dfmpy.c revision 1.1.2.2
1 1.1.2.2 jdolecek /* $NetBSD: dfmpy.c,v 1.1.2.2 2002/06/23 17:37:12 jdolecek Exp $ */ 2 1.1.2.2 jdolecek 3 1.1.2.2 jdolecek /* $OpenBSD: dfmpy.c,v 1.4 2001/03/29 03:58:17 mickey Exp $ */ 4 1.1.2.2 jdolecek 5 1.1.2.2 jdolecek /* 6 1.1.2.2 jdolecek * Copyright 1996 1995 by Open Software Foundation, Inc. 7 1.1.2.2 jdolecek * All Rights Reserved 8 1.1.2.2 jdolecek * 9 1.1.2.2 jdolecek * Permission to use, copy, modify, and distribute this software and 10 1.1.2.2 jdolecek * its documentation for any purpose and without fee is hereby granted, 11 1.1.2.2 jdolecek * provided that the above copyright notice appears in all copies and 12 1.1.2.2 jdolecek * that both the copyright notice and this permission notice appear in 13 1.1.2.2 jdolecek * supporting documentation. 14 1.1.2.2 jdolecek * 15 1.1.2.2 jdolecek * OSF DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE 16 1.1.2.2 jdolecek * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 17 1.1.2.2 jdolecek * FOR A PARTICULAR PURPOSE. 18 1.1.2.2 jdolecek * 19 1.1.2.2 jdolecek * IN NO EVENT SHALL OSF BE LIABLE FOR ANY SPECIAL, INDIRECT, OR 20 1.1.2.2 jdolecek * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 21 1.1.2.2 jdolecek * LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT, 22 1.1.2.2 jdolecek * NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION 23 1.1.2.2 jdolecek * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 24 1.1.2.2 jdolecek * 25 1.1.2.2 jdolecek */ 26 1.1.2.2 jdolecek /* 27 1.1.2.2 jdolecek * pmk1.1 28 1.1.2.2 jdolecek */ 29 1.1.2.2 jdolecek /* 30 1.1.2.2 jdolecek * (c) Copyright 1986 HEWLETT-PACKARD COMPANY 31 1.1.2.2 jdolecek * 32 1.1.2.2 jdolecek * To anyone who acknowledges that this file is provided "AS IS" 33 1.1.2.2 jdolecek * without any express or implied warranty: 34 1.1.2.2 jdolecek * permission to use, copy, modify, and distribute this file 35 1.1.2.2 jdolecek * for any purpose is hereby granted without fee, provided that 36 1.1.2.2 jdolecek * the above copyright notice and this notice appears in all 37 1.1.2.2 jdolecek * copies, and that the name of Hewlett-Packard Company not be 38 1.1.2.2 jdolecek * used in advertising or publicity pertaining to distribution 39 1.1.2.2 jdolecek * of the software without specific, written prior permission. 40 1.1.2.2 jdolecek * Hewlett-Packard Company makes no representations about the 41 1.1.2.2 jdolecek * suitability of this software for any purpose. 