WebSVN – freemyipod – Diff – /emcore/trunk/arm/memmove-arm.S

 /***************************************************************************
  *             __________               __   ___.
  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
  *                     \/            \/     \/    \/            \/
  * $Id$
  *
  * Copyright (C) 2006 Free Software Foundation, Inc.
  * This file was originally part of the GNU C Library
  * Contributed to glibc by MontaVista Software, Inc. (written by Nicolas Pitre)
  * Adapted for Rockbox by Daniel Ankers
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * as published by the Free Software Foundation; either version 2
  * of the License, or (at your option) any later version.
  *
  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  * KIND, either express or implied.
  *
  ****************************************************************************/
 #define ASM_FILE
 #include "global.h"
 /* ARMv4T doesn't switch the T bit when popping pc directly, we must use BX */
 .macro ldmpc cond="", order="ia", regs
 #if ARM_ARCH == 4 && defined(USE_THUMB)
     ldm\cond\order sp!, { \regs, lr }
     bx\cond lr
 #else
     ldm\cond\order sp!, { \regs, pc }
 #endif
 .endm
 .macro ldrpc cond=""
 #if ARM_ARCH == 4 && defined(USE_THUMB)
     ldr\cond lr, [sp], #4
     bx\cond  lr
 #else
     ldr\cond pc, [sp], #4
 #endif
 .endm
 /*
  * Endian independent macros for shifting bytes within registers.
  */
 #ifndef __ARMEB__
 #define pull            lsr
 #define push            lsl
 #else
 #define pull            lsl
 #define push            lsr
 #endif
         .text
 /*
  * Prototype: void *memmove(void *dest, const void *src, size_t n);
  *
  * Note:
  *
  * If the memory regions don't overlap, we simply branch to memcpy which is
  * normally a bit faster. Otherwise the copy is done going downwards.
  */
     .section    .icode,"ax",%progbits
     .align      2
     .global     memmove
     .type       memmove,%function
 memmove:
         subs    ip, r0, r1
         cmphi   r2, ip
         bls memcpy
         stmfd   sp!, {r0, r4, lr}
         add r1, r1, r2
         add r0, r0, r2
         subs    r2, r2, #4
         blt 8f
         ands    ip, r0, #3
         bne 9f
         ands    ip, r1, #3
         bne 10f
 :      subs    r2, r2, #(28)
         stmfd   sp!, {r5 - r8}
         blt 5f
 :
 :
 :      ldmdb   r1!, {r3, r4, r5, r6, r7, r8, ip, lr}
         subs    r2, r2, #32
         stmdb   r0!, {r3, r4, r5, r6, r7, r8, ip, lr}
         bge 3b
 :      ands    ip, r2, #28
         rsb ip, ip, #32
         addne   pc, pc, ip      @ C is always clear here
         b   7f
 :      nop
         ldr r3, [r1, #-4]!
         ldr r4, [r1, #-4]!
         ldr r5, [r1, #-4]!
         ldr r6, [r1, #-4]!
         ldr r7, [r1, #-4]!
         ldr r8, [r1, #-4]!
         ldr lr, [r1, #-4]!
         add pc, pc, ip
         nop
         nop
         str r3, [r0, #-4]!
         str r4, [r0, #-4]!
         str r5, [r0, #-4]!
         str r6, [r0, #-4]!
         str r7, [r0, #-4]!
         str r8, [r0, #-4]!
         str lr, [r0, #-4]!
 :      ldmfd   sp!, {r5 - r8}
 :      movs    r2, r2, lsl #31
         ldrneb  r3, [r1, #-1]!
         ldrcsb  r4, [r1, #-1]!
         ldrcsb  ip, [r1, #-1]
         strneb  r3, [r0, #-1]!
         strcsb  r4, [r0, #-1]!
         strcsb  ip, [r0, #-1]
         ldmpc   regs="r0, r4"
 :      cmp ip, #2
         ldrgtb  r3, [r1, #-1]!
         ldrgeb  r4, [r1, #-1]!
         ldrb    lr, [r1, #-1]!
         strgtb  r3, [r0, #-1]!
         strgeb  r4, [r0, #-1]!
         subs    r2, r2, ip
         strb    lr, [r0, #-1]!
         blt 8b
         ands    ip, r1, #3
         beq 1b
 :     bic r1, r1, #3
         cmp ip, #2
         ldr r3, [r1, #0]
         beq 17f
         blt 18f
         .macro  backward_copy_shift push pull
         subs    r2, r2, #28
         blt 14f
 :     stmfd   sp!, {r5 - r9}
 :
 :     ldmdb   r1!, {r7, r8, r9, ip}
         mov     lr, r3, push #\push
         subs    r2, r2, #32
         ldmdb   r1!, {r3, r4, r5, r6}
         orr     lr, lr, ip, pull #\pull
         mov     ip, ip, push #\push
         orr     ip, ip, r9, pull #\pull
         mov     r9, r9, push #\push
         orr     r9, r9, r8, pull #\pull
         mov     r8, r8, push #\push
         orr     r8, r8, r7, pull #\pull
         mov     r7, r7, push #\push
         orr     r7, r7, r6, pull #\pull
         mov     r6, r6, push #\push
         orr     r6, r6, r5, pull #\pull
         mov     r5, r5, push #\push
         orr     r5, r5, r4, pull #\pull
         mov     r4, r4, push #\push
         orr     r4, r4, r3, pull #\pull
         stmdb   r0!, {r4 - r9, ip, lr}
         bge 12b
         ldmfd   sp!, {r5 - r9}
 :     ands    ip, r2, #28
         beq 16f
 :     mov     lr, r3, push #\push
         ldr r3, [r1, #-4]!
         subs    ip, ip, #4
         orr lr, lr, r3, pull #\pull
         str lr, [r0, #-4]!
         bgt 15b
 :     add r1, r1, #(\pull / 8)
         b   8b
         .endm
         backward_copy_shift push=8  pull=24
 :     backward_copy_shift push=16 pull=16
 :     backward_copy_shift push=24 pull=8

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