	mov r4, r4, pull #16
	193	orr r4, r4, r5, push #16
	194	mov r5, r5, pull #16
	195	orr r5, r5, r6, push #16
	196	mov r6, r6, pull #16
	197	orr r6, r6, r7, push #16
	198	stmia r0!, {r3 - r6} @ Shouldnt fault
7ba11a9c	199	bpl .Lc2u_2cpy8lp
1da177e4	200
7ba11a9c	201	.Lc2u_2rem8lp: tst ip, #8
1da177e4 LT	202	movne r3, r7, pull #16
	203	ldmneia r1!, {r4, r7}
	204	orrne r3, r3, r4, push #16
	205	movne r4, r4, pull #16
	206	orrne r4, r4, r7, push #16
	207	stmneia r0!, {r3 - r4} @ Shouldnt fault
	208	tst ip, #4
	209	movne r3, r7, pull #16
	210	ldrne r7, [r1], #4
	211	orrne r3, r3, r7, push #16
	212	strnet r3, [r0], #4 @ Shouldnt fault
	213	ands ip, ip, #3
7ba11a9c NP	214	beq .Lc2u_2fupi
7ba11a9c NP	215	.Lc2u_2nowords: mov r3, r7, get_byte_2
1da177e4	216	teq ip, #0
7ba11a9c	217	beq .Lc2u_finished
1da177e4 LT	218	cmp ip, #2
	219	USER( strbt r3, [r0], #1) @ May fault
	220	movge r3, r7, get_byte_3
	221	USER( strgebt r3, [r0], #1) @ May fault
	222	ldrgtb r3, [r1], #0
	223	USER( strgtbt r3, [r0], #1) @ May fault
7ba11a9c	224	b .Lc2u_finished
1da177e4	225
7ba11a9c	226	.Lc2u_3fupi: subs r2, r2, #4
1da177e4	227	addmi ip, r2, #4
7ba11a9c	228	bmi .Lc2u_3nowords
1da177e4 LT	229	mov r3, r7, pull #24
	230	ldr r7, [r1], #4
	231	orr r3, r3, r7, push #8
	232	USER( strt r3, [r0], #4) @ May fault
	233	mov ip, r0, lsl #32 - PAGE_SHIFT
	234	rsb ip, ip, #0
	235	movs ip, ip, lsr #32 - PAGE_SHIFT
7ba11a9c	236	beq .Lc2u_3fupi
1da177e4 LT	237	cmp r2, ip
	238	movlt ip, r2
	239	sub r2, r2, ip
	240	subs ip, ip, #16
7ba11a9c	241	blt .Lc2u_3rem8lp
73f0f7c7	242
7ba11a9c	243	.Lc2u_3cpy8lp: mov r3, r7, pull #24
1da177e4 LT	244	ldmia r1!, {r4 - r7}
	245	subs ip, ip, #16
	246	orr r3, r3, r4, push #8
	247	mov r4, r4, pull #24
	248	orr r4, r4, r5, push #8
	249	mov r5, r5, pull #24
	250	orr r5, r5, r6, push #8
	251	mov r6, r6, pull #24
	252	orr r6, r6, r7, push #8
	253	stmia r0!, {r3 - r6} @ Shouldnt fault
7ba11a9c	254	bpl .Lc2u_3cpy8lp
1da177e4	255
7ba11a9c	256	.Lc2u_3rem8lp: tst ip, #8
1da177e4 LT	257	movne r3, r7, pull #24
	258	ldmneia r1!, {r4, r7}
	259	orrne r3, r3, r4, push #8
	260	movne r4, r4, pull #24
	261	orrne r4, r4, r7, push #8
	262	stmneia r0!, {r3 - r4} @ Shouldnt fault
	263	tst ip, #4
	264	movne r3, r7, pull #24
	265	ldrne r7, [r1], #4
	266	orrne r3, r3, r7, push #8
	267	strnet r3, [r0], #4 @ Shouldnt fault
	268	ands ip, ip, #3
7ba11a9c NP	269	beq .Lc2u_3fupi
7ba11a9c NP	270	.Lc2u_3nowords: mov r3, r7, get_byte_3
1da177e4	271	teq ip, #0
7ba11a9c	272	beq .Lc2u_finished
1da177e4 LT	273	cmp ip, #2
	274	USER( strbt r3, [r0], #1) @ May fault
	275	ldrgeb r3, [r1], #1
	276	USER( strgebt r3, [r0], #1) @ May fault
	277	ldrgtb r3, [r1], #0
	278	USER( strgtbt r3, [r0], #1) @ May fault
7ba11a9c	279	b .Lc2u_finished
1da177e4 LT	280
	281	.section .fixup,"ax"
	282	.align 0
	283	9001: LOADREGS(fd,sp!, {r0, r4 - r7, pc})
	284	.previous
	285
	286	/* Prototype: unsigned long __arch_copy_from_user(void to,const void from,unsigned long n);
	287	* Purpose : copy a block from user memory to kernel memory
	288	* Params : to - kernel memory
	289	* : from - user memory
	290	* : n - number of bytes to copy
	291	* Returns : Number of bytes NOT copied.
