kernel/arch/score/lib/checksum.S

   1 /*
   2  * arch/score/lib/csum_partial.S
   3  *
   4  * Score Processor version.
   5  *
   6  * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
   7  *  Lennox Wu <lennox.wu@sunplusct.com>
   8  *  Chen Liqin <liqin.chen@sunplusct.com>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, see the file COPYING, or write
  22  * to the Free Software Foundation, Inc.,
  23  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  24  */
  25 #include <linux/linkage.h>
  26
  27 #define ADDC(sum,reg)                   \
  28         add     sum, sum, reg;          \
  29         cmp.c   reg, sum;               \
  30         bleu    9f;                     \
  31         addi    sum, 0x1;               \
  32 9:
  33
  34 #define CSUM_BIGCHUNK(src, offset, sum)         \
  35         lw      r8, [src, offset + 0x00];       \
  36         lw      r9, [src, offset + 0x04];       \
  37         lw      r10, [src, offset + 0x08];      \
  38         lw      r11, [src, offset + 0x0c];      \
  39         ADDC(sum, r8);                          \
  40         ADDC(sum, r9);                          \
  41         ADDC(sum, r10);                         \
  42         ADDC(sum, r11);                         \
  43         lw      r8, [src, offset + 0x10];       \
  44         lw      r9, [src, offset + 0x14];       \
  45         lw      r10, [src, offset + 0x18];      \
  46         lw      r11, [src, offset + 0x1c];      \
  47         ADDC(sum, r8);                          \
  48         ADDC(sum, r9);                          \
  49         ADDC(sum, r10);                         \
  50         ADDC(sum, r11);                         \
  51
  52 #define src r4
  53 #define dest r5
  54 #define sum r27
  55
  56         .text
  57 /* unknown src alignment and < 8 bytes to go */
  58 small_csumcpy:
  59         mv      r5, r10
  60         ldi     r9, 0x0
  61         cmpi.c  r25, 0x1
  62         beq pass_small_set_t7   /*already set, jump to pass_small_set_t7*/
  63         andri.c r25,r4 , 0x1    /*Is src 2 bytes aligned?*/
  64
  65 pass_small_set_t7:
  66         beq     aligned
  67         cmpi.c  r5, 0x0
  68         beq     fold
  69         lbu     r9, [src]
  70         slli    r9,r9, 0x8      /*Little endian*/
  71         ADDC(sum, r9)
  72         addi    src, 0x1
  73         subi.c  r5, 0x1
  74
  75         /*len still a full word */
  76 aligned:
  77         andri.c r8, r5, 0x4     /*Len >= 4?*/
  78         beq     len_less_4bytes
  79
  80         /* Still a full word (4byte) to go,and the src is word aligned.*/
  81         andri.c r8, src, 0x3    /*src is 4bytes aligned, so use LW!!*/
  82         beq     four_byte_aligned
  83         lhu     r9, [src]
  84         addi    src, 2
  85         ADDC(sum, r9)
  86         lhu     r9, [src]
  87         addi    src, 2
  88         ADDC(sum, r9)
  89         b len_less_4bytes
  90
  91 four_byte_aligned:              /* Len >=4 and four byte aligned */
  92         lw      r9, [src]
  93         addi    src, 4
  94         ADDC(sum, r9)
  95
  96 len_less_4bytes:                /* 2 byte aligned aligned and length<4B */
  97         andri.c r8, r5, 0x2
  98         beq     len_less_2bytes
  99         lhu     r9, [src]
 100         addi    src, 0x2        /* src+=2 */
 101         ADDC(sum, r9)
 102
 103 len_less_2bytes:                /* len = 1 */
 104         andri.c r8, r5, 0x1
 105         beq     fold            /* less than 2 and not equal 1--> len=0 -> fold */
 106         lbu     r9, [src]
 107
 108 fold_ADDC:
 109         ADDC(sum, r9)
 110 fold:
 111         /* fold checksum */
 112         slli    r26, sum, 16
 113         add     sum, sum, r26
 114         cmp.c   r26, sum
 115         srli    sum, sum, 16
 116         bleu    1f              /* if r26<=sum */
 117         addi    sum, 0x1        /* r26>sum */
 118 1:
 119         /* odd buffer alignment? r25 was set in csum_partial */
 120         cmpi.c  r25, 0x0
 121         beq     1f
 122         slli    r26, sum, 8
 123         srli    sum, sum, 8
 124         or      sum, sum, r26
 125         andi    sum, 0xffff
 126 1:
 127         .set    optimize
 128         /* Add the passed partial csum. */
