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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 | /* * 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/dfrem.c $Revision: 1.1 $ * * Purpose: * Double Precision Floating-point Remainder * * External Interfaces: * dbl_frem(srcptr1,srcptr2,dstptr,status) * * Internal Interfaces: * * Theory: * <<please update with a overview of the operation of this file>> * * END_DESC */ #include "float.h" #include "dbl_float.h" /* * Double Precision Floating-point Remainder */ int dbl_frem (dbl_floating_point * srcptr1, dbl_floating_point * srcptr2, dbl_floating_point * dstptr, unsigned int *status) { register unsigned int opnd1p1, opnd1p2, opnd2p1, opnd2p2; register unsigned int resultp1, resultp2; register int opnd1_exponent, opnd2_exponent, dest_exponent, stepcount; register boolean roundup = FALSE; Dbl_copyfromptr(srcptr1,opnd1p1,opnd1p2); Dbl_copyfromptr(srcptr2,opnd2p1,opnd2p2); /* * check first operand for NaN's or infinity */ if ((opnd1_exponent = Dbl_exponent(opnd1p1)) == DBL_INFINITY_EXPONENT) { if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) { if (Dbl_isnotnan(opnd2p1,opnd2p2)) { /* invalid since first operand is infinity */ if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); Set_invalidflag(); Dbl_makequietnan(resultp1,resultp2); Dbl_copytoptr(resultp1,resultp2,dstptr); return(NOEXCEPTION); } } else { /* * is NaN; signaling or quiet? */ if (Dbl_isone_signaling(opnd1p1)) { /* trap if INVALIDTRAP enabled */ if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); /* make NaN quiet */ Set_invalidflag(); Dbl_set_quiet(opnd1p1); } /* * is second operand a signaling NaN? */ else if (Dbl_is_signalingnan(opnd2p1)) { /* trap if INVALIDTRAP enabled */ if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); /* make NaN quiet */ Set_invalidflag(); Dbl_set_quiet(opnd2p1); Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); return(NOEXCEPTION); } /* * return quiet NaN */ Dbl_copytoptr(opnd1p1,opnd1p2,dstptr); return(NOEXCEPTION); } } /* * check second operand for NaN's or infinity */ if ((opnd2_exponent = Dbl_exponent(opnd2p1)) == DBL_INFINITY_EXPONENT) { if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) { /* * return first operand */ Dbl_copytoptr(opnd1p1,opnd1p2,dstptr); return(NOEXCEPTION); } /* * is NaN; signaling or quiet? */ if (Dbl_isone_signaling(opnd2p1)) { /* trap if INVALIDTRAP enabled */ if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); /* make NaN quiet */ Set_invalidflag(); Dbl_set_quiet(opnd2p1); } /* * return quiet NaN */ Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); return(NOEXCEPTION); } /* * check second operand for zero */ if (Dbl_iszero_exponentmantissa(opnd2p1,opnd2p2)) { /* invalid since second operand is zero */ if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); Set_invalidflag(); Dbl_makequietnan(resultp1,resultp2); Dbl_copytoptr(resultp1,resultp2,dstptr); return(NOEXCEPTION); } /* * get sign of result */ resultp1 = opnd1p1; /* * check for denormalized operands */ if (opnd1_exponent == 0) { /* check for zero */ if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) { Dbl_copytoptr(opnd1p1,opnd1p2,dstptr); return(NOEXCEPTION); } /* normalize, then continue */ opnd1_exponent = 1; Dbl_normalize(opnd1p1,opnd1p2,opnd1_exponent); } else { Dbl_clear_signexponent_set_hidden(opnd1p1); } if (opnd2_exponent == 0) { /* normalize, then continue */ opnd2_exponent = 1; Dbl_normalize(opnd2p1,opnd2p2,opnd2_exponent); } else { Dbl_clear_signexponent_set_hidden(opnd2p1); } /* find result exponent and divide step loop count */ dest_exponent = opnd2_exponent - 1; stepcount = opnd1_exponent - opnd2_exponent; /* * check for opnd1/opnd2 < 1 */ if (stepcount < 0) { /* * check for opnd1/opnd2 > 1/2 * * In this case n will round to 1, so * r = opnd1 - opnd2 */ if (stepcount == -1 && Dbl_isgreaterthan(opnd1p1,opnd1p2,opnd2p1,opnd2p2)) { /* set sign */ Dbl_allp1(resultp1) = ~Dbl_allp1(resultp1); /* align opnd2 with opnd1 */ Dbl_leftshiftby1(opnd2p1,opnd2p2); Dbl_subtract(opnd2p1,opnd2p2,opnd1p1,opnd1p2, opnd2p1,opnd2p2); /* now normalize */ while (Dbl_iszero_hidden(opnd2p1)) { Dbl_leftshiftby1(opnd2p1,opnd2p2); dest_exponent--; } Dbl_set_exponentmantissa(resultp1,resultp2,opnd2p1,opnd2p2); goto testforunderflow; } /* * opnd1/opnd2 <= 1/2 * * In this case n will round to zero, so * r = opnd1 */ Dbl_set_exponentmantissa(resultp1,resultp2,opnd1p1,opnd1p2); dest_exponent = opnd1_exponent; goto testforunderflow; } /* * Generate result * * Do iterative subtract until remainder is less than operand 2. */ while (stepcount-- > 0 && (Dbl_allp1(opnd1p1) || Dbl_allp2(opnd1p2))) { if (Dbl_isnotlessthan(opnd1p1,opnd1p2,opnd2p1,opnd2p2)) { Dbl_subtract(opnd1p1,opnd1p2,opnd2p1,opnd2p2,opnd1p1,opnd1p2); } Dbl_leftshiftby1(opnd1p1,opnd1p2); } /* * Do last subtract, then determine which way to round if remainder * is exactly 1/2 of opnd2 */ if (Dbl_isnotlessthan(opnd1p1,opnd1p2,opnd2p1,opnd2p2)) { Dbl_subtract(opnd1p1,opnd1p2,opnd2p1,opnd2p2,opnd1p1,opnd1p2); roundup = TRUE; } if (stepcount > 0 || Dbl_iszero(opnd1p1,opnd1p2)) { /* division is exact, remainder is zero */ Dbl_setzero_exponentmantissa(resultp1,resultp2); Dbl_copytoptr(resultp1,resultp2,dstptr); return(NOEXCEPTION); } /* * Check for cases where opnd1/opnd2 < n * * In this case the result's sign will be opposite that of * opnd1. The mantissa also needs some correction. */ Dbl_leftshiftby1(opnd1p1,opnd1p2); if (Dbl_isgreaterthan(opnd1p1,opnd1p2,opnd2p1,opnd2p2)) { Dbl_invert_sign(resultp1); Dbl_leftshiftby1(opnd2p1,opnd2p2); Dbl_subtract(opnd2p1,opnd2p2,opnd1p1,opnd1p2,opnd1p1,opnd1p2); } /* check for remainder being exactly 1/2 of opnd2 */ else if (Dbl_isequal(opnd1p1,opnd1p2,opnd2p1,opnd2p2) && roundup) { Dbl_invert_sign(resultp1); } /* normalize result's mantissa */ while (Dbl_iszero_hidden(opnd1p1)) { dest_exponent--; Dbl_leftshiftby1(opnd1p1,opnd1p2); } Dbl_set_exponentmantissa(resultp1,resultp2,opnd1p1,opnd1p2); /* * Test for underflow */ testforunderflow: if (dest_exponent <= 0) { /* trap if UNDERFLOWTRAP enabled */ if (Is_underflowtrap_enabled()) { /* * Adjust bias of result */ Dbl_setwrapped_exponent(resultp1,dest_exponent,unfl); /* frem is always exact */ Dbl_copytoptr(resultp1,resultp2,dstptr); return(UNDERFLOWEXCEPTION); } /* * denormalize result or set to signed zero */ if (dest_exponent >= (1 - DBL_P)) { Dbl_rightshift_exponentmantissa(resultp1,resultp2, 1-dest_exponent); } else { Dbl_setzero_exponentmantissa(resultp1,resultp2); } } else Dbl_set_exponent(resultp1,dest_exponent); Dbl_copytoptr(resultp1,resultp2,dstptr); return(NOEXCEPTION); } |