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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 | /* * 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/fcnvxf.c $Revision: 1.1 $ * * Purpose: * Single Fixed-point to Single Floating-point * Single Fixed-point to Double Floating-point * Double Fixed-point to Single Floating-point * Double Fixed-point to Double Floating-point * * External Interfaces: * dbl_to_dbl_fcnvxf(srcptr,nullptr,dstptr,status) * dbl_to_sgl_fcnvxf(srcptr,nullptr,dstptr,status) * sgl_to_dbl_fcnvxf(srcptr,nullptr,dstptr,status) * sgl_to_sgl_fcnvxf(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" /* * Convert single fixed-point to single floating-point format */ int sgl_to_sgl_fcnvxf( int *srcptr, unsigned int *nullptr, sgl_floating_point *dstptr, unsigned int *status) { register int src, dst_exponent; register unsigned int result = 0; src = *srcptr; /* * set sign bit of result and get magnitude of source */ if (src < 0) { Sgl_setone_sign(result); Int_negate(src); } else { Sgl_setzero_sign(result); /* Check for zero */ if (src == 0) { Sgl_setzero(result); *dstptr = result; return(NOEXCEPTION); } } /* * Generate exponent and normalized mantissa */ dst_exponent = 16; /* initialize for normalization */ /* * Check word for most significant bit set. Returns * a value in dst_exponent indicating the bit position, * between -1 and 30. */ Find_ms_one_bit(src,dst_exponent); /* left justify source, with msb at bit position 1 */ if (dst_exponent >= 0) src <<= dst_exponent; else src = 1 << 30; Sgl_set_mantissa(result, src >> (SGL_EXP_LENGTH-1)); Sgl_set_exponent(result, 30+SGL_BIAS - dst_exponent); /* check for inexact */ if (Int_isinexact_to_sgl(src)) { switch (Rounding_mode()) { case ROUNDPLUS: if (Sgl_iszero_sign(result)) Sgl_increment(result); break; case ROUNDMINUS: if (Sgl_isone_sign(result)) Sgl_increment(result); break; case ROUNDNEAREST: Sgl_roundnearest_from_int(src,result); } if (Is_inexacttrap_enabled()) { *dstptr = result; return(INEXACTEXCEPTION); } else Set_inexactflag(); } *dstptr = result; return(NOEXCEPTION); } /* * Single Fixed-point to Double Floating-point */ int sgl_to_dbl_fcnvxf( int *srcptr, unsigned int *nullptr, dbl_floating_point *dstptr, unsigned int *status) { register int src, dst_exponent; register unsigned int resultp1 = 0, resultp2 = 0; src = *srcptr; /* * set sign bit of result and get magnitude of source */ if (src < 0) { Dbl_setone_sign(resultp1); Int_negate(src); } else { Dbl_setzero_sign(resultp1); /* Check for zero */ if (src == 0) { Dbl_setzero(resultp1,resultp2); Dbl_copytoptr(resultp1,resultp2,dstptr); return(NOEXCEPTION); } } /* * Generate exponent and normalized mantissa */ dst_exponent = 16; /* initialize for normalization */ /* * Check word for most significant bit set. Returns * a value in dst_exponent indicating the bit position, * between -1 and 30. */ Find_ms_one_bit(src,dst_exponent); /* left justify source, with msb at bit position 1 */ if (dst_exponent >= 0) src <<= dst_exponent; else src = 1 << 30; Dbl_set_mantissap1(resultp1, src >> DBL_EXP_LENGTH - 1); Dbl_set_mantissap2(resultp2, src << (33-DBL_EXP_LENGTH)); Dbl_set_exponent(resultp1, (30+DBL_BIAS) - dst_exponent); Dbl_copytoptr(resultp1,resultp2,dstptr); return(NOEXCEPTION); } /* * Double Fixed-point to Single Floating-point */ int dbl_to_sgl_fcnvxf( dbl_integer *srcptr, unsigned int *nullptr, sgl_floating_point *dstptr, unsigned int *status) { int dst_exponent, srcp1; unsigned int result = 0, srcp2; Dint_copyfromptr(srcptr,srcp1,srcp2); /* * set sign bit of result and get magnitude of source */ if (srcp1 < 0) { Sgl_setone_sign(result); Dint_negate(srcp1,srcp2); } else { Sgl_setzero_sign(result); /* Check for zero */ if (srcp1 == 0 && srcp2 == 0) { Sgl_setzero(result); *dstptr = result; return(NOEXCEPTION); } } /* * Generate exponent and normalized mantissa */ dst_exponent = 16; /* initialize for normalization */ if (srcp1 == 0) { /* * Check word for most significant bit set. Returns * a value in dst_exponent indicating the bit position, * between -1 and 30. */ Find_ms_one_bit(srcp2,dst_exponent); /* left justify source, with msb at bit position 1 */ if (dst_exponent >= 0) { srcp1 = srcp2 << dst_exponent; srcp2 = 0; } else { srcp1 = srcp2 >> 1; srcp2 <<= 31; } /* * since msb set is in second word, need to * adjust bit position count */ dst_exponent += 32; } else { /* * Check word for most significant bit set. Returns * a value in dst_exponent indicating the bit position, * between -1 and 30. * */ Find_ms_one_bit(srcp1,dst_exponent); /* left justify source, with msb at bit position 1 */ if (dst_exponent > 0) { Variable_shift_double(srcp1,srcp2,(32-dst_exponent), srcp1); srcp2 <<= dst_exponent; } /* * If dst_exponent = 0, we don't need to shift anything. * If dst_exponent = -1, src = - 2**63 so we won't need to * shift srcp2. */ else srcp1 >>= -(dst_exponent); } Sgl_set_mantissa(result, srcp1 >> SGL_EXP_LENGTH - 1); Sgl_set_exponent(result, (62+SGL_BIAS) - dst_exponent); /* check for inexact */ if (Dint_isinexact_to_sgl(srcp1,srcp2)) { switch (Rounding_mode()) { case ROUNDPLUS: if (Sgl_iszero_sign(result)) Sgl_increment(result); break; case ROUNDMINUS: if (Sgl_isone_sign(result)) Sgl_increment(result); break; case ROUNDNEAREST: Sgl_roundnearest_from_dint(srcp1,srcp2,result); } if (Is_inexacttrap_enabled()) { *dstptr = result; return(INEXACTEXCEPTION); } else Set_inexactflag(); } *dstptr = result; return(NOEXCEPTION); } /* * Double Fixed-point to Double Floating-point */ int dbl_to_dbl_fcnvxf( dbl_integer *srcptr, unsigned int *nullptr, dbl_floating_point *dstptr, unsigned int *status) { register int srcp1, dst_exponent; register unsigned int srcp2, resultp1 = 0, resultp2 = 0; Dint_copyfromptr(srcptr,srcp1,srcp2); /* * set sign bit of result and get magnitude of source */ if (srcp1 < 0) { Dbl_setone_sign(resultp1); Dint_negate(srcp1,srcp2); } else { Dbl_setzero_sign(resultp1); /* Check for zero */ if (srcp1 == 0 && srcp2 ==0) { Dbl_setzero(resultp1,resultp2); Dbl_copytoptr(resultp1,resultp2,dstptr); return(NOEXCEPTION); } } /* * Generate exponent and normalized mantissa */ dst_exponent = 16; /* initialize for normalization */ if (srcp1 == 0) { /* * Check word for most significant bit set. Returns * a value in dst_exponent indicating the bit position, * between -1 and 30. */ Find_ms_one_bit(srcp2,dst_exponent); /* left justify source, with msb at bit position 1 */ if (dst_exponent >= 0) { srcp1 = srcp2 << dst_exponent; srcp2 = 0; } else { srcp1 = srcp2 >> 1; srcp2 <<= 31; } /* * since msb set is in second word, need to * adjust bit position count */ dst_exponent += 32; } else { /* * Check word for most significant bit set. Returns * a value in dst_exponent indicating the bit position, * between -1 and 30. */ Find_ms_one_bit(srcp1,dst_exponent); /* left justify source, with msb at bit position 1 */ if (dst_exponent > 0) { Variable_shift_double(srcp1,srcp2,(32-dst_exponent), srcp1); srcp2 <<= dst_exponent; } /* * If dst_exponent = 0, we don't need to shift anything. * If dst_exponent = -1, src = - 2**63 so we won't need to * shift srcp2. */ else srcp1 >>= -(dst_exponent); } Dbl_set_mantissap1(resultp1, srcp1 >> (DBL_EXP_LENGTH-1)); Shiftdouble(srcp1,srcp2,DBL_EXP_LENGTH-1,resultp2); Dbl_set_exponent(resultp1, (62+DBL_BIAS) - dst_exponent); /* check for inexact */ if (Dint_isinexact_to_dbl(srcp2)) { switch (Rounding_mode()) { case ROUNDPLUS: if (Dbl_iszero_sign(resultp1)) { Dbl_increment(resultp1,resultp2); } break; case ROUNDMINUS: if (Dbl_isone_sign(resultp1)) { Dbl_increment(resultp1,resultp2); } break; case ROUNDNEAREST: Dbl_roundnearest_from_dint(srcp2,resultp1, resultp2); } if (Is_inexacttrap_enabled()) { Dbl_copytoptr(resultp1,resultp2,dstptr); return(INEXACTEXCEPTION); } else Set_inexactflag(); } Dbl_copytoptr(resultp1,resultp2,dstptr); return(NOEXCEPTION); } |