| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 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 | x = ieee754dp_nanxcpt(x); |
| 48 | EXPLODEXDP; |
| 49 | /* fall through */ |
| 50 | |
| 51 | case IEEE754_CLASS_QNAN: |
| 52 | y = ieee754sp_nan_fdp(xs, xm); |
| 53 | if (!ieee754_csr.nan2008) { |
| 54 | EXPLODEYSP; |
| 55 | if (!ieee754_class_nan(yc)) |
| 56 | y = ieee754sp_indef(); |
| 57 | } |
| 58 | return y; |
| 59 | |
| 60 | case IEEE754_CLASS_INF: |
| 61 | return ieee754sp_inf(xs); |
| 62 | |
| 63 | case IEEE754_CLASS_ZERO: |
| 64 | return ieee754sp_zero(xs); |
| 65 | |
| 66 | case IEEE754_CLASS_DNORM: |
| 67 | /* can't possibly be sp representable */ |
| 68 | ieee754_setcx(IEEE754_UNDERFLOW); |
| 69 | ieee754_setcx(IEEE754_INEXACT); |
| 70 | if ((ieee754_csr.rm == FPU_CSR_RU && !xs) || |
| 71 | (ieee754_csr.rm == FPU_CSR_RD && xs)) |
| 72 | return ieee754sp_mind(xs); |
| 73 | return ieee754sp_zero(xs); |
| 74 | |
| 75 | case IEEE754_CLASS_NORM: |
| 76 | break; |
| 77 | } |
| 78 | |
| 79 | /* |
| 80 | * Convert from DP_FBITS to SP_FBITS+3 with sticky right shift. |
| 81 | */ |
| 82 | rm = (xm >> (DP_FBITS - (SP_FBITS + 3))) | |
| 83 | ((xm << (64 - (DP_FBITS - (SP_FBITS + 3)))) != 0); |
| 84 | |
| 85 | return ieee754sp_format(xs, xe, rm); |
| 86 | } |