kernel/arch/parisc/math-emu/fcnvfxt.c

   1 /*
   2  * Linux/PA-RISC Project (http://www.parisc-linux.org/)
   3  *
   4  * Floating-point emulation code
   5  *  Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org>
   6  *
   7  *    This program is free software; you can redistribute it and/or modify
   8  *    it under the terms of the GNU General Public License as published by
   9  *    the Free Software Foundation; either version 2, or (at your option)
  10  *    any later version.
  11  *
  12  *    This program is distributed in the hope that it will be useful,
  13  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *    GNU General Public License for more details.
  16  *
  17  *    You should have received a copy of the GNU General Public License
  18  *    along with this program; if not, write to the Free Software
  19  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21 /*
  22  * BEGIN_DESC
  23  *
  24  *  File:
  25  *      @(#)    pa/spmath/fcnvfxt.c             $Revision: 1.1 $
  26  *
  27  *  Purpose:
  28  *      Single Floating-point to Single Fixed-point /w truncated result
  29  *      Single Floating-point to Double Fixed-point /w truncated result
  30  *      Double Floating-point to Single Fixed-point /w truncated result
  31  *      Double Floating-point to Double Fixed-point /w truncated result
  32  *
  33  *  External Interfaces:
  34  *      dbl_to_dbl_fcnvfxt(srcptr,nullptr,dstptr,status)
  35  *      dbl_to_sgl_fcnvfxt(srcptr,nullptr,dstptr,status)
  36  *      sgl_to_dbl_fcnvfxt(srcptr,nullptr,dstptr,status)
  37  *      sgl_to_sgl_fcnvfxt(srcptr,nullptr,dstptr,status)
  38  *
  39  *  Internal Interfaces:
  40  *
  41  *  Theory:
  42  *      <<please update with a overview of the operation of this file>>
  43  *
  44  * END_DESC
  45 */
  46
  47
  48 #include "float.h"
  49 #include "sgl_float.h"
  50 #include "dbl_float.h"
  51 #include "cnv_float.h"
  52
  53 /*
  54  *  Convert single floating-point to single fixed-point format
  55  *  with truncated result
  56  */
  57 /*ARGSUSED*/
  58 int
  59 sgl_to_sgl_fcnvfxt(
  60                     sgl_floating_point *srcptr,
  61                     unsigned int *nullptr,
  62                     int *dstptr,
  63                     unsigned int *status)
  64 {
  65         register unsigned int src, temp;
  66         register int src_exponent, result;
  67
  68         src = *srcptr;
  69         src_exponent = Sgl_exponent(src) - SGL_BIAS;
  70
  71         /*
  72          * Test for overflow
  73          */
  74         if (src_exponent > SGL_FX_MAX_EXP) {
  75                 /* check for MININT */
  76                 if ((src_exponent > SGL_FX_MAX_EXP + 1) ||
  77                 Sgl_isnotzero_mantissa(src) || Sgl_iszero_sign(src)) {
  78                         if (Sgl_iszero_sign(src)) result = 0x7fffffff;
  79                         else result = 0x80000000;
  80
  81                         if (Is_invalidtrap_enabled()) {
  82                             return(INVALIDEXCEPTION);
  83                         }
  84                         Set_invalidflag();
  85                         *dstptr = result;
  86                         return(NOEXCEPTION);
  87                 }
  88         }
  89         /*
  90          * Generate result
  91          */
  92         if (src_exponent >= 0) {
  93                 temp = src;
  94                 Sgl_clear_signexponent_set_hidden(temp);
  95                 Int_from_sgl_mantissa(temp,src_exponent);
  96                 if (Sgl_isone_sign(src))  result = -Sgl_all(temp);
  97                 else result = Sgl_all(temp);
  98                 *dstptr = result;
  99
 100                 /* check for inexact */
 101                 if (Sgl_isinexact_to_fix(src,src_exponent)) {
 102                         if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
 103                         else Set_inexactflag();
 104                 }
 105         }
 106         else {
 107                 *dstptr = 0;
 108
 109                 /* check for inexact */
 110                 if (Sgl_isnotzero_exponentmantissa(src)) {
 111                         if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
 112                         else Set_inexactflag();
