arch/blackfin/lib/modsi3.S

   1 /*
   2  * File:         arch/blackfin/lib/modsi3.S
   3  * Based on:
   4  * Author:
   5  *
   6  * Created:
   7  * Description:  This program computes 32 bit signed remainder. It calls div32 function
   8  *               for quotient estimation.
   9  *
  10  *               Registers used :
  11  *               Numerator/ Denominator in  R0, R1
  12  *                 R0  -  returns remainder.
  13  *                 R2-R7
  14  *
  15  * Modified:
  16  *               Copyright 2004-2006 Analog Devices Inc.
  17  *
  18  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
  19  *
  20  * This program is free software; you can redistribute it and/or modify
  21  * it under the terms of the GNU General Public License as published by
  22  * the Free Software Foundation; either version 2 of the License, or
  23  * (at your option) any later version.
  24  *
  25  * This program is distributed in the hope that it will be useful,
  26  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  27  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  28  * GNU General Public License for more details.
  29  *
  30  * You should have received a copy of the GNU General Public License
  31  * along with this program; if not, see the file COPYING, or write
  32  * to the Free Software Foundation, Inc.,
  33  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  34  */
  35
  36 .global ___modsi3;
  37 .type ___modsi3, STT_FUNC;
  38 .extern ___divsi3;
  39 .type ___divsi3, STT_FUNC;
  40
  41 #ifdef CONFIG_ARITHMETIC_OPS_L1
  42 .section .l1.text
  43 #else
  44 .text
  45 #endif
  46
  47 ___modsi3:
  48
  49         CC=R0==0;
  50         IF CC JUMP .LRETURN_R0;         /* Return 0, if numerator  == 0 */
  51         CC=R1==0;
  52         IF CC JUMP .LRETURN_ZERO;               /* Return 0, if denominator == 0 */
  53         CC=R0==R1;
  54         IF CC JUMP .LRETURN_ZERO;               /* Return 0, if numerator == denominator */
  55         CC = R1 == 1;
  56         IF CC JUMP .LRETURN_ZERO;               /* Return 0, if denominator ==  1 */
  57         CC = R1 == -1;
  58         IF CC JUMP .LRETURN_ZERO;               /* Return 0, if denominator == -1 */
  59
  60         /* Valid input. Use __divsi3() to compute the quotient, and then
  61          * derive the remainder from that. */
  62
  63         [--SP] = (R7:6);                /* Push  R7 and R6 */
  64         [--SP] = RETS;                  /* and return address */
  65         R7 = R0;                        /* Copy of R0 */
  66         R6 = R1;                        /* Save for later */
  67         SP += -12;                      /* Should always provide this space */
  68         CALL ___divsi3;                 /* Compute signed quotient using ___divsi3()*/
  69         SP += 12;
  70         R0 *= R6;                       /* Quotient * divisor */
  71         R0 = R7 - R0;                   /* Dividend - (quotient * divisor) */
  72         RETS = [SP++];                  /* Get back return address */
  73         (R7:6) = [SP++];                /* Pop registers R7 and R4 */
  74         RTS;                            /* Store remainder    */
  75
  76 .LRETURN_ZERO:
  77         R0 = 0;
  78 .LRETURN_R0:
  79         RTS;
  80
  81 .size ___modsi3, .-___modsi3