Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 | /* * Linux/PA-RISC Project (http://www.parisc-linux.org/) * * Floating-point emulation code * Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ /* * BEGIN_DESC * * File: * @(#) pa/spmath/fcnvff.c $Revision: 1.1 $ * * Purpose: * Single Floating-point to Double Floating-point * Double Floating-point to Single Floating-point * * External Interfaces: * dbl_to_sgl_fcnvff(srcptr,nullptr,dstptr,status) * sgl_to_dbl_fcnvff(srcptr,nullptr,dstptr,status) * * Internal Interfaces: * * Theory: * <<please update with a overview of the operation of this file>> * * END_DESC */ #include "float.h" #include "sgl_float.h" #include "dbl_float.h" #include "cnv_float.h" /* * Single Floating-point to Double Floating-point */ /*ARGSUSED*/ int sgl_to_dbl_fcnvff( sgl_floating_point *srcptr, unsigned int *nullptr, dbl_floating_point *dstptr, unsigned int *status) { register unsigned int src, resultp1, resultp2; register int src_exponent; src = *srcptr; src_exponent = Sgl_exponent(src); Dbl_allp1(resultp1) = Sgl_all(src); /* set sign of result */ /* * Test for NaN or infinity */ if (src_exponent == SGL_INFINITY_EXPONENT) { /* * determine if NaN or infinity */ if (Sgl_iszero_mantissa(src)) { /* * is infinity; want to return double infinity */ Dbl_setinfinity_exponentmantissa(resultp1,resultp2); Dbl_copytoptr(resultp1,resultp2,dstptr); return(NOEXCEPTION); } else { /* * is NaN; signaling or quiet? */ if (Sgl_isone_signaling(src)) { /* trap if INVALIDTRAP enabled */ if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); /* make NaN quiet */ else { Set_invalidflag(); Sgl_set_quiet(src); } } /* * NaN is quiet, return as double NaN */ Dbl_setinfinity_exponent(resultp1); Sgl_to_dbl_mantissa(src,resultp1,resultp2); Dbl_copytoptr(resultp1,resultp2,dstptr); return(NOEXCEPTION); } } /* * Test for zero or denormalized */ if (src_exponent == 0) { /* * determine if zero or denormalized */ if (Sgl_isnotzero_mantissa(src)) { /* * is denormalized; want to normalize */ Sgl_clear_signexponent(src); Sgl_leftshiftby1(src); Sgl_normalize(src,src_exponent); Sgl_to_dbl_exponent(src_exponent,resultp1); Sgl_to_dbl_mantissa(src,resultp1,resultp2); } else { Dbl_setzero_exponentmantissa(resultp1,resultp2); } Dbl_copytoptr(resultp1,resultp2,dstptr); return(NOEXCEPTION); } /* * No special cases, just complete the conversion */ Sgl_to_dbl_exponent(src_exponent, resultp1); Sgl_to_dbl_mantissa(Sgl_mantissa(src), resultp1,resultp2); Dbl_copytoptr(resultp1,resultp2,dstptr); return(NOEXCEPTION); } /* * Double Floating-point to Single Floating-point */ /*ARGSUSED*/ int dbl_to_sgl_fcnvff( dbl_floating_point *srcptr, unsigned int *nullptr, sgl_floating_point *dstptr, unsigned int *status) { register unsigned int srcp1, srcp2, result; register int src_exponent, dest_exponent, dest_mantissa; register boolean inexact = FALSE, guardbit = FALSE, stickybit = FALSE; register boolean lsb_odd = FALSE; boolean is_tiny; Dbl_copyfromptr(srcptr,srcp1,srcp2); src_exponent = Dbl_exponent(srcp1); Sgl_all(result) = Dbl_allp1(srcp1); /* set sign of result */ /* * Test for NaN or infinity */ if (src_exponent == DBL_INFINITY_EXPONENT) { /* * determine if NaN or