42 1.1.2.2 jdolecek */ 43 1.1.2.2 jdolecek 44 1.1.2.2 jdolecek #include "../spmath/float.h" 45 1.1.2.2 jdolecek #include "../spmath/dbl_float.h" 46 1.1.2.2 jdolecek 47 1.1.2.2 jdolecek /* 48 1.1.2.2 jdolecek * Double Precision Floating-point Multiply 49 1.1.2.2 jdolecek */ 50 1.1.2.2 jdolecek 51 1.1.2.2 jdolecek int 52 1.1.2.2 jdolecek dbl_fmpy(srcptr1,srcptr2,dstptr,status) 53 1.1.2.2 jdolecek 54 1.1.2.2 jdolecek dbl_floating_point *srcptr1, *srcptr2, *dstptr; 55 1.1.2.2 jdolecek unsigned int *status; 56 1.1.2.2 jdolecek { 57 1.1.2.2 jdolecek register unsigned int opnd1p1, opnd1p2, opnd2p1, opnd2p2; 58 1.1.2.2 jdolecek register unsigned int opnd3p1, opnd3p2, resultp1, resultp2; 59 1.1.2.2 jdolecek register int dest_exponent, count; 60 1.1.2.2 jdolecek register int inexact = FALSE, guardbit = FALSE, stickybit = FALSE; 61 1.1.2.2 jdolecek int is_tiny; 62 1.1.2.2 jdolecek 63 1.1.2.2 jdolecek Dbl_copyfromptr(srcptr1,opnd1p1,opnd1p2); 64 1.1.2.2 jdolecek Dbl_copyfromptr(srcptr2,opnd2p1,opnd2p2); 65 1.1.2.2 jdolecek 66 1.1.2.2 jdolecek /* 67 1.1.2.2 jdolecek * set sign bit of result 68 1.1.2.2 jdolecek */ 69 1.1.2.2 jdolecek if (Dbl_sign(opnd1p1) ^ Dbl_sign(opnd2p1)) 70 1.1.2.2 jdolecek Dbl_setnegativezerop1(resultp1); 71 1.1.2.2 jdolecek else Dbl_setzerop1(resultp1); 72 1.1.2.2 jdolecek /* 73 1.1.2.2 jdolecek * check first operand for NaN's or infinity 74 1.1.2.2 jdolecek */ 75 1.1.2.2 jdolecek if (Dbl_isinfinity_exponent(opnd1p1)) { 76 1.1.2.2 jdolecek if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) { 77 1.1.2.2 jdolecek if (Dbl_isnotnan(opnd2p1,opnd2p2)) { 78 1.1.2.2 jdolecek if (Dbl_iszero_exponentmantissa(opnd2p1,opnd2p2)) { 79 1.1.2.2 jdolecek /* 80 1.1.2.2 jdolecek * invalid since operands are infinity 81 1.1.2.2 jdolecek * and zero 82 1.1.2.2 jdolecek */ 83 1.1.2.2 jdolecek if (Is_invalidtrap_enabled()) 84 1.1.2.2 jdolecek return(INVALIDEXCEPTION); 85 1.1.2.2 jdolecek Set_invalidflag(); 86 1.1.2.2 jdolecek Dbl_makequietnan(resultp1,resultp2); 87 1.1.2.2 jdolecek Dbl_copytoptr(resultp1,resultp2,dstptr); 88 1.1.2.2 jdolecek return(NOEXCEPTION); 89 1.1.2.2 jdolecek } 90 1.1.2.2 jdolecek /* 91 1.1.2.2 jdolecek * return infinity 92 1.1.2.2 jdolecek */ 93 1.1.2.2 jdolecek Dbl_setinfinity_exponentmantissa(resultp1,resultp2); 94 1.1.2.2 jdolecek Dbl_copytoptr(resultp1,resultp2,dstptr); 95 1.1.2.2 jdolecek return(NOEXCEPTION); 96 1.1.2.2 jdolecek } 97 1.1.2.2 jdolecek } 98 1.1.2.2 jdolecek else { 99 1.1.2.2 jdolecek /* 100 1.1.2.2 jdolecek * is NaN; signaling or quiet? 