 113                 }
 114         }
 115         return(NOEXCEPTION);
 116 }
 117
 118 /*
 119  *  Single Floating-point to Double Fixed-point
 120  */
 121 /*ARGSUSED*/
 122 int
 123 sgl_to_dbl_fcnvfxt(
 124                     sgl_floating_point *srcptr,
 125                     unsigned int *nullptr,
 126                     dbl_integer *dstptr,
 127                     unsigned int *status)
 128 {
 129         register int src_exponent, resultp1;
 130         register unsigned int src, temp, resultp2;
 131
 132         src = *srcptr;
 133         src_exponent = Sgl_exponent(src) - SGL_BIAS;
 134
 135         /*
 136          * Test for overflow
 137          */
 138         if (src_exponent > DBL_FX_MAX_EXP) {
 139                 /* check for MININT */
 140                 if ((src_exponent > DBL_FX_MAX_EXP + 1) ||
 141                 Sgl_isnotzero_mantissa(src) || Sgl_iszero_sign(src)) {
 142                         if (Sgl_iszero_sign(src)) {
 143                               resultp1 = 0x7fffffff;
 144                               resultp2 = 0xffffffff;
 145                         }
 146                         else {
 147                             resultp1 = 0x80000000;
 148                             resultp2 = 0;
 149                         }
 150                         if (Is_invalidtrap_enabled()) {
 151                             return(INVALIDEXCEPTION);
 152                         }
 153                         Set_invalidflag();
 154                         Dint_copytoptr(resultp1,resultp2,dstptr);
 155                         return(NOEXCEPTION);
 156                 }
 157                 Dint_set_minint(resultp1,resultp2);
 158                 Dint_copytoptr(resultp1,resultp2,dstptr);
 159                 return(NOEXCEPTION);
 160         }
 161         /*
 162          * Generate result
 163          */
 164         if (src_exponent >= 0) {
 165                 temp = src;
 166                 Sgl_clear_signexponent_set_hidden(temp);
 167                 Dint_from_sgl_mantissa(temp,src_exponent,resultp1,resultp2);
 168                 if (Sgl_isone_sign(src)) {
 169                         Dint_setone_sign(resultp1,resultp2);
 170                 }
 171                 Dint_copytoptr(resultp1,resultp2,dstptr);
 172
 173                 /* check for inexact */
 174                 if (Sgl_isinexact_to_fix(src,src_exponent)) {
 175                         if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
 176                         else Set_inexactflag();
 177                 }
 178         }
 179         else {
 180                 Dint_setzero(resultp1,resultp2);
 181                 Dint_copytoptr(resultp1,resultp2,dstptr);
 182
 183                 /* check for inexact */
 184                 if (Sgl_isnotzero_exponentmantissa(src)) {
 185                         if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
 186                         else Set_inexactflag();
 187                 }
 188         }
 189         return(NOEXCEPTION);
 190 }
 191
 192 /*
 193  *  Double Floating-point to Single Fixed-point
 194  */
 195 /*ARGSUSED*/
 196 int
 197 dbl_to_sgl_fcnvfxt(
 198                         dbl_floating_point *srcptr,
 199                         unsigned int *nullptr,
 200                         int *dstptr,
 201                         unsigned int *status)
 202 {
 203         register unsigned int srcp1, srcp2, tempp1, tempp2;
 204         register int src_exponent, result;
 205
 206         Dbl_copyfromptr(srcptr,srcp1,srcp2);
 207         src_exponent = Dbl_exponent(srcp1) - DBL_BIAS;
 208
 209         /*
 210          * Test for overflow
 211          */
 212         if (src_exponent > SGL_FX_MAX_EXP) {
 213                 /* check for MININT */
 214                 if (Dbl_isoverflow_to_int(src_exponent,srcp1,srcp2)) {
 215                         if (Dbl_iszero_sign(srcp1)) result = 0x7fffffff;
 216                         else result = 0x80000000;
 217
 218                         if (Is_invalidtrap_enabled()) {
 219                             return(INVALIDEXCEPTION);
 220                         }
 221                         Set_invalidflag();
 222                         *dstptr = result;
