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   1 /* memset.S: optimised assembly memset
   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 *memset(void *p, char ch, 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 set
  22 #         GR4, GR7, GR8, and GR11 must be managed
  23 #
  24 ###############################################################################
  25         .globl          memset,__memset_end
  26         .type           memset,@function
  27 memset:
  28         orcc.p          gr10,gr0,gr5,icc3               ; GR5 = count
  29         andi            gr9,#0xff,gr9
  30         or.p            gr8,gr0,gr4                     ; GR4 = address
  31         beqlr           icc3,#0
  32
  33         # conditionally write a byte to 2b-align the address
  34         setlos.p        #1,gr6
  35         andicc          gr4,#1,gr0,icc0
  36         ckne            icc0,cc7
  37         cstb.p          gr9,@(gr4,gr0)          ,cc7,#1
  38         csubcc          gr5,gr6,gr5             ,cc7,#1 ; also set ICC3
  39         cadd.p          gr4,gr6,gr4             ,cc7,#1
  40         beqlr           icc3,#0
  41
  42         # conditionally write a word to 4b-align the address
  43         andicc.p        gr4,#2,gr0,icc0
  44         subicc          gr5,#2,gr0,icc1
  45         setlos.p        #2,gr6
  46         ckne            icc0,cc7
  47         slli.p          gr9,#8,gr12                     ; need to double up the pattern
  48         cknc            icc1,cc5
  49         or.p            gr9,gr12,gr12
  50         andcr           cc7,cc5,cc7
  51
  52         csth.p          gr12,@(gr4,gr0)         ,cc7,#1
  53         csubcc          gr5,gr6,gr5             ,cc7,#1 ; also set ICC3
  54         cadd.p          gr4,gr6,gr4             ,cc7,#1
  55         beqlr           icc3,#0
  56
  57         # conditionally write a dword to 8b-align the address
  58         andicc.p        gr4,#4,gr0,icc0
  59         subicc          gr5,#4,gr0,icc1
  60         setlos.p        #4,gr6
  61         ckne            icc0,cc7
  62         slli.p          gr12,#16,gr13                   ; need to quadruple-up the pattern
  63         cknc            icc1,cc5
  64         or.p            gr13,gr12,gr12
  65         andcr           cc7,cc5,cc7
  66
  67         cst.p           gr12,@(gr4,gr0)         ,cc7,#1
  68         csubcc          gr5,gr6,gr5             ,cc7,#1 ; also set ICC3
  69         cadd.p          gr4,gr6,gr4             ,cc7,#1
  70         beqlr           icc3,#0
  71
  72         or.p            gr12,gr12,gr13                  ; need to octuple-up the pattern
  73
  74         # the address is now 8b-aligned - loop around writing 64b chunks
  75         setlos          #8,gr7
  76         subi.p          gr4,#8,gr4                      ; store with update index does weird stuff
  77         setlos          #64,gr6
  78
  79         subicc          gr5,#64,gr0,icc0
  80 0:      cknc            icc0,cc7
  81         cstdu           gr12,@(gr4,gr7)         ,cc7,#1
  82         cstdu           gr12,@(gr4,gr7)         ,cc7,#1
  83         cstdu           gr12,@(gr4,gr7)         ,cc7,#1
  84         cstdu           gr12,@(gr4,gr7)         ,cc7,#1
  85         cstdu           gr12,@(gr4,gr7)         ,cc7,#1
  86         cstdu.p         gr12,@(gr4,gr7)         ,cc7,#1
  87         csubcc          gr5,gr6,gr5             ,cc7,#1 ; also set ICC3
  88         cstdu.p         gr12,@(gr4,gr7)         ,cc7,#1
  89         subicc          gr5,#64,gr0,icc0
  90         cstdu.p         gr12,@(gr4,gr7)         ,cc7,#1
  91         beqlr           icc3,#0
  92         bnc             icc0,#2,0b
  93
  94         # now do 32-byte remnant
