LXR linux/arch/frv/lib/memcpy.S

   1/* memcpy.S: optimised assembly memcpy
   2 *
   3 * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
   4 * Written by David Howells (dhowells@redhat.com)
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License
   8 * as published by the Free Software Foundation; either version
   9 * 2 of the License, or (at your option) any later version.
  10 */
  11
  12
  13        .text
  14        .p2align        4
  15
  16###############################################################################
  17#
  18# void *memcpy(void *to, const char *from, size_t count)
  19#
  20# - NOTE: must not use any stack. exception detection performs function return
  21#         to caller's fixup routine, aborting the remainder of the copy
  22#
  23###############################################################################
  24        .globl          memcpy,__memcpy_end
  25        .type           memcpy,@function
  26memcpy:
  27        or.p            gr8,gr9,gr4
  28        orcc            gr10,gr0,gr0,icc3
  29        or.p            gr10,gr4,gr4
  30        beqlr           icc3,#0
  31
  32        # optimise based on best common alignment for to, from & count
  33        andicc.p        gr4,#0x0f,gr0,icc0
  34        setlos          #8,gr11
  35        andicc.p        gr4,#0x07,gr0,icc1
  36        beq             icc0,#0,memcpy_16
  37        andicc.p        gr4,#0x03,gr0,icc0
  38        beq             icc1,#0,memcpy_8
  39        andicc.p        gr4,#0x01,gr0,icc1
  40        beq             icc0,#0,memcpy_4
  41        setlos.p        #1,gr11
  42        beq             icc1,#0,memcpy_2
  43
  44        # do byte by byte copy
  45        sub.p           gr8,gr11,gr3
  46        sub             gr9,gr11,gr9
  470:      ldubu.p         @(gr9,gr11),gr4
  48        subicc          gr10,#1,gr10,icc0
  49        stbu.p          gr4,@(gr3,gr11)
  50        bne             icc0,#2,0b
  51        bralr
  52
  53        # do halfword by halfword copy
  54memcpy_2:
  55        setlos          #2,gr11
  56        sub.p           gr8,gr11,gr3
  57        sub             gr9,gr11,gr9
  580:      lduhu.p         @(gr9,gr11),gr4
  59        subicc          gr10,#2,gr10,icc0
  60        sthu.p          gr4,@(gr3,gr11)
  61        bne             icc0,#2,0b
  62        bralr
  63
  64        # do word by word copy
  65memcpy_4:
  66        setlos          #4,gr11
  67        sub.p           gr8,gr11,gr3
  68        sub             gr9,gr11,gr9
  690:      ldu.p           @(gr9,gr11),gr4
  70        subicc          gr10,#4,gr10,icc0
  71        stu.p           gr4,@(gr3,gr11)
  72        bne             icc0,#2,0b
  73        bralr
  74
  75        # do double-word by double-word copy
  76memcpy_8:
  77        sub.p           gr8,gr11,gr3
  78        sub             gr9,gr11,gr9
  790:      lddu.p          @(gr9,gr11),gr4
  80        subicc          gr10,#8,gr10,icc0
  81        stdu.p          gr4,@(gr3,gr11)
  82        bne             icc0,#2,0b
  83        bralr
  84
  85        # do quad-word by quad-word copy
  86memcpy_16:
  87        sub.p           gr8,gr11,gr3
  88        sub             gr9,gr11,gr9
  890:      lddu            @(gr9,gr11),gr4
  90        lddu.p          @(gr9,gr11),gr6
  91        subicc          gr10,#16,gr10,icc0
  92        stdu            gr4,@(gr3,gr11)
  93        stdu.p          gr6,@(gr3,gr11)
  94        bne             icc0,#2,0b
  95        bralr
  96__memcpy_end:
  97
  98        .size           memcpy, __memcpy_end-memcpy
  99
 100###############################################################################
 101#
 102# copy to/from userspace
 103# - return the number of bytes that could not be copied (0 on complete success)
 104#
 105# long __memcpy_user(void *dst, const void *src, size_t count)
 106#
 107###############################################################################
 108        .globl          __memcpy_user, __memcpy_user_error_lr, __memcpy_user_error_handler
 109        .type           __memcpy_user,@function
 110__memcpy_user:
 111        movsg           lr,gr7
 112        subi.p          sp,#8,sp
 113        add             gr8,gr10,gr6            ; calculate expected end address
 114        stdi            gr6,@(sp,#0)
 115
 116        # abuse memcpy to do the dirty work
 117        call            memcpy
 118__memcpy_user_error_lr:
 119        ldi.p           @(sp,#4),gr7
 120        setlos          #0,gr8
 121        jmpl.p          @(gr7,gr0)
 122        addi            sp,#8,sp
 123
 124        # deal any exception generated by memcpy
 125        # GR8 - memcpy's current dest address
 126        # GR11 - memset's step value (index register for store insns)
 127__memcpy_user_error_handler:
 128        lddi.p          @(sp,#0),gr4            ; load GR4 with dst+count, GR5 with ret addr
 129        add             gr11,gr3,gr7
 130        sub.p           gr4,gr7,gr8
 131
 132        addi            sp,#8,sp
 133        jmpl            @(gr5,gr0)
 134
 135        .size           __memcpy_user, .-__memcpy_user
 136