firmware/target/arm/memcpy-arm.S

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2006 Free Software Foundation, Inc.
  11  * This file was originally part of the GNU C Library
  12  * Contributed to glibc by MontaVista Software, Inc. (written by Nicolas Pitre)
  13  * Adapted for Rockbox by Daniel Ankers
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License
  17  * as published by the Free Software Foundation; either version 2
  18  * of the License, or (at your option) any later version.
  19  *
  20  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  21  * KIND, either express or implied.
  22  *
  23  ****************************************************************************/
  24
  25 #include "config.h"
  26
  27 /*
  28  * Endian independent macros for shifting bytes within registers.
  29  */
  30 #ifndef __ARMEB__
  31 #define pull            lsr
  32 #define push            lsl
  33 #else
  34 #define pull            lsl
  35 #define push            lsr
  36 #endif
  37
  38 /* Prototype: void *memcpy(void *dest, const void *src, size_t n); */
  39
  40     .section    .icode,"ax",%progbits
  41
  42     .align      2
  43     .global     memcpy
  44     .type       memcpy,%function
  45
  46 memcpy:
  47                 stmfd   sp!, {r0, r4, lr}
  48
  49                 subs    r2, r2, #4
  50                 blt     8f
  51                 ands    ip, r0, #3
  52                 bne     9f
  53                 ands    ip, r1, #3
  54                 bne     10f
  55
  56 1:              subs    r2, r2, #(28)
  57                 stmfd   sp!, {r5 - r8}
  58                 blt     5f
  59
  60 2:
  61 3:
  62 4:              ldmia   r1!, {r3, r4, r5, r6, r7, r8, ip, lr}
  63                 subs    r2, r2, #32
  64                 stmia   r0!, {r3, r4, r5, r6, r7, r8, ip, lr}
  65                 bge     3b
  66
  67 5:              ands    ip, r2, #28
  68                 rsb     ip, ip, #32
  69                 addne   pc, pc, ip              @ C is always clear here
  70                 b       7f
  71 6:              nop
  72                 ldr     r3, [r1], #4
  73                 ldr     r4, [r1], #4
  74                 ldr     r5, [r1], #4
  75                 ldr     r6, [r1], #4
  76                 ldr     r7, [r1], #4
  77                 ldr     r8, [r1], #4
  78                 ldr     lr, [r1], #4
  79
  80                 add     pc, pc, ip
  81                 nop
  82                 nop
  83                 str     r3, [r0], #4
  84                 str     r4, [r0], #4
  85                 str     r5, [r0], #4
  86                 str     r6, [r0], #4
  87                 str     r7, [r0], #4
  88                 str     r8, [r0], #4
  89                 str     lr, [r0], #4
  90
  91 7:              ldmfd   sp!, {r5 - r8}
  92
  93 8:              movs    r2, r2, lsl #31
  94                 ldrneb  r3, [r1], #1
  95                 ldrcsb  r4, [r1], #1
  96                 ldrcsb  ip, [r1]
  97                 strneb  r3, [r0], #1
  98                 strcsb  r4, [r0], #1
  99                 strcsb  ip, [r0]
 100
 101                 ldmfd   sp!, {r0, r4, pc}
 102
 103 9:              rsb     ip, ip, #4
 104                 cmp     ip, #2
 105                 ldrgtb  r3, [r1], #1
 106                 ldrgeb  r4, [r1], #1
 107                 ldrb    lr, [r1], #1
 108                 strgtb  r3, [r0], #1
 109                 strgeb  r4, [r0], #1
 110                 subs    r2, r2, ip
 111                 strb    lr, [r0], #1
 112                 blt     8b
 113                 ands    ip, r1, #3
 114                 beq     1b
 115
 116 10:             bic     r1, r1, #3
 117                 cmp     ip, #2
 118                 ldr     lr, [r1], #4
 119                 beq     17f
 120                 bgt     18f
 121
 122
 123                 .macro  forward_copy_shift pull push
 124
 125                 subs    r2, r2, #28
 126                 blt     14f
 127
 128 11:             stmfd   sp!, {r5 - r9}
 129
 130 12:
 131 13:             ldmia   r1!, {r4, r5, r6, r7}
 132                 mov     r3, lr, pull #\pull
 133                 subs    r2, r2, #32
 134                 ldmia   r1!, {r8, r9, ip, lr}
 135                 orr     r3, r3, r4, push #\push
 136                 mov     r4, r4, pull #\pull
 137                 orr     r4, r4, r5, push #\push
 138                 mov     r5, r5, pull #\pull
 139                 orr     r5, r5, r6, push #\push
 140                 mov     r6, r6, pull #\pull
 141                 orr     r6, r6, r7, push #\push
 142                 mov     r7, r7, pull #\pull
 143                 orr     r7, r7, r8, push #\push
 144                 mov     r8, r8, pull #\pull
 145                 orr     r8, r8, r9, push #\push
 146                 mov     r9, r9, pull #\pull
 147                 orr     r9, r9, ip, push #\push
 148                 mov     ip, ip, pull #\pull
 149                 orr     ip, ip, lr, push #\push
 150                 stmia   r0!, {r3, r4, r5, r6, r7, r8, r9, ip}
 151                 bge     12b
 152
 153                 ldmfd   sp!, {r5 - r9}
 154
 155 14:             ands    ip, r2, #28
 156                 beq     16f
 157
 158 15:             mov     r3, lr, pull #\pull
 159                 ldr     lr, [r1], #4
 160                 subs    ip, ip, #4
 161                 orr     r3, r3, lr, push #\push
 162                 str     r3, [r0], #4
 163                 bgt     15b
 164
 165 16:             sub     r1, r1, #(\push / 8)
 166                 b       8b
 167
 168                 .endm
 169
 170
 171                 forward_copy_shift      pull=8  push=24
 172
 173 17:             forward_copy_shift      pull=16 push=16
 174
 175 18:             forward_copy_shift      pull=24 push=8
 176