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   1 /*
   2  *  linux/arch/arm/lib/io-readsw-armv4.S
   3  *
   4  *  Copyright (C) 1995-2000 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 #include <linux/linkage.h>
  11 #include <asm/assembler.h>
  12
  13                 .macro  pack, rd, hw1, hw2
  14 #ifndef __ARMEB__
  15                 orr     \rd, \hw1, \hw2, lsl #16
  16 #else
  17                 orr     \rd, \hw2, \hw1, lsl #16
  18 #endif
  19                 .endm
  20
  21 .Linsw_align:   movs    ip, r1, lsl #31
  22                 bne     .Linsw_noalign
  23                 ldrh    ip, [r0]
  24                 sub     r2, r2, #1
  25                 strh    ip, [r1], #2
  26
  27 ENTRY(__raw_readsw)
  28                 teq     r2, #0
  29                 moveq   pc, lr
  30                 tst     r1, #3
  31                 bne     .Linsw_align
  32
  33                 stmfd   sp!, {r4, r5, lr}
  34
  35                 subs    r2, r2, #8
  36                 bmi     .Lno_insw_8
  37
  38 .Linsw_8_lp:    ldrh    r3, [r0]
  39                 ldrh    r4, [r0]
  40                 pack    r3, r3, r4
  41
  42                 ldrh    r4, [r0]
  43                 ldrh    r5, [r0]
  44                 pack    r4, r4, r5
  45
  46                 ldrh    r5, [r0]
  47                 ldrh    ip, [r0]
  48                 pack    r5, r5, ip
  49
  50                 ldrh    ip, [r0]
  51                 ldrh    lr, [r0]
  52                 pack    ip, ip, lr
  53
  54                 subs    r2, r2, #8
  55                 stmia   r1!, {r3 - r5, ip}
  56                 bpl     .Linsw_8_lp
  57
  58 .Lno_insw_8:    tst     r2, #4
  59                 beq     .Lno_insw_4
  60
  61                 ldrh    r3, [r0]
  62                 ldrh    r4, [r0]
  63                 pack    r3, r3, r4
  64
  65                 ldrh    r4, [r0]
  66                 ldrh    ip, [r0]
  67                 pack    r4, r4, ip
  68
  69                 stmia   r1!, {r3, r4}
  70
  71 .Lno_insw_4:    movs    r2, r2, lsl #31
  72                 bcc     .Lno_insw_2
  73
  74                 ldrh    r3, [r0]
  75                 ldrh    ip, [r0]
  76                 pack    r3, r3, ip
  77                 str     r3, [r1], #4
  78
  79 .Lno_insw_2:    ldrneh  r3, [r0]
  80                 strneh  r3, [r1]
  81
  82                 ldmfd   sp!, {r4, r5, pc}
  83
  84 #ifdef __ARMEB__
  85 #define _BE_ONLY_(code...)      code
  86 #define _LE_ONLY_(code...)
  87 #define push_hbyte0             lsr #8
  88 #define pull_hbyte1             lsl #24
  89 #else
  90 #define _BE_ONLY_(code...)
  91 #define _LE_ONLY_(code...) code
  92 #define push_hbyte0             lsl #24
  93 #define pull_hbyte1             lsr #8
  94 #endif
  95
  96 .Linsw_noalign: stmfd   sp!, {r4, lr}
  97                 ldrccb  ip, [r1, #-1]!
  98                 bcc     1f
  99
 100                 ldrh    ip, [r0]
 101                 sub     r2, r2, #1
 102    _BE_ONLY_(   mov     ip, ip, ror #8          )
 103                 strb    ip, [r1], #1
 104    _LE_ONLY_(   mov     ip, ip, lsr #8          )
 105    _BE_ONLY_(   mov     ip, ip, lsr #24         )
 106
 107 1:              subs    r2, r2, #2
 108                 bmi     3f
 109    _BE_ONLY_(   mov     ip, ip, lsl #24         )
 110
 111 2:              ldrh    r3, [r0]
 112                 ldrh    r4, [r0]
 113                 subs    r2, r2, #2
 114                 orr     ip, ip, r3, lsl #8
 115                 orr     ip, ip, r4, push_hbyte0
 116                 str     ip, [r1], #4
 117                 mov     ip, r4, pull_hbyte1
 118                 bpl     2b
 119
 120    _BE_ONLY_(   mov     ip, ip, lsr #24         )
 121
 122 3:              tst     r2, #1
 123                 strb    ip, [r1], #1
 124                 ldrneh  ip, [r0]
 125    _BE_ONLY_(   movne   ip, ip, ror #8          )
 126                 strneb  ip, [r1], #1
 127    _LE_ONLY_(   movne   ip, ip, lsr #8          )
 128    _BE_ONLY_(   movne   ip, ip, lsr #24         )
 129                 strneb  ip, [r1]
 130                 ldmfd   sp!, {r4, pc}
 131 ENDPROC(__raw_readsw)