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   1 /*
   2  *  linux/arch/arm/lib/io-readsb.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 .Linsb_align:   rsb     ip, ip, #4
  14                 cmp     ip, r2
  15                 movgt   ip, r2
  16                 cmp     ip, #2
  17                 ldrb    r3, [r0]
  18                 strb    r3, [r1], #1
  19                 ldrgeb  r3, [r0]
  20                 strgeb  r3, [r1], #1
  21                 ldrgtb  r3, [r0]
  22                 strgtb  r3, [r1], #1
  23                 subs    r2, r2, ip
  24                 bne     .Linsb_aligned
  25
  26 ENTRY(__raw_readsb)
  27                 teq     r2, #0          @ do we have to check for the zero len?
  28                 moveq   pc, lr
  29                 ands    ip, r1, #3
  30                 bne     .Linsb_align
  31
  32 .Linsb_aligned: stmfd   sp!, {r4 - r6, lr}
  33
  34                 subs    r2, r2, #16
  35                 bmi     .Linsb_no_16
  36
  37 .Linsb_16_lp:   ldrb    r3, [r0]
  38                 ldrb    r4, [r0]
  39                 ldrb    r5, [r0]
  40                 mov     r3, r3,     put_byte_0
  41                 ldrb    r6, [r0]
  42                 orr     r3, r3, r4, put_byte_1
  43                 ldrb    r4, [r0]
  44                 orr     r3, r3, r5, put_byte_2
  45                 ldrb    r5, [r0]
  46                 orr     r3, r3, r6, put_byte_3
  47                 ldrb    r6, [r0]
  48                 mov     r4, r4,     put_byte_0
  49                 ldrb    ip, [r0]
  50                 orr     r4, r4, r5, put_byte_1
  51                 ldrb    r5, [r0]
  52                 orr     r4, r4, r6, put_byte_2
  53                 ldrb    r6, [r0]
  54                 orr     r4, r4, ip, put_byte_3
  55                 ldrb    ip, [r0]
  56                 mov     r5, r5,     put_byte_0
  57                 ldrb    lr, [r0]
  58                 orr     r5, r5, r6, put_byte_1
  59                 ldrb    r6, [r0]
  60                 orr     r5, r5, ip, put_byte_2
  61                 ldrb    ip, [r0]
  62                 orr     r5, r5, lr, put_byte_3
  63                 ldrb    lr, [r0]
  64                 mov     r6, r6,     put_byte_0
  65                 orr     r6, r6, ip, put_byte_1
  66                 ldrb    ip, [r0]
  67                 orr     r6, r6, lr, put_byte_2
  68                 orr     r6, r6, ip, put_byte_3
  69                 stmia   r1!, {r3 - r6}
  70
  71                 subs    r2, r2, #16
  72                 bpl     .Linsb_16_lp
  73
  74                 tst     r2, #15
  75                 ldmeqfd sp!, {r4 - r6, pc}
  76
  77 .Linsb_no_16:   tst     r2, #8
  78                 beq     .Linsb_no_8
  79
  80                 ldrb    r3, [r0]
  81                 ldrb    r4, [r0]
  82                 ldrb    r5, [r0]
  83                 mov     r3, r3,     put_byte_0
  84                 ldrb    r6, [r0]
  85                 orr     r3, r3, r4, put_byte_1
  86                 ldrb    r4, [r0]
  87                 orr     r3, r3, r5, put_byte_2
  88                 ldrb    r5, [r0]
  89                 orr     r3, r3, r6, put_byte_3
  90                 ldrb    r6, [r0]
  91                 mov     r4, r4,     put_byte_0
  92                 ldrb    ip, [r0]
  93                 orr     r4, r4, r5, put_byte_1
  94                 orr     r4, r4, r6, put_byte_2
  95                 orr     r4, r4, ip, put_byte_3
  96                 stmia   r1!, {r3, r4}
  97
  98 .Linsb_no_8:    tst     r2, #4
  99                 beq     .Linsb_no_4
 100
 101                 ldrb    r3, [r0]
 102                 ldrb    r4, [r0]
 103                 ldrb    r5, [r0]
 104                 ldrb    r6, [r0]
 105                 mov     r3, r3,     put_byte_0
 106                 orr     r3, r3, r4, put_byte_1
 107                 orr     r3, r3, r5, put_byte_2
 108                 orr     r3, r3, r6, put_byte_3
 109                 str     r3, [r1], #4
 110
 111 .Linsb_no_4:    ands    r2, r2, #3
 112                 ldmeqfd sp!, {r4 - r6, pc}
 113
 114                 cmp     r2, #2
 115                 ldrb    r3, [r0]
 116                 strb    r3, [r1], #1
 117                 ldrgeb  r3, [r0]
 118                 strgeb  r3, [r1], #1
 119                 ldrgtb  r3, [r0]
 120                 strgtb  r3, [r1]
 121
 122                 ldmfd   sp!, {r4 - r6, pc}
 123 ENDPROC(__raw_readsb)