	292	*/
7ba11a9c	293	.Lcfu_dest_not_aligned:
1da177e4 LT	294	rsb ip, ip, #4
	295	cmp ip, #2
	296	USER( ldrbt r3, [r1], #1) @ May fault
	297	strb r3, [r0], #1
	298	USER( ldrgebt r3, [r1], #1) @ May fault
	299	strgeb r3, [r0], #1
	300	USER( ldrgtbt r3, [r1], #1) @ May fault
	301	strgtb r3, [r0], #1
	302	sub r2, r2, ip
7ba11a9c	303	b .Lcfu_dest_aligned
1da177e4 LT	304
	305	ENTRY(__arch_copy_from_user)
	306	stmfd sp!, {r0, r2, r4 - r7, lr}
	307	cmp r2, #4
7ba11a9c	308	blt .Lcfu_not_enough
1da177e4	309	ands ip, r0, #3
7ba11a9c NP	310	bne .Lcfu_dest_not_aligned
7ba11a9c NP	311	.Lcfu_dest_aligned:
1da177e4	312	ands ip, r1, #3
7ba11a9c NP	313	bne .Lcfu_src_not_aligned
7ba11a9c NP	314
1da177e4 LT	315	/*
	316	* Seeing as there has to be at least 8 bytes to copy, we can
	317	* copy one word, and force a user-mode page fault...
	318	*/
	319
7ba11a9c	320	.Lcfu_0fupi: subs r2, r2, #4
1da177e4	321	addmi ip, r2, #4
7ba11a9c	322	bmi .Lcfu_0nowords
1da177e4 LT	323	USER( ldrt r3, [r1], #4)
	324	str r3, [r0], #4
	325	mov ip, r1, lsl #32 - PAGE_SHIFT @ On each page, use a ld/st??t instruction
	326	rsb ip, ip, #0
	327	movs ip, ip, lsr #32 - PAGE_SHIFT
7ba11a9c	328	beq .Lcfu_0fupi
1da177e4 LT	329	/*
	330	* ip = max no. of bytes to copy before needing another "strt" insn
	331	*/
	332	cmp r2, ip
	333	movlt ip, r2
	334	sub r2, r2, ip
	335	subs ip, ip, #32
7ba11a9c	336	blt .Lcfu_0rem8lp
73f0f7c7	337
7ba11a9c	338	.Lcfu_0cpy8lp: ldmia r1!, {r3 - r6} @ Shouldnt fault
1da177e4 LT	339	stmia r0!, {r3 - r6}
	340	ldmia r1!, {r3 - r6} @ Shouldnt fault
	341	subs ip, ip, #32
	342	stmia r0!, {r3 - r6}
7ba11a9c	343	bpl .Lcfu_0cpy8lp
1da177e4	344
7ba11a9c	345	.Lcfu_0rem8lp: cmn ip, #16
1da177e4 LT	346	ldmgeia r1!, {r3 - r6} @ Shouldnt fault
	347	stmgeia r0!, {r3 - r6}
	348	tst ip, #8
	349	ldmneia r1!, {r3 - r4} @ Shouldnt fault
	350	stmneia r0!, {r3 - r4}
	351	tst ip, #4
	352	ldrnet r3, [r1], #4 @ Shouldnt fault
	353	strne r3, [r0], #4
	354	ands ip, ip, #3
7ba11a9c NP	355	beq .Lcfu_0fupi
	356	.Lcfu_0nowords: teq ip, #0
	357	beq .Lcfu_finished
	358	.Lcfu_nowords: cmp ip, #2
1da177e4 LT	359	USER( ldrbt r3, [r1], #1) @ May fault
	360	strb r3, [r0], #1
	361	USER( ldrgebt r3, [r1], #1) @ May fault
	362	strgeb r3, [r0], #1
	363	USER( ldrgtbt r3, [r1], #1) @ May fault
	364	strgtb r3, [r0], #1
7ba11a9c	365	b .Lcfu_finished
1da177e4	366
7ba11a9c	367	.Lcfu_not_enough:
1da177e4	368	movs ip, r2
7ba11a9c NP	369	bne .Lcfu_nowords
7ba11a9c NP	370	.Lcfu_finished: mov r0, #0
1da177e4 LT	371	add sp, sp, #8
	372	LOADREGS(fd,sp!,{r4 - r7, pc})
	373
7ba11a9c	374	.Lcfu_src_not_aligned:
1da177e4 LT	375	bic r1, r1, #3
	376	USER( ldrt r7, [r1], #4) @ May fault
	377	cmp ip, #2
7ba11a9c NP	378	bgt .Lcfu_3fupi