 129         ADDC(sum, r6)
 130         mv      r4, sum
 131         br      r3
 132         .set    volatile
 133
 134         .align  5
 135 ENTRY(csum_partial)
 136         ldi sum, 0
 137         ldi r25, 0
 138         mv r10, r5
 139         cmpi.c  r5, 0x8
 140         blt     small_csumcpy           /* < 8(signed) bytes to copy */
 141         cmpi.c  r5, 0x0
 142         beq     out
 143         andri.c r25, src, 0x1           /* odd buffer? */
 144
 145         beq     word_align
 146 hword_align:                            /* 1 byte */
 147         lbu     r8, [src]
 148         subi    r5, 0x1
 149         slli    r8, r8, 8
 150         ADDC(sum, r8)
 151         addi    src, 0x1
 152
 153 word_align:                             /* 2 bytes */
 154         andri.c r8, src, 0x2            /* 4bytes(dword)_aligned? */
 155         beq     dword_align             /* not, maybe dword_align */
 156         lhu     r8, [src]
 157         subi    r5, 0x2
 158         ADDC(sum, r8)
 159         addi    src, 0x2
 160
 161 dword_align:                            /* 4bytes */
 162         mv      r26, r5                 /* maybe useless when len >=56 */
 163         ldi     r8, 56
 164         cmp.c   r8, r5
 165         bgtu    do_end_words            /* if a1(len)<t0(56) ,unsigned */
 166         andri.c r26, src, 0x4
 167         beq     qword_align
 168         lw      r8, [src]
 169         subi    r5, 0x4
 170         ADDC(sum, r8)
 171         addi    src, 0x4
 172
 173 qword_align:                            /* 8 bytes */
 174         andri.c r26, src, 0x8
 175         beq     oword_align
 176         lw      r8, [src, 0x0]
 177         lw      r9, [src, 0x4]
 178         subi    r5, 0x8                 /* len-=0x8 */
 179         ADDC(sum, r8)
 180         ADDC(sum, r9)
 181         addi    src, 0x8
 182
 183 oword_align:                            /* 16bytes */
 184         andri.c r26, src, 0x10
 185         beq     begin_movement
 186         lw      r10, [src, 0x08]
 187         lw      r11, [src, 0x0c]
 188         lw      r8, [src, 0x00]
 189         lw      r9, [src, 0x04]
 190         ADDC(sum, r10)
 191         ADDC(sum, r11)
 192         ADDC(sum, r8)
 193         ADDC(sum, r9)
 194         subi    r5, 0x10
 195         addi    src, 0x10
 196
 197 begin_movement:
 198         srli.c  r26, r5, 0x7            /* len>=128? */
 199         beq     1f                      /* len<128 */
 200
 201 /* r26 is the result that computed in oword_align */
 202 move_128bytes:
 203         CSUM_BIGCHUNK(src, 0x00, sum)
 204         CSUM_BIGCHUNK(src, 0x20, sum)
 205         CSUM_BIGCHUNK(src, 0x40, sum)
 206         CSUM_BIGCHUNK(src, 0x60, sum)
 207         subi.c  r26, 0x01               /* r26 equals len/128 */
 208         addi    src, 0x80
 209         bne     move_128bytes
 210
 211 1:      /* len<128,we process 64byte here */
 212         andri.c r10, r5, 0x40
 213         beq     1f
 214
 215 move_64bytes:
 216         CSUM_BIGCHUNK(src, 0x00, sum)
 217         CSUM_BIGCHUNK(src, 0x20, sum)
 218         addi    src, 0x40
 219
 220 1:                                      /* len<64 */
 221         andri   r26, r5, 0x1c           /* 0x1c=28 */
 222         andri.c r10, r5, 0x20
 223         beq     do_end_words            /* decided by andri */
 224
 225 move_32bytes:
 226         CSUM_BIGCHUNK(src, 0x00, sum)
 227         andri   r26, r5, 0x1c
 228         addri   src, src, 0x20
 229
 230 do_end_words:                           /* len<32 */
 231         /* r26 was set already in dword_align */
 232         cmpi.c  r26, 0x0
 233         beq     maybe_end_cruft         /* len<28 or len<56 */
 234         srli    r26, r26, 0x2
 235
 236 end_words:
 237         lw      r8, [src]
 238         subi.c  r26, 0x1                /* unit is 4 byte */
 239         ADDC(sum, r8)
 240         addi    src, 0x4
 241         cmpi.c  r26, 0x0
 242         bne     end_words               /* r26!=0 */
 243
 244 maybe_end_cruft:                        /* len<4 */
 245         andri   r10, r5, 0x3
 246
 247 small_memcpy:
 248         mv      r5, r10
 249         j       small_csumcpy
 250
 251 out:
 252         mv      r4, sum
 253         br      r3
 254
 255 END(csum_partial)