 223                         return(NOEXCEPTION);
 224                 }
 225         }
 226         /*
 227          * Generate result
 228          */
 229         if (src_exponent >= 0) {
 230                 tempp1 = srcp1;
 231                 tempp2 = srcp2;
 232                 Dbl_clear_signexponent_set_hidden(tempp1);
 233                 Int_from_dbl_mantissa(tempp1,tempp2,src_exponent);
 234                 if (Dbl_isone_sign(srcp1) && (src_exponent <= SGL_FX_MAX_EXP))
 235                         result = -Dbl_allp1(tempp1);
 236                 else result = Dbl_allp1(tempp1);
 237                 *dstptr = result;
 238
 239                 /* check for inexact */
 240                 if (Dbl_isinexact_to_fix(srcp1,srcp2,src_exponent)) {
 241                         if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
 242                         else Set_inexactflag();
 243                 }
 244         }
 245         else {
 246                 *dstptr = 0;
 247
 248                 /* check for inexact */
 249                 if (Dbl_isnotzero_exponentmantissa(srcp1,srcp2)) {
 250                         if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
 251                         else Set_inexactflag();
 252                 }
 253         }
 254         return(NOEXCEPTION);
 255 }
 256
 257 /*
 258  *  Double Floating-point to Double Fixed-point
 259  */
 260 /*ARGSUSED*/
 261 int
 262 dbl_to_dbl_fcnvfxt(
 263                         dbl_floating_point *srcptr,
 264                         unsigned int *nullptr,
 265                         dbl_integer *dstptr,
 266                         unsigned int *status)
 267 {
 268         register int src_exponent, resultp1;
 269         register unsigned int srcp1, srcp2, tempp1, tempp2, resultp2;
 270
 271         Dbl_copyfromptr(srcptr,srcp1,srcp2);
 272         src_exponent = Dbl_exponent(srcp1) - DBL_BIAS;
 273
 274         /*
 275          * Test for overflow
 276          */
 277         if (src_exponent > DBL_FX_MAX_EXP) {
 278                 /* check for MININT */
 279                 if ((src_exponent > DBL_FX_MAX_EXP + 1) ||
 280                 Dbl_isnotzero_mantissa(srcp1,srcp2) || Dbl_iszero_sign(srcp1)) {
 281                         if (Dbl_iszero_sign(srcp1)) {
 282                               resultp1 = 0x7fffffff;
 283                               resultp2 = 0xffffffff;
 284                         }
 285                         else {
 286                             resultp1 = 0x80000000;
 287                             resultp2 = 0;
 288                         }
 289                         if (Is_invalidtrap_enabled()) {
 290                             return(INVALIDEXCEPTION);
 291                         }
 292                         Set_invalidflag();
 293                         Dint_copytoptr(resultp1,resultp2,dstptr);
 294                         return(NOEXCEPTION);
 295                 }
 296         }
 297         /*
 298          * Generate result
 299          */
 300         if (src_exponent >= 0) {
 301                 tempp1 = srcp1;
 302                 tempp2 = srcp2;
 303                 Dbl_clear_signexponent_set_hidden(tempp1);
 304                 Dint_from_dbl_mantissa(tempp1,tempp2,src_exponent,
 305                 resultp1,resultp2);
 306                 if (Dbl_isone_sign(srcp1)) {
 307                         Dint_setone_sign(resultp1,resultp2);
 308                 }
 309                 Dint_copytoptr(resultp1,resultp2,dstptr);
 310
 311                 /* check for inexact */
 312                 if (Dbl_isinexact_to_fix(srcp1,srcp2,src_exponent)) {
 313                         if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
 314                         else Set_inexactflag();
 315                 }
 316         }
 317         else {
 318                 Dint_setzero(resultp1,resultp2);
 319                 Dint_copytoptr(resultp1,resultp2,dstptr);
 320
 321                 /* check for inexact */
 322                 if (Dbl_isnotzero_exponentmantissa(srcp1,srcp2)) {
 323                         if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
 324                         else Set_inexactflag();
 325                 }
 326         }
 327         return(NOEXCEPTION);
 328 }