	379	beq .Lcfu_2fupi
	380	.Lcfu_1fupi: subs r2, r2, #4
1da177e4	381	addmi ip, r2, #4
7ba11a9c	382	bmi .Lcfu_1nowords
1da177e4 LT	383	mov r3, r7, pull #8
	384	USER( ldrt r7, [r1], #4) @ May fault
	385	orr r3, r3, r7, push #24
	386	str r3, [r0], #4
	387	mov ip, r1, lsl #32 - PAGE_SHIFT
	388	rsb ip, ip, #0
	389	movs ip, ip, lsr #32 - PAGE_SHIFT
7ba11a9c	390	beq .Lcfu_1fupi
1da177e4 LT	391	cmp r2, ip
	392	movlt ip, r2
	393	sub r2, r2, ip
	394	subs ip, ip, #16
7ba11a9c	395	blt .Lcfu_1rem8lp
73f0f7c7	396
7ba11a9c	397	.Lcfu_1cpy8lp: mov r3, r7, pull #8
1da177e4 LT	398	ldmia r1!, {r4 - r7} @ Shouldnt fault
	399	subs ip, ip, #16
	400	orr r3, r3, r4, push #24
	401	mov r4, r4, pull #8
	402	orr r4, r4, r5, push #24
	403	mov r5, r5, pull #8
	404	orr r5, r5, r6, push #24
	405	mov r6, r6, pull #8
	406	orr r6, r6, r7, push #24
	407	stmia r0!, {r3 - r6}
7ba11a9c	408	bpl .Lcfu_1cpy8lp
1da177e4	409
7ba11a9c	410	.Lcfu_1rem8lp: tst ip, #8
1da177e4 LT	411	movne r3, r7, pull #8
	412	ldmneia r1!, {r4, r7} @ Shouldnt fault
	413	orrne r3, r3, r4, push #24
	414	movne r4, r4, pull #8
	415	orrne r4, r4, r7, push #24
	416	stmneia r0!, {r3 - r4}
	417	tst ip, #4
	418	movne r3, r7, pull #8
	419	USER( ldrnet r7, [r1], #4) @ May fault
	420	orrne r3, r3, r7, push #24
	421	strne r3, [r0], #4
	422	ands ip, ip, #3
7ba11a9c NP	423	beq .Lcfu_1fupi
7ba11a9c NP	424	.Lcfu_1nowords: mov r3, r7, get_byte_1
1da177e4	425	teq ip, #0
7ba11a9c	426	beq .Lcfu_finished
1da177e4 LT	427	cmp ip, #2
	428	strb r3, [r0], #1
	429	movge r3, r7, get_byte_2
	430	strgeb r3, [r0], #1
	431	movgt r3, r7, get_byte_3
	432	strgtb r3, [r0], #1
7ba11a9c	433	b .Lcfu_finished
1da177e4	434
7ba11a9c	435	.Lcfu_2fupi: subs r2, r2, #4
1da177e4	436	addmi ip, r2, #4
7ba11a9c	437	bmi .Lcfu_2nowords
1da177e4 LT	438	mov r3, r7, pull #16
	439	USER( ldrt r7, [r1], #4) @ May fault
	440	orr r3, r3, r7, push #16
	441	str r3, [r0], #4
	442	mov ip, r1, lsl #32 - PAGE_SHIFT
	443	rsb ip, ip, #0
	444	movs ip, ip, lsr #32 - PAGE_SHIFT
7ba11a9c	445	beq .Lcfu_2fupi
1da177e4 LT	446	cmp r2, ip
	447	movlt ip, r2
	448	sub r2, r2, ip
	449	subs ip, ip, #16
7ba11a9c NP	450	blt .Lcfu_2rem8lp
7ba11a9c NP	451
73f0f7c7	452
7ba11a9c	453	.Lcfu_2cpy8lp: mov r3, r7, pull #16
1da177e4 LT	454	ldmia r1!, {r4 - r7} @ Shouldnt fault
	455	subs ip, ip, #16
	456	orr r3, r3, r4, push #16
	457	mov r4, r4, pull #16
	458	orr r4, r4, r5, push #16
	459	mov r5, r5, pull #16
	460	orr r5, r5, r6, push #16
	461	mov r6, r6, pull #16
	462	orr r6, r6, r7, push #16
	463	stmia r0!, {r3 - r6}
7ba11a9c	464	bpl .Lcfu_2cpy8lp
1da177e4	465
7ba11a9c	466	.Lcfu_2rem8lp: tst ip, #8
1da177e4 LT	467	movne r3, r7, pull #16
	468	ldmneia r1!, {r4, r7} @ Shouldnt fault
	469	orrne r3, r3, r4, push #16
