alistair23-linux/arch/arm/lib/io-readsl.S

/* SPDX-License-Identifier: GPL-2.0-only */
/*
 *  linux/arch/arm/lib/io-readsl.S
 *
 *  Copyright (C) 1995-2000 Russell King
 */
#include <linux/linkage.h>
#include <asm/assembler.h>

ENTRY(__raw_readsl)
		teq	r2, #0		@ do we have to check for the zero len?
		reteq	lr
		ands	ip, r1, #3
		bne	3f

		subs	r2, r2, #4
		bmi	2f
		stmfd	sp!, {r4, lr}
1:		ldr	r3, [r0, #0]
		ldr	r4, [r0, #0]
		ldr	ip, [r0, #0]
		ldr	lr, [r0, #0]
		subs	r2, r2, #4
		stmia	r1!, {r3, r4, ip, lr}
		bpl	1b
		ldmfd	sp!, {r4, lr}
2:		movs	r2, r2, lsl #31
		ldrcs	r3, [r0, #0]
		ldrcs	ip, [r0, #0]
		stmiacs	r1!, {r3, ip}
		ldrne	r3, [r0, #0]
		strne	r3, [r1, #0]
		ret	lr

3:		ldr	r3, [r0]
		cmp	ip, #2
		mov	ip, r3, get_byte_0
		strb	ip, [r1], #1
		bgt	6f
		mov	ip, r3, get_byte_1
		strb	ip, [r1], #1
		beq	5f
		mov	ip, r3, get_byte_2
		strb	ip, [r1], #1

4:		subs	r2, r2, #1
		mov	ip, r3, lspull #24
		ldrne	r3, [r0]
		orrne	ip, ip, r3, lspush #8
		strne	ip, [r1], #4
		bne	4b
		b	8f

5:		subs	r2, r2, #1
		mov	ip, r3, lspull #16
		ldrne	r3, [r0]
		orrne	ip, ip, r3, lspush #16
		strne	ip, [r1], #4
		bne	5b
		b	7f

6:		subs	r2, r2, #1
		mov	ip, r3, lspull #8
		ldrne	r3, [r0]
		orrne	ip, ip, r3, lspush #24
		strne	ip, [r1], #4
		bne	6b

		mov	r3, ip, get_byte_2
		strb	r3, [r1, #2]
7:		mov	r3, ip, get_byte_1
		strb	r3, [r1, #1]
8:		mov	r3, ip, get_byte_0
		strb	r3, [r1, #0]
		ret	lr
ENDPROC(__raw_readsl)