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- /* IEEE754 floating point arithmetic
- * double precision: common utilities
- */
- /*
- * MIPS floating point support
- * Copyright (C) 1994-2000 Algorithmics Ltd.
- *
- * This program is free software; you can distribute it and/or modify it
- * under the terms of the GNU General Public License (Version 2) as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope 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.,
- * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- */
- #include "ieee754dp.h"
- int ieee754dp_tint(union ieee754dp x)
- {
- u64 residue;
- int round;
- int sticky;
- int odd;
- COMPXDP;
- ieee754_clearcx();
- EXPLODEXDP;
- FLUSHXDP;
- switch (xc) {
- case IEEE754_CLASS_SNAN:
- case IEEE754_CLASS_QNAN:
- case IEEE754_CLASS_INF:
- ieee754_setcx(IEEE754_INVALID_OPERATION);
- return ieee754si_indef();
- case IEEE754_CLASS_ZERO:
- return 0;
- case IEEE754_CLASS_DNORM:
- case IEEE754_CLASS_NORM:
- break;
- }
- if (xe > 31) {
- /* Set invalid. We will only use overflow for floating
- point overflow */
- ieee754_setcx(IEEE754_INVALID_OPERATION);
- return ieee754si_indef();
- }
- /* oh gawd */
- if (xe > DP_FBITS) {
- xm <<= xe - DP_FBITS;
- } else if (xe < DP_FBITS) {
- if (xe < -1) {
- residue = xm;
- round = 0;
- sticky = residue != 0;
- xm = 0;
- } else {
- residue = xm << (64 - DP_FBITS + xe);
- round = (residue >> 63) != 0;
- sticky = (residue << 1) != 0;
- xm >>= DP_FBITS - xe;
- }
- /* Note: At this point upper 32 bits of xm are guaranteed
- to be zero */
- odd = (xm & 0x1) != 0x0;
- switch (ieee754_csr.rm) {
- case FPU_CSR_RN:
- if (round && (sticky || odd))
- xm++;
- break;
- case FPU_CSR_RZ:
- break;
- case FPU_CSR_RU: /* toward +Infinity */
- if ((round || sticky) && !xs)
- xm++;
- break;
- case FPU_CSR_RD: /* toward -Infinity */
- if ((round || sticky) && xs)
- xm++;
- break;
- }
- /* look for valid corner case 0x80000000 */
- if ((xm >> 31) != 0 && (xs == 0 || xm != 0x80000000)) {
- /* This can happen after rounding */
- ieee754_setcx(IEEE754_INVALID_OPERATION);
- return ieee754si_indef();
- }
- if (round || sticky)
- ieee754_setcx(IEEE754_INEXACT);
- }
- if (xs)
- return -xm;
- else
- return xm;
- }
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