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 static inline union ieee754sp ieee754sp_nan_fdp(int xs, u64 xm) 26 { 27 return buildsp(xs, SP_EMAX + 1 + SP_EBIAS, 28 xm >> (DP_FBITS - SP_FBITS)); 29 } 30 31 union ieee754sp ieee754sp_fdp(union ieee754dp x) 32 { 33 union ieee754sp y; 34 u32 rm; 35 36 COMPXDP; 37 COMPYSP; 38 39 EXPLODEXDP; 40 41 ieee754_clearcx(); 42 43 FLUSHXDP; 44 45 switch (xc) { 46 case IEEE754_CLASS_SNAN: 47 return ieee754sp_nanxcpt(ieee754sp_nan_fdp(xs, xm)); 48 49 case IEEE754_CLASS_QNAN: 50 y = ieee754sp_nan_fdp(xs, xm); 51 EXPLODEYSP; 52 if (!ieee754_class_nan(yc)) 53 y = ieee754sp_indef(); 54 return y; 55 56 case IEEE754_CLASS_INF: 57 return ieee754sp_inf(xs); 58 59 case IEEE754_CLASS_ZERO: 60 return ieee754sp_zero(xs); 61 62 case IEEE754_CLASS_DNORM: 63 /* can't possibly be sp representable */ 64 ieee754_setcx(IEEE754_UNDERFLOW); 65 ieee754_setcx(IEEE754_INEXACT); 66 if ((ieee754_csr.rm == FPU_CSR_RU && !xs) || 67 (ieee754_csr.rm == FPU_CSR_RD && xs)) 68 return ieee754sp_mind(xs); 69 return ieee754sp_zero(xs); 70 71 case IEEE754_CLASS_NORM: 72 break; 73 } 74 75 /* 76 * Convert from DP_FBITS to SP_FBITS+3 with sticky right shift. 77 */ 78 rm = (xm >> (DP_FBITS - (SP_FBITS + 3))) | 79 ((xm << (64 - (DP_FBITS - (SP_FBITS + 3)))) != 0); 80 81 return ieee754sp_format(xs, xe, rm); 82 } 83