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 ieee754_setcx(IEEE754_INVALID_OPERATION); 43 return ieee754di_indef(); 44 45 case IEEE754_CLASS_INF: 46 ieee754_setcx(IEEE754_INVALID_OPERATION); 47 return ieee754di_overflow(xs); 48 49 case IEEE754_CLASS_ZERO: 50 return 0; 51 52 case IEEE754_CLASS_DNORM: 53 case IEEE754_CLASS_NORM: 54 break; 55 } 56 if (xe >= 63) { 57 /* look for valid corner case */ 58 if (xe == 63 && xs && xm == SP_HIDDEN_BIT) 59 return -0x8000000000000000LL; 60 /* Set invalid. We will only use overflow for floating 61 point overflow */ 62 ieee754_setcx(IEEE754_INVALID_OPERATION); 63 return ieee754di_overflow(xs); 64 } 65 /* oh gawd */ 66 if (xe > SP_FBITS) { 67 xm <<= xe - SP_FBITS; 68 } else if (xe < SP_FBITS) { 69 if (xe < -1) { 70 residue = xm; 71 round = 0; 72 sticky = residue != 0; 73 xm = 0; 74 } else { 75 residue = xm << (32 - SP_FBITS + xe); 76 round = (residue >> 31) != 0; 77 sticky = (residue << 1) != 0; 78 xm >>= SP_FBITS - xe; 79 } 80 odd = (xm & 0x1) != 0x0; 81 switch (ieee754_csr.rm) { 82 case FPU_CSR_RN: 83 if (round && (sticky || odd)) 84 xm++; 85 break; 86 case FPU_CSR_RZ: 87 break; 88 case FPU_CSR_RU: /* toward +Infinity */ 89 if ((round || sticky) && !xs) 90 xm++; 91 break; 92 case FPU_CSR_RD: /* toward -Infinity */ 93 if ((round || sticky) && xs) 94 xm++; 95 break; 96 } 97 if ((xm >> 63) != 0) { 98 /* This can happen after rounding */ 99 ieee754_setcx(IEEE754_INVALID_OPERATION); 100 return ieee754di_overflow(xs); 101 } 102 if (round || sticky) 103 ieee754_setcx(IEEE754_INEXACT); 104 } 105 if (xs) 106 return -xm; 107 else 108 return xm; 109 } 110