l4/pkg/ocaml/contrib/otherlibs/num/bng_ppc.c

   1 /***********************************************************************/
   2 /*                                                                     */
   3 /*                           Objective Caml                            */
   4 /*                                                                     */
   5 /*            Xavier Leroy, projet Cristal, INRIA Rocquencourt         */
   6 /*                                                                     */
   7 /*  Copyright 2003 Institut National de Recherche en Informatique et   */
   8 /*  en Automatique.  All rights reserved.  This file is distributed    */
   9 /*  under the terms of the GNU Library General Public License, with    */
  10 /*  the special exception on linking described in file ../../LICENSE.  */
  11 /*                                                                     */
  12 /***********************************************************************/
  13
  14 /* $Id: bng_ppc.c 7430 2006-05-31 08:16:34Z xleroy $ */
  15
  16 /* Code specific to the PowerPC architecture. */
  17
  18 #define BngAdd2(res,carryout,arg1,arg2)                                     \
  19   asm("addc %0, %2, %3 \n\t"                                                \
  20       "li %1, 0 \n\t"                                                       \
  21       "addze %1, %1"                                                        \
  22       : "=r" (res), "=r" (carryout)                                         \
  23       : "r" (arg1), "r" (arg2))
  24
  25 #define BngAdd2Carry(res,carryout,arg1,arg2,carryin)                        \
  26   asm("addic %1, %4, -1 \n\t"                                               \
  27       "adde %0, %2, %3 \n\t"                                                \
  28       "li %1, 0 \n\t"                                                       \
  29       "addze %1, %1"                                                        \
  30       : "=r" (res), "=&r" (carryout)                                        \
  31       : "r" (arg1), "r" (arg2), "1" (carryin))
  32
  33 #define BngAdd3(res,carryaccu,arg1,arg2,arg3)                               \
  34   asm("addc %0, %2, %3 \n\t"                                                \
  35       "addze %1, %1 \n\t"                                                   \
  36       "addc %0, %0, %4 \n\t"                                                \
  37       "addze %1, %1"                                                        \
  38       : "=&r" (res), "=&r" (carryaccu)                                      \
  39       : "r" (arg1), "r" (arg2), "r" (arg3), "1" (carryaccu))
  40
  41 /* The "subtract" instructions interpret carry differently than what we
  42    need: the processor carry bit CA is 1 if no carry occured,
  43    0 if a carry occured.  In other terms, CA = !carry.
  44    Thus, subfe rd,ra,rb computes rd = ra - rb - !CA
  45          subfe rd,rd,rd sets rd = - !CA
  46          subfe rd,rd,rd; neg rd, rd sets rd = !CA and recovers "our" carry. */
  47
  48 #define BngSub2(res,carryout,arg1,arg2)                                     \
  49   asm("subfc %0, %3, %2 \n\t"                                               \
  50       "subfe %1, %1, %1\n\t"                                                \
  51       "neg %1, %1"                                                          \
  52       : "=r" (res), "=r" (carryout)                                         \
  53       : "r" (arg1), "r" (arg2))
  54
  55 #define BngSub2Carry(res,carryout,arg1,arg2,carryin)                        \
  56   asm("subfic %1, %4, 0 \n\t"                                               \
  57       "subfe %0, %3, %2 \n\t"                                               \
  58       "subfe %1, %1, %1 \n\t"                                               \
  59       "neg %1, %1"                                                          \
  60       : "=r" (res), "=&r" (carryout)                                        \
  61       : "r" (arg1), "r" (arg2), "1" (carryin))
  62
  63 /* Here is what happens with carryaccu:
  64        neg %1, %1       carryaccu = -carryaccu
  65        addze %1, %1     carryaccu += !carry1
  66        addze %1, %1     carryaccu += !carry2
  67        subifc %1, %1, 2 carryaccu = 2 - carryaccu
  68    Thus, carryaccu_final = carryaccu_initial + 2 - (1 - carry1) - (1 - carry2)
  69                          = carryaccu_initial + carry1 + carry2
  70 */
  71
  72 #define BngSub3(res,carryaccu,arg1,arg2,arg3)                               \
  73   asm("neg %1, %1 \n\t"                                                     \
  74       "subfc %0, %3, %2 \n\t"                                               \
  75       "addze %1, %1 \n\t"                                                   \
  76       "subfc %0, %4, %0 \n\t"                                               \
  77       "addze %1, %1 \n\t"                                                   \
  78       "subfic %1, %1, 2 \n\t"                                               \
  79       : "=&r" (res), "=&r" (carryaccu)                                      \
  80       : "r" (arg1), "r" (arg2), "r" (arg3), "1" (carryaccu))
  81
  82 #ifdef __ppc64__
  83 #define BngMult(resh,resl,arg1,arg2)                                        \
  84   asm("mulld %0, %2, %3 \n\t"                                               \
  85       "mulhdu %1, %2, %3"                                                   \
  86       : "=&r" (resl), "=r" (resh)                                           \
  87       : "r" (arg1), "r" (arg2))
  88 #else
  89 #define BngMult(resh,resl,arg1,arg2)                                        \
  90   asm("mullw %0, %2, %3 \n\t"                                               \
  91       "mulhwu %1, %2, %3"                                                   \
  92       : "=&r" (resl), "=r" (resh)                                           \
  93       : "r" (arg1), "r" (arg2))
  94 #endif