arm/lib/io-readsw-armv4.S

0001 /* SPDX-License-Identifier: GPL-2.0-only */
0002 /*
0003  *  linux/arch/arm/lib/io-readsw-armv4.S
0004  *
0005  *  Copyright (C) 1995-2000 Russell King
0006  */
0007 #include <linux/linkage.h>
0008 #include <asm/assembler.h>
0009
0010         .macro  pack, rd, hw1, hw2
0011 #ifndef __ARMEB__
0012         orr \rd, \hw1, \hw2, lsl #16
0013 #else
0014         orr \rd, \hw2, \hw1, lsl #16
0015 #endif
0016         .endm
0017
0018 .Linsw_align:   movs    ip, r1, lsl #31
0019         bne .Linsw_noalign
0020         ldrh    ip, [r0]
0021         sub r2, r2, #1
0022         strh    ip, [r1], #2
0023
0024 ENTRY(__raw_readsw)
0025         teq r2, #0
0026         reteq   lr
0027         tst r1, #3
0028         bne .Linsw_align
0029
0030         stmfd   sp!, {r4, r5, lr}
0031
0032         subs    r2, r2, #8
0033         bmi .Lno_insw_8
0034
0035 .Linsw_8_lp:    ldrh    r3, [r0]
0036         ldrh    r4, [r0]
0037         pack    r3, r3, r4
0038
0039         ldrh    r4, [r0]
0040         ldrh    r5, [r0]
0041         pack    r4, r4, r5
0042
0043         ldrh    r5, [r0]
0044         ldrh    ip, [r0]
0045         pack    r5, r5, ip
0046
0047         ldrh    ip, [r0]
0048         ldrh    lr, [r0]
0049         pack    ip, ip, lr
0050
0051         subs    r2, r2, #8
0052         stmia   r1!, {r3 - r5, ip}
0053         bpl .Linsw_8_lp
0054
0055 .Lno_insw_8:    tst r2, #4
0056         beq .Lno_insw_4
0057
0058         ldrh    r3, [r0]
0059         ldrh    r4, [r0]
0060         pack    r3, r3, r4
0061
0062         ldrh    r4, [r0]
0063         ldrh    ip, [r0]
0064         pack    r4, r4, ip
0065
0066         stmia   r1!, {r3, r4}
0067
0068 .Lno_insw_4:    movs    r2, r2, lsl #31
0069         bcc .Lno_insw_2
0070
0071         ldrh    r3, [r0]
0072         ldrh    ip, [r0]
0073         pack    r3, r3, ip
0074         str r3, [r1], #4
0075
0076 .Lno_insw_2:    ldrhne  r3, [r0]
0077         strhne  r3, [r1]
0078
0079         ldmfd   sp!, {r4, r5, pc}
0080
0081 #ifdef __ARMEB__
0082 #define _BE_ONLY_(code...)  code
0083 #define _LE_ONLY_(code...)
0084 #define push_hbyte0     lsr #8
0085 #define pull_hbyte1     lsl #24
0086 #else
0087 #define _BE_ONLY_(code...)
0088 #define _LE_ONLY_(code...) code
0089 #define push_hbyte0     lsl #24
0090 #define pull_hbyte1     lsr #8
0091 #endif
0092
0093 .Linsw_noalign: stmfd   sp!, {r4, lr}
0094         ldrbcc  ip, [r1, #-1]!
0095         bcc 1f
0096
0097         ldrh    ip, [r0]
0098         sub r2, r2, #1
0099    _BE_ONLY_(   mov ip, ip, ror #8      )
0100         strb    ip, [r1], #1
0101    _LE_ONLY_(   mov ip, ip, lsr #8      )
0102    _BE_ONLY_(   mov ip, ip, lsr #24     )
0103
0104 1:      subs    r2, r2, #2
0105         bmi 3f
0106    _BE_ONLY_(   mov ip, ip, lsl #24     )
0107
0108 2:      ldrh    r3, [r0]
0109         ldrh    r4, [r0]
0110         subs    r2, r2, #2
0111         orr ip, ip, r3, lsl #8
0112         orr ip, ip, r4, push_hbyte0
0113         str ip, [r1], #4
0114         mov ip, r4, pull_hbyte1
0115         bpl 2b
0116
0117    _BE_ONLY_(   mov ip, ip, lsr #24     )
0118
0119 3:      tst r2, #1
0120         strb    ip, [r1], #1
0121         ldrhne  ip, [r0]
0122    _BE_ONLY_(   movne   ip, ip, ror #8      )
0123         strbne  ip, [r1], #1
0124    _LE_ONLY_(   movne   ip, ip, lsr #8      )
0125    _BE_ONLY_(   movne   ip, ip, lsr #24     )
0126         strbne  ip, [r1]
0127         ldmfd   sp!, {r4, pc}
0128 ENDPROC(__raw_readsw)