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