arch/unicore32/lib/copy_template.S

   1 /*
   2  * linux/arch/unicore32/lib/copy_template.S
   3  *
   4  * Code specific to PKUnity SoC and UniCore ISA
   5  *
   6  * Copyright (C) 2001-2010 GUAN Xue-tao
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 /*
  14  * Theory of operation
  15  * -------------------
  16  *
  17  * This file provides the core code for a forward memory copy used in
  18  * the implementation of memcopy(), copy_to_user() and copy_from_user().
  19  *
  20  * The including file must define the following accessor macros
  21  * according to the need of the given function:
  22  *
  23  * ldr1w ptr reg abort
  24  *
  25  *      This loads one word from 'ptr', stores it in 'reg' and increments
  26  *      'ptr' to the next word. The 'abort' argument is used for fixup tables.
  27  *
  28  * ldr4w ptr reg1 reg2 reg3 reg4 abort
  29  * ldr8w ptr, reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
  30  *
  31  *      This loads four or eight words starting from 'ptr', stores them
  32  *      in provided registers and increments 'ptr' past those words.
  33  *      The'abort' argument is used for fixup tables.
  34  *
  35  * ldr1b ptr reg cond abort
  36  *
  37  *      Similar to ldr1w, but it loads a byte and increments 'ptr' one byte.
  38  *      It also must apply the condition code if provided, otherwise the
  39  *      "al" condition is assumed by default.
  40  *
  41  * str1w ptr reg abort
  42  * str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
  43  * str1b ptr reg cond abort
  44  *
  45  *      Same as their ldr* counterparts, but data is stored to 'ptr' location
  46  *      rather than being loaded.
  47  *
  48  * enter
  49  *
  50  *      Preserve the provided registers on the stack plus any additional
  51  *      data as needed by the implementation including this code. Called
  52  *      upon code entry.
  53  *
  54  * exit
  55  *
  56  *      Restore registers with the values previously saved with the
  57  *      'preserv' macro. Called upon code termination.
  58  */
  59
  60
  61                 enter
  62
  63                 sub.a   r2, r2, #4
  64                 bsl     8f
  65                 and.a   ip, r0, #3
  66                 bne     9f
  67                 and.a   ip, r1, #3
  68                 bne     10f
  69
  70 1:              sub.a   r2, r2, #(28)
  71                 stm.w   (r5 - r8), [sp-]
  72                 bsl     5f
  73
  74 3:
  75 4:              ldr8w   r1, r3, r4, r5, r6, r7, r8, r10, r11, abort=20f
  76                 sub.a   r2, r2, #32
  77                 str8w   r0, r3, r4, r5, r6, r7, r8, r10, r11, abort=20f
  78                 beg     3b
  79
  80 5:              and.a   ip, r2, #28
  81                 rsub    ip, ip, #32
  82                 beq     7f
  83                 add     pc, pc, ip              @ C is always clear here
  84                 nop
  85
  86                 ldr1w   r1, r3, abort=20f
  87                 ldr1w   r1, r4, abort=20f
  88                 ldr1w   r1, r5, abort=20f
  89                 ldr1w   r1, r6, abort=20f
  90                 ldr1w   r1, r7, abort=20f
  91                 ldr1w   r1, r8, abort=20f
  92                 ldr1w   r1, r11, abort=20f
  93
  94                 add     pc, pc, ip
  95                 nop
  96
  97                 str1w   r0, r3, abort=20f
  98                 str1w   r0, r4, abort=20f
  99                 str1w   r0, r5, abort=20f
 100                 str1w   r0, r6, abort=20f
 101                 str1w   r0, r7, abort=20f
 102                 str1w   r0, r8, abort=20f
 103                 str1w   r0, r11, abort=20f
 104
 105 7:              ldm.w   (r5 - r8), [sp]+
 106
 107 8:              mov.a   r2, r2 << #31
