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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 | // SPDX-License-Identifier: GPL-2.0-or-later
/*
* Linux/PA-RISC Project (http://www.parisc-linux.org/)
*
* Floating-point emulation code
* Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org>
*/
/*
* BEGIN_DESC
*
* File:
* @(#) pa/spmath/sfmpy.c $Revision: 1.1 $
*
* Purpose:
* Single Precision Floating-point Multiply
*
* External Interfaces:
* sgl_fmpy(srcptr1,srcptr2,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"
/*
* Single Precision Floating-point Multiply
*/
int
sgl_fmpy(
sgl_floating_point *srcptr1,
sgl_floating_point *srcptr2,
sgl_floating_point *dstptr,
unsigned int *status)
{
register unsigned int opnd1, opnd2, opnd3, result;
register int dest_exponent, count;
register boolean inexact = FALSE, guardbit = FALSE, stickybit = FALSE;
boolean is_tiny;
opnd1 = *srcptr1;
opnd2 = *srcptr2;
/*
* set sign bit of result
*/
if (Sgl_sign(opnd1) ^ Sgl_sign(opnd2)) Sgl_setnegativezero(result);
else Sgl_setzero(result);
/*
* check first operand for NaN's or infinity
*/
if (Sgl_isinfinity_exponent(opnd1)) {
if (Sgl_iszero_mantissa(opnd1)) {
if (Sgl_isnotnan(opnd2)) {
if (Sgl_iszero_exponentmantissa(opnd2)) {
/*
* invalid since operands are infinity
* and zero
*/
if (Is_invalidtrap_enabled())
return(INVALIDEXCEPTION);
Set_invalidflag();
Sgl_makequietnan(result);
*dstptr = result;
return(NOEXCEPTION);
}
/*
* return infinity
*/
Sgl_setinfinity_exponentmantissa(result);
*dstptr = result;
return(NOEXCEPTION);
}
}
else {
/*
* is NaN; signaling or quiet?
*/
if (Sgl_isone_signaling(opnd1)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Sgl_set_quiet(opnd1);
}
/*
* is second operand a signaling NaN?
*/
else if (Sgl_is_signalingnan(opnd2)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Sgl_set_quiet(opnd2);
*dstptr = opnd2;
return(NOEXCEPTION);
}
/*
* return quiet NaN
*/
*dstptr = opnd1;
return(NOEXCEPTION);
}
}
/*
* check second operand for NaN's or infinity
*/
if (Sgl_isinfinity_exponent(opnd2)) {
if (Sgl_iszero_mantissa(opnd2)) {
if (Sgl_iszero_exponentmantissa(opnd1)) {
/* invalid since operands are zero & infinity */
if (Is_invalidtrap_enabled())
return(INVALIDEXCEPTION);
Set_invalidflag();
Sgl_makequietnan(opnd2);
*dstptr = opnd2;
return(NOEXCEPTION);
}
/*
* return infinity
*/
Sgl_setinfinity_exponentmantissa(result);
*dstptr = result;
return(NOEXCEPTION);
}
/*
* is NaN; signaling or quiet?
*/
if (Sgl_isone_signaling(opnd2)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
/* make NaN quiet */
Set_invalidflag();
Sgl_set_quiet(opnd2);
}
/*
* return quiet NaN
*/
*dstptr = opnd2;
return(NOEXCEPTION);
}
/*
* Generate exponent
*/
dest_exponent = Sgl_exponent(opnd1) + Sgl_exponent(opnd2) - SGL_BIAS;
/*
* Generate mantissa
*/
if (Sgl_isnotzero_exponent(opnd1)) {
/* set hidden bit */
Sgl_clear_signexponent_set_hidden(opnd1);
}
else {
/* check for zero */
if (Sgl_iszero_mantissa(opnd1)) {
Sgl_setzero_exponentmantissa(result);
*dstptr = result;
return(NOEXCEPTION);
}
/* is denormalized, adjust exponent */
Sgl_clear_signexponent(opnd1);
Sgl_leftshiftby1(opnd1);
Sgl_normalize(opnd1,dest_exponent);
}
/* opnd2 needs to have hidden bit set with msb in hidden bit */
if (Sgl_isnotzero_exponent(opnd2)) {
Sgl_clear_signexponent_set_hidden(opnd2);
}
else {
/* check for zero */
if (Sgl_iszero_mantissa(opnd2)) {
Sgl_setzero_exponentmantissa(result);
*dstptr = result;
return(NOEXCEPTION);
}
/* is denormalized; want to normalize */
Sgl_clear_signexponent(opnd2);
Sgl_leftshiftby1(opnd2);
Sgl_normalize(opnd2,dest_exponent);
}
/* Multiply two source mantissas together */
Sgl_leftshiftby4(opnd2); /* make room for guard bits */
Sgl_setzero(opnd3);
/*
* Four bits at a time are inspected in each loop, and a
* simple shift and add multiply algorithm is used.