101 1.1.2.2 jdolecek */ 102 1.1.2.2 jdolecek if (Dbl_isone_signaling(opnd1p1)) { 103 1.1.2.2 jdolecek /* trap if INVALIDTRAP enabled */ 104 1.1.2.2 jdolecek if (Is_invalidtrap_enabled()) 105 1.1.2.2 jdolecek return(INVALIDEXCEPTION); 106 1.1.2.2 jdolecek /* make NaN quiet */ 107 1.1.2.2 jdolecek Set_invalidflag(); 108 1.1.2.2 jdolecek Dbl_set_quiet(opnd1p1); 109 1.1.2.2 jdolecek } 110 1.1.2.2 jdolecek /* 111 1.1.2.2 jdolecek * is second operand a signaling NaN? 112 1.1.2.2 jdolecek */ 113 1.1.2.2 jdolecek else if (Dbl_is_signalingnan(opnd2p1)) { 114 1.1.2.2 jdolecek /* trap if INVALIDTRAP enabled */ 115 1.1.2.2 jdolecek if (Is_invalidtrap_enabled()) 116 1.1.2.2 jdolecek return(INVALIDEXCEPTION); 117 1.1.2.2 jdolecek /* make NaN quiet */ 118 1.1.2.2 jdolecek Set_invalidflag(); 119 1.1.2.2 jdolecek Dbl_set_quiet(opnd2p1); 120 1.1.2.2 jdolecek Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); 121 1.1.2.2 jdolecek return(NOEXCEPTION); 122 1.1.2.2 jdolecek } 123 1.1.2.2 jdolecek /* 124 1.1.2.2 jdolecek * return quiet NaN 125 1.1.2.2 jdolecek */ 126 1.1.2.2 jdolecek Dbl_copytoptr(opnd1p1,opnd1p2,dstptr); 127 1.1.2.2 jdolecek return(NOEXCEPTION); 128 1.1.2.2 jdolecek } 129 1.1.2.2 jdolecek } 130 1.1.2.2 jdolecek /* 131 1.1.2.2 jdolecek * check second operand for NaN's or infinity 132 1.1.2.2 jdolecek */ 133 1.1.2.2 jdolecek if (Dbl_isinfinity_exponent(opnd2p1)) { 134 1.1.2.2 jdolecek if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) { 135 1.1.2.2 jdolecek if (Dbl_iszero_exponentmantissa(opnd1p1,opnd1p2)) { 136 1.1.2.2 jdolecek /* invalid since operands are zero & infinity */ 137 1.1.2.2 jdolecek if (Is_invalidtrap_enabled()) 138 1.1.2.2 jdolecek return(INVALIDEXCEPTION); 139 1.1.2.2 jdolecek Set_invalidflag(); 140 1.1.2.2 jdolecek Dbl_makequietnan(opnd2p1,opnd2p2); 141 1.1.2.2 jdolecek Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); 142 1.1.2.2 jdolecek return(NOEXCEPTION); 143 1.1.2.2 jdolecek } 144 1.1.2.2 jdolecek /* 145 1.1.2.2 jdolecek * return infinity 146 1.1.2.2 jdolecek */ 147 1.1.2.2 jdolecek Dbl_setinfinity_exponentmantissa(resultp1,resultp2); 148 1.1.2.2 jdolecek Dbl_copytoptr(resultp1,resultp2,dstptr); 149 1.1.2.2 jdolecek return(NOEXCEPTION); 150 1.1.2.2 jdolecek } 151 1.1.2.2 jdolecek /* 152 1.1.2.2 jdolecek * is NaN; signaling or quiet? 153 1.1.2.2 jdolecek */ 154 1.1.2.2 jdolecek if (Dbl_isone_signaling(opnd2p1)) { 155 1.1.2.2 jdolecek /* trap if INVALIDTRAP enabled */ 156 1.1.2.2 jdolecek if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); 157 1.1.2.2 jdolecek /* make NaN quiet */ 158 1.1.2.2 jdolecek Set_invalidflag(); 159 1.1.2.2 jdolecek Dbl_set_quiet(opnd2p1); 160 1.1.2.2 jdolecek } 161 1.1.2.2 jdolecek /* 162 1.1.2.2 jdolecek * return quiet NaN 163 1.1.2.2 jdolecek */ 164 1.1.2.2 jdolecek Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); 165 1.1.2.2 