/* *  linux/arch/arm/lib/memzero.S * *  Copyright (C) 1995-2000 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. */#include <linux/linkage.h>#include <asm/assembler.h> 	.text	.align	5	.word	0/* * Align the pointer in r0.  r3 contains the number of bytes that we are * mis-aligned by, and r1 is the number of bytes.  If r1 < 4, then we * don't bother; we use byte stores instead. */1:	subs	r1, r1, #4		@ 1 do we have enough	blt	5f			@ 1 bytes to align with?	cmp	r3, #2			@ 1	strltb	r2, [r0], #1		@ 1	strleb	r2, [r0], #1		@ 1	strb	r2, [r0], #1		@ 1	add	r1, r1, r3		@ 1 (r1 = r1 - (4 - r3))/* * The pointer is now aligned and the length is adjusted.  Try doing the * memzero again. */ ENTRY(__memzero)	mov	r2, #0			@ 1	ands	r3, r0, #3		@ 1 unaligned?	bne	1b			@ 1/* * r3 = 0, and we know that the pointer in r0 is aligned to a word boundary. */	cmp	r1, #16			@ 1 we can skip this chunk if we	blt	4f			@ 1 have < 16 bytes #if ! CALGN(1)+0 /* * We need an extra register for this loop - save the return address and * use the LR */	str	lr, [sp, #-4]!		@ 1	mov	ip, r2			@ 1	mov	lr, r2			@ 1 3:	subs	r1, r1, #64		@ 1 write 32 bytes out per loop	stmgeia	r0!, {r2, r3, ip, lr}	@ 4	stmgeia	r0!, {r2, r3, ip, lr}	@ 4	stmgeia	r0!, {r2, r3, ip, lr}	@ 4	stmgeia	r0!, {r2, r3, ip, lr}	@ 4	bgt	3b			@ 1	ldmeqfd	sp!, {pc}		@ 1/2 quick exit/* * No need to correct the count; we're only testing bits from now on */	tst	r1, #32			@ 1	stmneia	r0!, {r2, r3, ip, lr}	@ 4	stmneia	r0!, {r2, r3, ip, lr}	@ 4	tst	r1, #16			@ 1 16 bytes or more?	stmneia	r0!, {r2, r3, ip, lr}	@ 4	ldr	lr, [sp], #4		@ 1 #else /* * This version aligns the destination pointer in order to write * whole cache lines at once. */ 	stmfd	sp!, {r4-r7, lr}	mov	r4, r2	mov	r5, r2	mov	r6, r2	mov	r7, r2	mov	ip, r2	mov	lr, r2 	cmp	r1, #96	andgts	ip, r0, #31	ble	3f 	rsb	ip, ip, #32	sub	r1, r1, ip	movs	ip, ip, lsl #(32 - 4)	stmcsia	r0!, {r4, r5, r6, r7}	stmmiia	r0!, {r4, r5}	movs	ip, ip, lsl #2	strcs	r2, [r0], #4 3:	subs	r1, r1, #64	stmgeia	r0!, {r2-r7, ip, lr}	stmgeia	r0!, {r2-r7, ip, lr}	bgt	3b	ldmeqfd	sp!, {r4-r7, pc} 	tst	r1, #32	stmneia	r0!, {r2-r7, ip, lr}	tst	r1, #16	stmneia	r0!, {r4-r7}	ldmfd	sp!, {r4-r7, lr} #endif 4:	tst	r1, #8			@ 1 8 bytes or more?	stmneia	r0!, {r2, r3}		@ 2	tst	r1, #4			@ 1 4 bytes or more?	strne	r2, [r0], #4		@ 1/* * When we get here, we've got less than 4 bytes to zero.  We * may have an unaligned pointer as well. */5:	tst	r1, #2			@ 1 2 bytes or more?	strneb	r2, [r0], #1		@ 1	strneb	r2, [r0], #1		@ 1	tst	r1, #1			@ 1 a byte left over	strneb	r2, [r0], #1		@ 1	mov	pc, lr			@ 1ENDPROC(__memzero)