 108                 ldr1b   r1, r3, ne, abort=21f
 109                 ldr1b   r1, r4, ea, abort=21f
 110                 ldr1b   r1, r10, ea, abort=21f
 111                 str1b   r0, r3, ne, abort=21f
 112                 str1b   r0, r4, ea, abort=21f
 113                 str1b   r0, r10, ea, abort=21f
 114
 115                 exit
 116
 117 9:              rsub    ip, ip, #4
 118                 csub.a  ip, #2
 119                 ldr1b   r1, r3, sg, abort=21f
 120                 ldr1b   r1, r4, eg, abort=21f
 121                 ldr1b   r1, r11, abort=21f
 122                 str1b   r0, r3, sg, abort=21f
 123                 str1b   r0, r4, eg, abort=21f
 124                 sub.a   r2, r2, ip
 125                 str1b   r0, r11, abort=21f
 126                 bsl     8b
 127                 and.a   ip, r1, #3
 128                 beq     1b
 129
 130 10:             andn    r1, r1, #3
 131                 csub.a  ip, #2
 132                 ldr1w   r1, r11, abort=21f
 133                 beq     17f
 134                 bsg     18f
 135
 136
 137                 .macro  forward_copy_shift a b
 138
 139                 sub.a   r2, r2, #28
 140                 bsl     14f
 141
 142 11:             stm.w   (r5 - r9), [sp-]
 143
 144 12:
 145                 ldr4w   r1, r4, r5, r6, r7, abort=19f
 146                 mov     r3, r11 pull #\a
 147                 sub.a   r2, r2, #32
 148                 ldr4w   r1, r8, r9, r10, r11, abort=19f
 149                 or      r3, r3, r4 push #\b
 150                 mov     r4, r4 pull #\a
 151                 or      r4, r4, r5 push #\b
 152                 mov     r5, r5 pull #\a
 153                 or      r5, r5, r6 push #\b
 154                 mov     r6, r6 pull #\a
 155                 or      r6, r6, r7 push #\b
 156                 mov     r7, r7 pull #\a
 157                 or      r7, r7, r8 push #\b
 158                 mov     r8, r8 pull #\a
 159                 or      r8, r8, r9 push #\b
 160                 mov     r9, r9 pull #\a
 161                 or      r9, r9, r10 push #\b
 162                 mov     r10, r10 pull #\a
 163                 or      r10, r10, r11 push #\b
 164                 str8w   r0, r3, r4, r5, r6, r7, r8, r9, r10, , abort=19f
 165                 beg     12b
 166
 167                 ldm.w   (r5 - r9), [sp]+
 168
 169 14:             and.a   ip, r2, #28
 170                 beq     16f
 171
 172 15:             mov     r3, r11 pull #\a
 173                 ldr1w   r1, r11, abort=21f
 174                 sub.a   ip, ip, #4
 175                 or      r3, r3, r11 push #\b
 176                 str1w   r0, r3, abort=21f
 177                 bsg     15b
 178
 179 16:             sub     r1, r1, #(\b / 8)
 180                 b       8b
 181
 182                 .endm
 183
 184
 185                 forward_copy_shift      a=8     b=24
 186
 187 17:             forward_copy_shift      a=16    b=16
 188
 189 18:             forward_copy_shift      a=24    b=8
 190
 191
 192 /*
 193  * Abort preamble and completion macros.
 194  * If a fixup handler is required then those macros must surround it.
 195  * It is assumed that the fixup code will handle the private part of
 196  * the exit macro.
 197  */
 198
 199         .macro  copy_abort_preamble
 200 19:     ldm.w   (r5 - r9), [sp]+
 201         b       21f
 202 299:    .word   0                       @ store lr
 203                                         @ to avoid function call in fixup
 204 20:     ldm.w   (r5 - r8), [sp]+
 205 21:
 206         adr     r1, 299b
 207         stw     lr, [r1]
 208         .endm
 209
 210         .macro  copy_abort_end
 211         adr     lr, 299b
 212         ldw     pc, [lr]
 213         .endm
 214