jdolecek return(NOEXCEPTION); 166 1.1.2.2 jdolecek } 167 1.1.2.2 jdolecek /* 168 1.1.2.2 jdolecek * Generate exponent 169 1.1.2.2 jdolecek */ 170 1.1.2.2 jdolecek dest_exponent = Dbl_exponent(opnd1p1) + Dbl_exponent(opnd2p1) -DBL_BIAS; 171 1.1.2.2 jdolecek 172 1.1.2.2 jdolecek /* 173 1.1.2.2 jdolecek * Generate mantissa 174 1.1.2.2 jdolecek */ 175 1.1.2.2 jdolecek if (Dbl_isnotzero_exponent(opnd1p1)) { 176 1.1.2.2 jdolecek /* set hidden bit */ 177 1.1.2.2 jdolecek Dbl_clear_signexponent_set_hidden(opnd1p1); 178 1.1.2.2 jdolecek } 179 1.1.2.2 jdolecek else { 180 1.1.2.2 jdolecek /* check for zero */ 181 1.1.2.2 jdolecek if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) { 182 1.1.2.2 jdolecek Dbl_setzero_exponentmantissa(resultp1,resultp2); 183 1.1.2.2 jdolecek Dbl_copytoptr(resultp1,resultp2,dstptr); 184 1.1.2.2 jdolecek return(NOEXCEPTION); 185 1.1.2.2 jdolecek } 186 1.1.2.2 jdolecek /* is denormalized, adjust exponent */ 187 1.1.2.2 jdolecek Dbl_clear_signexponent(opnd1p1); 188 1.1.2.2 jdolecek Dbl_leftshiftby1(opnd1p1,opnd1p2); 189 1.1.2.2 jdolecek Dbl_normalize(opnd1p1,opnd1p2,dest_exponent); 190 1.1.2.2 jdolecek } 191 1.1.2.2 jdolecek /* opnd2 needs to have hidden bit set with msb in hidden bit */ 192 1.1.2.2 jdolecek if (Dbl_isnotzero_exponent(opnd2p1)) { 193 1.1.2.2 jdolecek Dbl_clear_signexponent_set_hidden(opnd2p1); 194 1.1.2.2 jdolecek } 195 1.1.2.2 jdolecek else { 196 1.1.2.2 jdolecek /* check for zero */ 197 1.1.2.2 jdolecek if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) { 198 1.1.2.2 jdolecek Dbl_setzero_exponentmantissa(resultp1,resultp2); 199 1.1.2.2 jdolecek Dbl_copytoptr(resultp1,resultp2,dstptr); 200 1.1.2.2 jdolecek return(NOEXCEPTION); 201 1.1.2.2 jdolecek } 202 1.1.2.2 jdolecek /* is denormalized; want to normalize */ 203 1.1.2.2 jdolecek Dbl_clear_signexponent(opnd2p1); 204 1.1.2.2 jdolecek Dbl_leftshiftby1(opnd2p1,opnd2p2); 205 1.1.2.2 jdolecek Dbl_normalize(opnd2p1,opnd2p2,dest_exponent); 206 1.1.2.2 jdolecek } 207 1.1.2.2 jdolecek 208 1.1.2.2 jdolecek /* Multiply two source mantissas together */ 209 1.1.2.2 jdolecek 210 1.1.2.2 jdolecek /* make room for guard bits */ 211 1.1.2.2 jdolecek Dbl_leftshiftby7(opnd2p1,opnd2p2); 212 1.1.2.2 jdolecek Dbl_setzero(opnd3p1,opnd3p2); 213 1.1.2.2 jdolecek /* 214 1.1.2.2 jdolecek * Four bits at a time are inspected in each loop, and a 215 1.1.2.2 jdolecek * simple shift and add multiply algorithm is used. 216 1.1.2.2 jdolecek */ 217 1.1.2.2 jdolecek for (count=1;count<=DBL_P;count+=4) { 218 1.1.2.2 jdolecek stickybit |= Dlow4p2(opnd3p2); 219 1.1.2.2 jdolecek Dbl_rightshiftby4(opnd3p1,opnd3p2); 