  95         subicc.p        gr5,#32,gr0,icc0
  96         setlos          #32,gr6
  97         cknc            icc0,cc7
  98         cstdu.p         gr12,@(gr4,gr7)         ,cc7,#1
  99         csubcc          gr5,gr6,gr5             ,cc7,#1 ; also set ICC3
 100         cstdu.p         gr12,@(gr4,gr7)         ,cc7,#1
 101         setlos          #16,gr6
 102         cstdu.p         gr12,@(gr4,gr7)         ,cc7,#1
 103         subicc          gr5,#16,gr0,icc0
 104         cstdu.p         gr12,@(gr4,gr7)         ,cc7,#1
 105         beqlr           icc3,#0
 106
 107         # now do 16-byte remnant
 108         cknc            icc0,cc7
 109         cstdu.p         gr12,@(gr4,gr7)         ,cc7,#1
 110         csubcc          gr5,gr6,gr5             ,cc7,#1 ; also set ICC3
 111         cstdu.p         gr12,@(gr4,gr7)         ,cc7,#1
 112         beqlr           icc3,#0
 113
 114         # now do 8-byte remnant
 115         subicc          gr5,#8,gr0,icc1
 116         cknc            icc1,cc7
 117         cstdu.p         gr12,@(gr4,gr7)         ,cc7,#1
 118         csubcc          gr5,gr7,gr5             ,cc7,#1 ; also set ICC3
 119         setlos.p        #4,gr7
 120         beqlr           icc3,#0
 121
 122         # now do 4-byte remnant
 123         subicc          gr5,#4,gr0,icc0
 124         addi.p          gr4,#4,gr4
 125         cknc            icc0,cc7
 126         cstu.p          gr12,@(gr4,gr7)         ,cc7,#1
 127         csubcc          gr5,gr7,gr5             ,cc7,#1 ; also set ICC3
 128         subicc.p        gr5,#2,gr0,icc1
 129         beqlr           icc3,#0
 130
 131         # now do 2-byte remnant
 132         setlos          #2,gr7
 133         addi.p          gr4,#2,gr4
 134         cknc            icc1,cc7
 135         csthu.p         gr12,@(gr4,gr7)         ,cc7,#1
 136         csubcc          gr5,gr7,gr5             ,cc7,#1 ; also set ICC3
 137         subicc.p        gr5,#1,gr0,icc0
 138         beqlr           icc3,#0
 139
 140         # now do 1-byte remnant
 141         setlos          #0,gr7
 142         addi.p          gr4,#2,gr4
 143         cknc            icc0,cc7
 144         cstb.p          gr12,@(gr4,gr0)         ,cc7,#1
 145         bralr
 146 __memset_end:
 147
 148         .size           memset, __memset_end-memset
 149
 150 ###############################################################################
 151 #
 152 # clear memory in userspace
 153 # - return the number of bytes that could not be cleared (0 on complete success)
 154 #
 155 # long __memset_user(void *p, size_t count)
 156 #
 157 ###############################################################################
 158         .globl          __memset_user, __memset_user_error_lr, __memset_user_error_handler
 159         .type           __memset_user,@function
 160 __memset_user:
 161         movsg           lr,gr11
 162
 163         # abuse memset to do the dirty work
 164         or.p            gr9,gr9,gr10
 165         setlos          #0,gr9
 166         call            memset
 167 __memset_user_error_lr:
 168         jmpl.p          @(gr11,gr0)
 169         setlos          #0,gr8
 170
 171         # deal any exception generated by memset
 172         # GR4  - memset's address tracking pointer
 173         # GR7  - memset's step value (index register for store insns)
 174         # GR8  - memset's original start address
 175         # GR10 - memset's original count
 176 __memset_user_error_handler:
 177         add.p           gr4,gr7,gr4
 178         add             gr8,gr10,gr8
 179         jmpl.p          @(gr11,gr0)
 180         sub             gr8,gr4,gr8             ; we return the amount left uncleared
 181
 182         .size           __memset_user, .-__memset_user