	470	movne r4, r4, pull #16
	471	orrne r4, r4, r7, push #16
	472	stmneia r0!, {r3 - r4}
	473	tst ip, #4
	474	movne r3, r7, pull #16
	475	USER( ldrnet r7, [r1], #4) @ May fault
	476	orrne r3, r3, r7, push #16
	477	strne r3, [r0], #4
	478	ands ip, ip, #3
7ba11a9c NP	479	beq .Lcfu_2fupi
7ba11a9c NP	480	.Lcfu_2nowords: mov r3, r7, get_byte_2
1da177e4	481	teq ip, #0
7ba11a9c	482	beq .Lcfu_finished
1da177e4 LT	483	cmp ip, #2
	484	strb r3, [r0], #1
	485	movge r3, r7, get_byte_3
	486	strgeb r3, [r0], #1
	487	USER( ldrgtbt r3, [r1], #0) @ May fault
	488	strgtb r3, [r0], #1
7ba11a9c	489	b .Lcfu_finished
1da177e4	490
7ba11a9c	491	.Lcfu_3fupi: subs r2, r2, #4
1da177e4	492	addmi ip, r2, #4
7ba11a9c	493	bmi .Lcfu_3nowords
1da177e4 LT	494	mov r3, r7, pull #24
	495	USER( ldrt r7, [r1], #4) @ May fault
	496	orr r3, r3, r7, push #8
	497	str r3, [r0], #4
	498	mov ip, r1, lsl #32 - PAGE_SHIFT
	499	rsb ip, ip, #0
	500	movs ip, ip, lsr #32 - PAGE_SHIFT
7ba11a9c	501	beq .Lcfu_3fupi
1da177e4 LT	502	cmp r2, ip
	503	movlt ip, r2
	504	sub r2, r2, ip
	505	subs ip, ip, #16
7ba11a9c	506	blt .Lcfu_3rem8lp
73f0f7c7	507
7ba11a9c	508	.Lcfu_3cpy8lp: mov r3, r7, pull #24
1da177e4 LT	509	ldmia r1!, {r4 - r7} @ Shouldnt fault
	510	orr r3, r3, r4, push #8
	511	mov r4, r4, pull #24
	512	orr r4, r4, r5, push #8
	513	mov r5, r5, pull #24
	514	orr r5, r5, r6, push #8
	515	mov r6, r6, pull #24
	516	orr r6, r6, r7, push #8
	517	stmia r0!, {r3 - r6}
	518	subs ip, ip, #16
7ba11a9c	519	bpl .Lcfu_3cpy8lp
1da177e4	520
7ba11a9c	521	.Lcfu_3rem8lp: tst ip, #8
1da177e4 LT	522	movne r3, r7, pull #24
	523	ldmneia r1!, {r4, r7} @ Shouldnt fault
	524	orrne r3, r3, r4, push #8
	525	movne r4, r4, pull #24
	526	orrne r4, r4, r7, push #8
	527	stmneia r0!, {r3 - r4}
	528	tst ip, #4
	529	movne r3, r7, pull #24
	530	USER( ldrnet r7, [r1], #4) @ May fault
	531	orrne r3, r3, r7, push #8
	532	strne r3, [r0], #4
	533	ands ip, ip, #3
7ba11a9c NP	534	beq .Lcfu_3fupi
7ba11a9c NP	535	.Lcfu_3nowords: mov r3, r7, get_byte_3
1da177e4	536	teq ip, #0
7ba11a9c	537	beq .Lcfu_finished
1da177e4 LT	538	cmp ip, #2
	539	strb r3, [r0], #1
	540	USER( ldrgebt r3, [r1], #1) @ May fault
	541	strgeb r3, [r0], #1
	542	USER( ldrgtbt r3, [r1], #1) @ May fault
	543	strgtb r3, [r0], #1
7ba11a9c	544	b .Lcfu_finished
1da177e4 LT	545
	546	.section .fixup,"ax"
	547	.align 0
	548	/*
	549	* We took an exception. r0 contains a pointer to
	550	* the byte not copied.
	551	*/
	552	9001: ldr r2, [sp], #4 @ void *to
	553	sub r2, r0, r2 @ bytes copied
	554	ldr r1, [sp], #4 @ unsigned long count
	555	subs r4, r1, r2 @ bytes left to copy
	556	movne r1, r4
	557	blne __memzero
	558	mov r0, r4
	559	LOADREGS(fd,sp!, {r4 - r7, pc})
	560	.previous
	561