220 1.1.2.2 jdolecek if (Dbit28p2(opnd1p2)) { 221 1.1.2.2 jdolecek /* Twoword_add should be an ADDC followed by an ADD. */ 222 1.1.2.2 jdolecek Twoword_add(opnd3p1, opnd3p2, opnd2p1<<3 | opnd2p2>>29, 223 1.1.2.2 jdolecek opnd2p2<<3); 224 1.1.2.2 jdolecek } 225 1.1.2.2 jdolecek if (Dbit29p2(opnd1p2)) { 226 1.1.2.2 jdolecek Twoword_add(opnd3p1, opnd3p2, opnd2p1<<2 | opnd2p2>>30, 227 1.1.2.2 jdolecek opnd2p2<<2); 228 1.1.2.2 jdolecek } 229 1.1.2.2 jdolecek if (Dbit30p2(opnd1p2)) { 230 1.1.2.2 jdolecek Twoword_add(opnd3p1, opnd3p2, opnd2p1<<1 | opnd2p2>>31, 231 1.1.2.2 jdolecek opnd2p2<<1); 232 1.1.2.2 jdolecek } 233 1.1.2.2 jdolecek if (Dbit31p2(opnd1p2)) { 234 1.1.2.2 jdolecek Twoword_add(opnd3p1, opnd3p2, opnd2p1, opnd2p2); 235 1.1.2.2 jdolecek } 236 1.1.2.2 jdolecek Dbl_rightshiftby4(opnd1p1,opnd1p2); 237 1.1.2.2 jdolecek } 238 1.1.2.2 jdolecek if (Dbit3p1(opnd3p1)==0) { 239 1.1.2.2 jdolecek Dbl_leftshiftby1(opnd3p1,opnd3p2); 240 1.1.2.2 jdolecek } 241 1.1.2.2 jdolecek else { 242 1.1.2.2 jdolecek /* result mantissa >= 2. */ 243 1.1.2.2 jdolecek dest_exponent++; 244 1.1.2.2 jdolecek } 245 1.1.2.2 jdolecek /* check for denormalized result */ 246 1.1.2.2 jdolecek while (Dbit3p1(opnd3p1)==0) { 247 1.1.2.2 jdolecek Dbl_leftshiftby1(opnd3p1,opnd3p2); 248 1.1.2.2 jdolecek dest_exponent--; 249 1.1.2.2 jdolecek } 250 1.1.2.2 jdolecek /* 251 1.1.2.2 jdolecek * check for guard, sticky and inexact bits 252 1.1.2.2 jdolecek */ 253 1.1.2.2 jdolecek stickybit |= Dallp2(opnd3p2) << 25; 254 1.1.2.2 jdolecek guardbit = (Dallp2(opnd3p2) << 24) >> 31; 255 1.1.2.2 jdolecek inexact = guardbit | stickybit; 256 1.1.2.2 jdolecek 257 1.1.2.2 jdolecek /* align result mantissa */ 258 1.1.2.2 jdolecek Dbl_rightshiftby8(opnd3p1,opnd3p2); 259 1.1.2.2 jdolecek 260 1.1.2.2 jdolecek /* 261 1.1.2.2 jdolecek * round result 262 1.1.2.2 jdolecek */ 263 1.1.2.2 jdolecek if (inexact && (dest_exponent>0 || Is_underflowtrap_enabled())) { 264 1.1.2.2 jdolecek Dbl_clear_signexponent(opnd3p1); 265 1.1.2.2 jdolecek switch (Rounding_mode()) { 266 1.1.2.2 jdolecek case ROUNDPLUS: 267 1.1.2.2 jdolecek if (Dbl_iszero_sign(resultp1)) 268 1.1.2.2 jdolecek Dbl_increment(opnd3p1,opnd3p2); 269 1.1.2.2 jdolecek break; 270 1.1.2.2 jdolecek case ROUNDMINUS: 271 1.1.2.2 jdolecek if (Dbl_isone_sign(resultp1)) 272 1.1.2.2 jdolecek Dbl_increment(opnd3p1,opnd3p2); 273 1.1.2.2 jdolecek break; 274 1.1.2.2 jdolecek case ROUNDNEAREST: 275 1.1.2.2 jdolecek if (guardbit && 276 1.1.2.2 jdolecek (stickybit || Dbl_isone_lowmantissap2(opnd3p2))) 277 1.1.2.2 jdolecek Dbl_increment(opnd3p1,opnd3p2); 278 1.1.2.2 jdolecek