*/
for (count=1;count<SGL_P;count+=4) {
stickybit |= Slow4(opnd3);
Sgl_rightshiftby4(opnd3);
if (Sbit28(opnd1)) Sall(opnd3) += (Sall(opnd2) << 3);
if (Sbit29(opnd1)) Sall(opnd3) += (Sall(opnd2) << 2);
if (Sbit30(opnd1)) Sall(opnd3) += (Sall(opnd2) << 1);
if (Sbit31(opnd1)) Sall(opnd3) += Sall(opnd2);
Sgl_rightshiftby4(opnd1);
}
/* make sure result is left-justified */
if (Sgl_iszero_sign(opnd3)) {
Sgl_leftshiftby1(opnd3);
}
else {
/* result mantissa >= 2. */
dest_exponent++;
}
/* check for denormalized result */
while (Sgl_iszero_sign(opnd3)) {
Sgl_leftshiftby1(opnd3);
dest_exponent--;
}
/*
* check for guard, sticky and inexact bits
*/
stickybit |= Sgl_all(opnd3) << (SGL_BITLENGTH - SGL_EXP_LENGTH + 1);
guardbit = Sbit24(opnd3);
inexact = guardbit | stickybit;
/* re-align mantissa */
Sgl_rightshiftby8(opnd3);
/*
* round result
*/
if (inexact && (dest_exponent>0 || Is_underflowtrap_enabled())) {
Sgl_clear_signexponent(opnd3);
switch (Rounding_mode()) {
case ROUNDPLUS:
if (Sgl_iszero_sign(result))
Sgl_increment(opnd3);
break;
case ROUNDMINUS:
if (Sgl_isone_sign(result))
Sgl_increment(opnd3);
break;
case ROUNDNEAREST:
if (guardbit) {
if (stickybit || Sgl_isone_lowmantissa(opnd3))
Sgl_increment(opnd3);
}
}
if (Sgl_isone_hidden(opnd3)) dest_exponent++;
}
Sgl_set_mantissa(result,opnd3);
/*
* Test for overflow
*/
if (dest_exponent >= SGL_INFINITY_EXPONENT) {
/* trap if OVERFLOWTRAP enabled */
if (Is_overflowtrap_enabled()) {
/*
* 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);
}
inexact = TRUE;
Set_overflowflag();
/* 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()) {
/*
* 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);
}
/* Determine if should set underflow flag */
is_tiny = TRUE;
if (dest_exponent == 0 && inexact) {
switch (Rounding_mode()) {
case ROUNDPLUS:
if (Sgl_iszero_sign(result)) {
Sgl_increment(opnd3);
if (Sgl_isone_hiddenoverflow(opnd3))
is_tiny = FALSE;
Sgl_decrement(opnd3);
}
break;
case ROUNDMINUS:
if (Sgl_isone_sign(result)) {
Sgl_increment(opnd3);
if (Sgl_isone_hiddenoverflow(opnd3))
is_tiny = FALSE;
Sgl_decrement(opnd3);
}
break;
case ROUNDNEAREST:
if (guardbit && (stickybit ||
Sgl_isone_lowmantissa(opnd3))) {
Sgl_increment(opnd3);
if (Sgl_isone_hiddenoverflow(opnd3))
is_tiny = FALSE;
Sgl_decrement(opnd3);
}
break;
}
}
/*
* denormalize result or set to signed zero
*/
stickybit = inexact;
Sgl_denormalize(opnd3,dest_exponent,guardbit,stickybit,inexact);
/* return zero or smallest number */
if (inexact) {
switch (Rounding_mode()) {
case ROUNDPLUS:
if (Sgl_iszero_sign(result)) {
Sgl_increment(opnd3);
}
break;
case ROUNDMINUS:
if (Sgl_isone_sign(result)) {
Sgl_increment(opnd3);
}
break;
case ROUNDNEAREST:
if (guardbit && (stickybit ||
Sgl_isone_lowmantissa(opnd3))) {
Sgl_increment(opnd3);
}
break;
}
if (is_tiny) Set_underflowflag();
}
Sgl_set_exponentmantissa(result,opnd3);
}
else Sgl_set_exponent(result,dest_exponent);
*dstptr = result;
/* check for inexact */
if (inexact) {
if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
else Set_inexactflag();
}
return(NOEXCEPTION);
}
|