1 /* IEEE754 floating point arithmetic 2 * single precision 3 */ 4 /* 5 * MIPS floating point support 6 * Copyright (C) 1994-2000 Algorithmics Ltd. 7 * 8 * ######################################################################## 9 * 10 * This program is free software; you can distribute it and/or modify it 11 * under the terms of the GNU General Public License (Version 2) as 12 * published by the Free Software Foundation. 13 * 14 * This program is distributed in the hope it will be useful, but WITHOUT 15 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 16 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 17 * for more details. 18 * 19 * You should have received a copy of the GNU General Public License along 20 * with this program; if not, write to the Free Software Foundation, Inc., 21 * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA. 22 * 23 * ######################################################################## 24 */ 25 26 27 #include "ieee754sp.h" 28 29 int ieee754sp_tint(union ieee754sp x) 30 { 31 COMPXSP; 32 33 ieee754_clearcx(); 34 35 EXPLODEXSP; 36 FLUSHXSP; 37 38 switch (xc) { 39 case IEEE754_CLASS_SNAN: 40 case IEEE754_CLASS_QNAN: 41 case IEEE754_CLASS_INF: 42 ieee754_setcx(IEEE754_INVALID_OPERATION); 43 return ieee754si_indef(); 44 case IEEE754_CLASS_ZERO: 45 return 0; 46 case IEEE754_CLASS_DNORM: 47 case IEEE754_CLASS_NORM: 48 break; 49 } 50 if (xe >= 31) { 51 /* look for valid corner case */ 52 if (xe == 31 && xs && xm == SP_HIDDEN_BIT) 53 return -0x80000000; 54 /* Set invalid. We will only use overflow for floating 55 point overflow */ 56 ieee754_setcx(IEEE754_INVALID_OPERATION); 57 return ieee754si_indef(); 58 } 59 /* oh gawd */ 60 if (xe > SP_FBITS) { 61 xm <<= xe - SP_FBITS; 62 } else { 63 u32 residue; 64 int round; 65 int sticky; 66 int odd; 67 68 if (xe < -1) { 69 residue = xm; 70 round = 0; 71 sticky = residue != 0; 72 xm = 0; 73 } else { 74 /* Shifting a u32 32 times does not work, 75 * so we do it in two steps. Be aware that xe 76 * may be -1 */ 77 residue = xm << (xe + 1); 78 residue <<= 31 - SP_FBITS; 79 round = (residue >> 31) != 0; 80 sticky = (residue << 1) != 0; 81 xm >>= SP_FBITS - xe; 82 } 83 odd = (xm & 0x1) != 0x0; 84 switch (ieee754_csr.rm) { 85 case IEEE754_RN: 86 if (round && (sticky || odd)) 87 xm++; 88 break; 89 case IEEE754_RZ: 90 break; 91 case IEEE754_RU: /* toward +Infinity */ 92 if ((round || sticky) && !xs) 93 xm++; 94 break; 95 case IEEE754_RD: /* toward -Infinity */ 96 if ((round || sticky) && xs) 97 xm++; 98 break; 99 } 100 if ((xm >> 31) != 0) { 101 /* This can happen after rounding */ 102 ieee754_setcx(IEEE754_INVALID_OPERATION); 103 return ieee754si_indef(); 104 } 105 if (round || sticky) 106 ieee754_setcx(IEEE754_INEXACT); 107 } 108 if (xs) 109 return -xm; 110 else 111 return xm; 112 } 113