root/arch/arm/lib/io-readsw-armv3.S
/* SPDX-License-Identifier: GPL-2.0-only */
/*
 *  linux/arch/arm/lib/io-readsw-armv3.S
 *
 *  Copyright (C) 1995-2000 Russell King
 */
#include <linux/linkage.h>
#include <asm/assembler.h>

.Linsw_bad_alignment:
                adr     r0, .Linsw_bad_align_msg
                mov     r2, lr
                b       panic
.Linsw_bad_align_msg:
                .asciz  "insw: bad buffer alignment (0x%p, lr=0x%08lX)\n"
                .align

.Linsw_align:   tst     r1, #1
                bne     .Linsw_bad_alignment

                ldr     r3, [r0]
                strb    r3, [r1], #1
                mov     r3, r3, lsr #8
                strb    r3, [r1], #1

                subs    r2, r2, #1
                reteq   lr

ENTRY(__raw_readsw)
                teq     r2, #0          @ do we have to check for the zero len?
                reteq   lr
                tst     r1, #3
                bne     .Linsw_align

.Linsw_aligned: mov     ip, #0xff
                orr     ip, ip, ip, lsl #8
                stmfd   sp!, {r4, r5, r6, lr}

                subs    r2, r2, #8
                bmi     .Lno_insw_8

.Linsw_8_lp:    ldr     r3, [r0]
                and     r3, r3, ip
                ldr     r4, [r0]
                orr     r3, r3, r4, lsl #16

                ldr     r4, [r0]
                and     r4, r4, ip
                ldr     r5, [r0]
                orr     r4, r4, r5, lsl #16

                ldr     r5, [r0]
                and     r5, r5, ip
                ldr     r6, [r0]
                orr     r5, r5, r6, lsl #16

                ldr     r6, [r0]
                and     r6, r6, ip
                ldr     lr, [r0]
                orr     r6, r6, lr, lsl #16

                stmia   r1!, {r3 - r6}

                subs    r2, r2, #8
                bpl     .Linsw_8_lp

                tst     r2, #7
                ldmfdeq sp!, {r4, r5, r6, pc}

.Lno_insw_8:    tst     r2, #4
                beq     .Lno_insw_4

                ldr     r3, [r0]
                and     r3, r3, ip
                ldr     r4, [r0]
                orr     r3, r3, r4, lsl #16

                ldr     r4, [r0]
                and     r4, r4, ip
                ldr     r5, [r0]
                orr     r4, r4, r5, lsl #16

                stmia   r1!, {r3, r4}

.Lno_insw_4:    tst     r2, #2
                beq     .Lno_insw_2

                ldr     r3, [r0]
                and     r3, r3, ip
                ldr     r4, [r0]
                orr     r3, r3, r4, lsl #16

                str     r3, [r1], #4

.Lno_insw_2:    tst     r2, #1
                ldrne   r3, [r0]
                strbne  r3, [r1], #1
                movne   r3, r3, lsr #8
                strbne  r3, [r1]

                ldmfd   sp!, {r4, r5, r6, pc}