1 /* IEEE754 floating point arithmetic 2 * single precision 3 */ 4 /* 5 * MIPS floating point support 6 * Copyright (C) 1994-2000 Algorithmics Ltd. 7 * 8 * This program is free software; you can distribute it and/or modify it 9 * under the terms of the GNU General Public License (Version 2) as 10 * published by the Free Software Foundation. 11 * 12 * This program is distributed in the hope it will be useful, but WITHOUT 13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 15 * for more details. 16 * 17 * You should have received a copy of the GNU General Public License along 18 * with this program; if not, write to the Free Software Foundation, Inc., 19 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 */ 21 22 #include "ieee754sp.h" 23 #include "ieee754dp.h" 24 25 s64 ieee754sp_tlong(union ieee754sp x) 26 { 27 u32 residue; 28 int round; 29 int sticky; 30 int odd; 31 32 COMPXDP; /* <-- need 64-bit mantissa tmp */ 33 34 ieee754_clearcx(); 35 36 EXPLODEXSP; 37 FLUSHXSP; 38 39 switch (xc) { 40 case IEEE754_CLASS_SNAN: 41 case IEEE754_CLASS_QNAN: 42 case IEEE754_CLASS_INF: 43 ieee754_setcx(IEEE754_INVALID_OPERATION); 44 return ieee754di_indef(); 45 46 case IEEE754_CLASS_ZERO: 47 return 0; 48 49 case IEEE754_CLASS_DNORM: 50 case IEEE754_CLASS_NORM: 51 break; 52 } 53 if (xe >= 63) { 54 /* look for valid corner case */ 55 if (xe == 63 && xs && xm == SP_HIDDEN_BIT) 56 return -0x8000000000000000LL; 57 /* Set invalid. We will only use overflow for floating 58 point overflow */ 59 ieee754_setcx(IEEE754_INVALID_OPERATION); 60 return ieee754di_indef(); 61 } 62 /* oh gawd */ 63 if (xe > SP_FBITS) { 64 xm <<= xe - SP_FBITS; 65 } else if (xe < SP_FBITS) { 66 if (xe < -1) { 67 residue = xm; 68 round = 0; 69 sticky = residue != 0; 70 xm = 0; 71 } else { 72 residue = xm << (32 - SP_FBITS + xe); 73 round = (residue >> 31) != 0; 74 sticky = (residue << 1) != 0; 75 xm >>= SP_FBITS - xe; 76 } 77 odd = (xm & 0x1) != 0x0; 78 switch (ieee754_csr.rm) { 79 case FPU_CSR_RN: 80 if (round && (sticky || odd)) 81 xm++; 82 break; 83 case FPU_CSR_RZ: 84 break; 85 case FPU_CSR_RU: /* toward +Infinity */ 86 if ((round || sticky) && !xs) 87 xm++; 88 break; 89 case FPU_CSR_RD: /* toward -Infinity */ 90 if ((round || sticky) && xs) 91 xm++; 92 break; 93 } 94 if ((xm >> 63) != 0) { 95 /* This can happen after rounding */ 96 ieee754_setcx(IEEE754_INVALID_OPERATION); 97 return ieee754di_indef(); 98 } 99 if (round || sticky) 100 ieee754_setcx(IEEE754_INEXACT); 101 } 102 if (xs) 103 return -xm; 104 else 105 return xm; 106 } 107