arch/blackfin/lib/memmove.S

   1 /*
   2  * File:         arch/blackfin/lib/memmove.S
   3  * Based on:
   4  * Author:
   5  *
   6  * Created:
   7  * Description:
   8  *
   9  * Modified:
  10  *               Copyright 2004-2006 Analog Devices Inc.
  11  *
  12  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, see the file COPYING, or write
  26  * to the Free Software Foundation, Inc.,
  27  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  28  */
  29
  30 #include <linux/linkage.h>
  31
  32 .align 2
  33
  34 /*
  35  * C Library function MEMMOVE
  36  * R0 = To Address (leave unchanged to form result)
  37  * R1 = From Address
  38  * R2 = count
  39  * Data may overlap
  40  */
  41
  42 ENTRY(_memmove)
  43         I1 = P3;
  44         P0 = R0;                  /* P0 = To address */
  45         P3 = R1;                  /* P3 = From Address */
  46         P2 = R2;                  /* P2 = count */
  47         CC = P2 == 0;             /* Check zero count*/
  48         IF CC JUMP .Lfinished;    /* very unlikely */
  49
  50         CC = R1 < R0 (IU);        /* From < To */
  51         IF !CC JUMP .Lno_overlap;
  52         R3 = R1 + R2;
  53         CC = R0 <= R3 (IU);       /* (From+len) >= To */
  54         IF CC JUMP .Loverlap;
  55 .Lno_overlap:
  56         R3 = 11;
  57         CC = R2 <= R3;
  58         IF CC JUMP .Lbytes;
  59         R3 = R1 | R0;             /* OR addresses together */
  60         R3 <<= 30;                /* check bottom two bits */
  61         CC =  AZ;                 /* AZ set if zero.*/
  62         IF !CC JUMP .Lbytes;      /* Jump if addrs not aligned.*/
  63
  64         I0 = P3;
  65         P1 = P2 >> 2;             /* count = n/4 */
  66         P1 += -1;
  67         R3 =  3;
  68         R2 = R2 & R3;             /* remainder */
  69         P2 = R2;                  /* set remainder */
  70         R1 = [I0++];
  71
  72         LSETUP (.Lquad_loop, .Lquad_loop) LC0=P1;
  73 .Lquad_loop: MNOP || [P0++] = R1 || R1 = [I0++];
  74         [P0++] = R1;
  75
  76         CC = P2 == 0;             /* any remaining bytes? */
  77         P3 = I0;                  /* Ammend P3 to updated ptr. */
  78         IF !CC JUMP .Lbytes;
  79         P3 = I1;
  80         RTS;
  81
  82 .Lbytes:     LSETUP (.Lbyte2_s, .Lbyte2_e) LC0=P2;
  83 .Lbyte2_s:   R1 = B[P3++](Z);
  84 .Lbyte2_e:   B[P0++] = R1;
  85
  86 .Lfinished:  P3 = I1;
  87         RTS;
  88
  89 .Loverlap:
  90         P2 += -1;
  91         P0 = P0 + P2;
  92         P3 = P3 + P2;
  93         R1 = B[P3--] (Z);
  94         CC = P2 == 0;
  95         IF CC JUMP .Lno_loop;
  96         LSETUP (.Lol_s, .Lol_e) LC0 = P2;
  97 .Lol_s:    B[P0--] = R1;
  98 .Lol_e:    R1 = B[P3--] (Z);
  99 .Lno_loop: B[P0] = R1;
 100         P3 = I1;
 101         RTS;
 102
 103 .size _memmove,.-_memmove