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
  26 memcpy:
  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
  47 0:      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
  54 memcpy_2:
  55         setlos          #2,gr11
  56         sub.p           gr8,gr11,gr3
  57         sub             gr9,gr11,gr9
  58 0:      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
  65 memcpy_4:
  66         setlos          #4,gr11
  67         sub.p           gr8,gr11,gr3
  68         sub             gr9,gr11,gr9
  69 0:      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
  76 memcpy_8:
  77         sub.p           gr8,gr11,gr3
  78         sub             gr9,gr11,gr9
  79 0:      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
  86 memcpy_16:
  87         sub.p           gr8,gr11,gr3
  88         sub             gr9,gr11,gr9
  89 0:      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