infinity */ if (Dbl_iszero_mantissa(srcp1,srcp2)) { /* * is infinity; want to return single infinity */ Sgl_setinfinity_exponentmantissa(result); *dstptr = result; return(NOEXCEPTION); } /* * is NaN; signaling or quiet? */ if (Dbl_isone_signaling(srcp1)) { /* trap if INVALIDTRAP enabled */ if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); else { Set_invalidflag(); /* make NaN quiet */ Dbl_set_quiet(srcp1); } } /* * NaN is quiet, return as single NaN */ Sgl_setinfinity_exponent(result); Sgl_set_mantissa(result,Dallp1(srcp1)<<3 | Dallp2(srcp2)>>29); if (Sgl_iszero_mantissa(result)) Sgl_set_quiet(result); *dstptr = result; return(NOEXCEPTION); } /* * Generate result */ Dbl_to_sgl_exponent(src_exponent,dest_exponent); if (dest_exponent > 0) { Dbl_to_sgl_mantissa(srcp1,srcp2,dest_mantissa,inexact,guardbit, stickybit,lsb_odd); } else { if (Dbl_iszero_exponentmantissa(srcp1,srcp2)){ Sgl_setzero_exponentmantissa(result); *dstptr = result; return(NOEXCEPTION); } if (Is_underflowtrap_enabled()) { Dbl_to_sgl_mantissa(srcp1,srcp2,dest_mantissa,inexact, guardbit,stickybit,lsb_odd); } else { /* compute result, determine inexact info, * and set Underflowflag if appropriate */ Dbl_to_sgl_denormalized(srcp1,srcp2,dest_exponent, dest_mantissa,inexact,guardbit,stickybit,lsb_odd, is_tiny); } } /* * Now round result if not exact */ if (inexact) { switch (Rounding_mode()) { case ROUNDPLUS: if (Sgl_iszero_sign(result)) dest_mantissa++; break; case ROUNDMINUS: if (Sgl_isone_sign(result)) dest_mantissa++; break; case ROUNDNEAREST: if (guardbit) { if (stickybit || lsb_odd) dest_mantissa++; } } } Sgl_set_exponentmantissa(result,dest_mantissa); /* * check for mantissa overflow after rounding */ if ((dest_exponent>0 || Is_underflowtrap_enabled()) && Sgl_isone_hidden(result)) dest_exponent++; /* * Test for overflow */ if (dest_exponent >= SGL_INFINITY_EXPONENT) { /* trap if OVERFLOWTRAP enabled */ if (Is_overflowtrap_enabled()) { /* * Check for gross overflow */ if (dest_exponent >= SGL_INFINITY_EXPONENT+SGL_WRAP) return(UNIMPLEMENTEDEXCEPTION); /* * Adjust bias of result */ Sgl_setwrapped_exponent(result,dest_exponent,ovfl); *dstptr = result; if (inexact) if (Is_inexacttrap_enabled()) return(OVERFLOWEXCEPTION|INEXACTEXCEPTION); else Set_inexactflag(); return(OVERFLOWEXCEPTION); } Set_overflowflag(); inexact = TRUE; /* set result to infinity or largest number */ Sgl_setoverflow(result); } /* * Test for underflow */ else if (dest_exponent <= 0) { /* trap if UNDERFLOWTRAP enabled */ if (Is_underflowtrap_enabled()) { /* * Check for gross underflow */ if (dest_exponent <= -(SGL_WRAP)) return(UNIMPLEMENTEDEXCEPTION); /* * Adjust bias of result */ Sgl_setwrapped_exponent(result,dest_exponent,unfl); *dstptr = result; if (inexact) if (Is_inexacttrap_enabled()) return(UNDERFLOWEXCEPTION|INEXACTEXCEPTION); else Set_inexactflag(); return(UNDERFLOWEXCEPTION); } /* * result is denormalized or signed zero */ if (inexact && is_tiny) Set_underflowflag(); } else Sgl_set_exponent(result,dest_exponent); *dstptr = result; /* * Trap if inexact trap is enabled */ if (inexact) if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION); else Set_inexactflag(); return(NOEXCEPTION); } |