break; 279 1.1.2.2 jdolecek } 280 1.1.2.2 jdolecek if (Dbl_isone_hidden(opnd3p1)) dest_exponent++; 281 1.1.2.2 jdolecek } 282 1.1.2.2 jdolecek Dbl_set_mantissa(resultp1,resultp2,opnd3p1,opnd3p2); 283 1.1.2.2 jdolecek 284 1.1.2.2 jdolecek /* 285 1.1.2.2 jdolecek * Test for overflow 286 1.1.2.2 jdolecek */ 287 1.1.2.2 jdolecek if (dest_exponent >= DBL_INFINITY_EXPONENT) { 288 1.1.2.2 jdolecek /* trap if OVERFLOWTRAP enabled */ 289 1.1.2.2 jdolecek if (Is_overflowtrap_enabled()) { 290 1.1.2.2 jdolecek /* 291 1.1.2.2 jdolecek * Adjust bias of result 292 1.1.2.2 jdolecek */ 293 1.1.2.2 jdolecek Dbl_setwrapped_exponent(resultp1,dest_exponent,ovfl); 294 1.1.2.2 jdolecek Dbl_copytoptr(resultp1,resultp2,dstptr); 295 1.1.2.2 jdolecek if (inexact) { 296 1.1.2.2 jdolecek if (Is_inexacttrap_enabled()) 297 1.1.2.2 jdolecek return (OVERFLOWEXCEPTION | INEXACTEXCEPTION); 298 1.1.2.2 jdolecek else 299 1.1.2.2 jdolecek Set_inexactflag(); 300 1.1.2.2 jdolecek } 301 1.1.2.2 jdolecek return (OVERFLOWEXCEPTION); 302 1.1.2.2 jdolecek } 303 1.1.2.2 jdolecek inexact = TRUE; 304 1.1.2.2 jdolecek Set_overflowflag(); 305 1.1.2.2 jdolecek /* set result to infinity or largest number */ 306 1.1.2.2 jdolecek Dbl_setoverflow(resultp1,resultp2); 307 1.1.2.2 jdolecek } 308 1.1.2.2 jdolecek /* 309 1.1.2.2 jdolecek * Test for underflow 310 1.1.2.2 jdolecek */ 311 1.1.2.2 jdolecek else if (dest_exponent <= 0) { 312 1.1.2.2 jdolecek /* trap if UNDERFLOWTRAP enabled */ 313 1.1.2.2 jdolecek if (Is_underflowtrap_enabled()) { 314 1.1.2.2 jdolecek /* 315 1.1.2.2 jdolecek * Adjust bias of result 316 1.1.2.2 jdolecek */ 317 1.1.2.2 jdolecek Dbl_setwrapped_exponent(resultp1,dest_exponent,unfl); 318 1.1.2.2 jdolecek Dbl_copytoptr(resultp1,resultp2,dstptr); 319 1.1.2.2 jdolecek if (inexact) { 320 1.1.2.2 jdolecek if (Is_inexacttrap_enabled()) 321 1.1.2.2 jdolecek return (UNDERFLOWEXCEPTION | INEXACTEXCEPTION); 322 1.1.2.2 jdolecek else 323 1.1.2.2 jdolecek Set_inexactflag(); 324 1.1.2.2 jdolecek } 325 1.1.2.2 jdolecek return (UNDERFLOWEXCEPTION); 326 1.1.2.2 jdolecek } 327 1.1.2.2 jdolecek 328 1.1.2.2 jdolecek /* Determine if should set underflow flag */ 329 1.1.2.2 jdolecek is_tiny = TRUE; 330 1.1.2.2 jdolecek if (dest_exponent == 0 && inexact) { 331 1.1.2.2 jdolecek switch (Rounding_mode()) { 332 1.1.2.2 jdolecek case ROUNDPLUS: 333 1.1.2.2 jdolecek if (Dbl_iszero_sign(resultp1)) { 334 1.1.2.2 jdolecek Dbl_increment(opnd3p1,opnd3p2); 335 1.1.2.2 jdolecek if (Dbl_isone_hiddenoverflow(opnd3p1)) 336 1.1.2.2 jdolecek is_tiny = FALSE; 337 1.1.2.2 jdolecek Dbl_decrement(opnd3p1,opnd3p2); 338 1.1.2.2 jdolecek } 339 1.1.2.2 jdolecek break; 340 1.1.2.2 jdolecek case ROUNDMINUS: 341 1.1.2.2 jdolecek if (Dbl_isone_sign(resultp1)) { 342 1.1.2.2 jdolecek Dbl_increment(opnd3p1,opnd3p2); 343 1.1.2.2 jdolecek if (Dbl_isone_hiddenoverflow(opnd3p1)) 344 1.1.2.2 jdolecek is_tiny = FALSE; 345 1.1.2.2 jdolecek Dbl_decrement(opnd3p1,opnd3p2); 346 1.1.2.2 jdolecek } 347 1.1.2.2 jdolecek break; 348 1.1.2.2 jdolecek case ROUNDNEAREST: 349 1.1.2.2 jdolecek if (guardbit && (stickybit || 350 1.1.2.2 jdolecek Dbl_isone_lowmantissap2(opnd3p2))) { 351 1.1.2.2 jdolecek Dbl_increment(opnd3p1,opnd3p2); 352 1.1.2.2 jdolecek if (Dbl_isone_hiddenoverflow(opnd3p1)) 353 1.1.2.2 jdolecek is_tiny = FALSE; 354 1.1.2.2 jdolecek Dbl_decrement(opnd3p1,opnd3p2); 355 1.1.2.2 jdolecek } 356 1.1.2.2 jdolecek break; 357 1.1.2.2 jdolecek } 358 1.1.2.2 jdolecek } 359 1.1.2.2 jdolecek 360 1.1.2.2 jdolecek /* 361 1.1.2.2 jdolecek * denormalize result or set to signed zero 362 1.1.2.2 jdolecek */ 363 1.1.2.2 jdolecek stickybit = inexact; 364 1.1.2.2 jdolecek Dbl_denormalize(opnd3p1,opnd3p2,dest_exponent,guardbit, 365 1.1.2.2 jdolecek stickybit,inexact); 366 1.1.2.2 jdolecek 367 1.1.2.2 jdolecek /* return zero or smallest number */ 368 1.1.2.2 jdolecek if (inexact) { 369 1.1.2.2 jdolecek switch (Rounding_mode()) { 370 1.1.2.2 jdolecek case ROUNDPLUS: 371 1.1.2.2 jdolecek if (Dbl_iszero_sign(resultp1)) { 372 1.1.2.2 jdolecek Dbl_increment(opnd3p1,opnd3p2); 373 1.1.2.2 jdolecek } 374 1.1.2.2 jdolecek break; 375 1.1.2.2 jdolecek case ROUNDMINUS: 376 1.1.2.2 jdolecek if (Dbl_isone_sign(resultp1)) { 377 1.1.2.2 jdolecek Dbl_increment(opnd3p1,opnd3p2); 378 1.1.2.2 jdolecek } 379 1.1.2.2 jdolecek break; 380 1.1.2.2 jdolecek case ROUNDNEAREST: 381 1.1.2.2 jdolecek if (guardbit && (stickybit || 382 1.1.2.2 jdolecek Dbl_isone_lowmantissap2(opnd3p2))) { 383 1.1.2.2 jdolecek Dbl_increment(opnd3p1,opnd3p2); 384 1.1.2.2 jdolecek } 385 1.1.2.2 jdolecek break; 386 1.1.2.2 jdolecek } 387 1.1.2.2 jdolecek if (is_tiny) Set_underflowflag(); 388 1.1.2.2 jdolecek } 389 1.1.2.2 jdolecek Dbl_set_exponentmantissa(resultp1,resultp2,opnd3p1,opnd3p2); 390 1.1.2.2 jdolecek } 391 1.1.2.2 jdolecek else Dbl_set_exponent(resultp1,dest_exponent); 392 1.1.2.2 jdolecek /* check for inexact */ 393 1.1.2.2 jdolecek Dbl_copytoptr(resultp1,resultp2,dstptr); 394 1.1.2.2 jdolecek if (inexact) { 395 1.1.2.2 jdolecek if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION); 396 1.1.2.2 jdolecek else Set_inexactflag(); 397 1.1.2.2 jdolecek } 398 1.1.2.2 jdolecek return(NOEXCEPTION); 399 1.1.2.2 jdolecek } 400
Indexes created Tue Oct 14 21:09:58 GMT 2025