1b8e80941Smrg/* 2b8e80941Smrg * Copyright © 2014 Intel Corporation 3b8e80941Smrg * 4b8e80941Smrg * Permission is hereby granted, free of charge, to any person obtaining a 5b8e80941Smrg * copy of this software and associated documentation files (the "Software"), 6b8e80941Smrg * to deal in the Software without restriction, including without limitation 7b8e80941Smrg * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8b8e80941Smrg * and/or sell copies of the Software, and to permit persons to whom the 9b8e80941Smrg * Software is furnished to do so, subject to the following conditions: 10b8e80941Smrg * 11b8e80941Smrg * The above copyright notice and this permission notice (including the next 12b8e80941Smrg * paragraph) shall be included in all copies or substantial portions of the 13b8e80941Smrg * Software. 14b8e80941Smrg * 15b8e80941Smrg * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16b8e80941Smrg * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17b8e80941Smrg * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18b8e80941Smrg * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19b8e80941Smrg * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 20b8e80941Smrg * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 21b8e80941Smrg * IN THE SOFTWARE. 22b8e80941Smrg */ 23b8e80941Smrg#include "brw_reg.h" 24b8e80941Smrg 25b8e80941Smrgunion fu { 26b8e80941Smrg float f; 27b8e80941Smrg unsigned u; 28b8e80941Smrg struct { 29b8e80941Smrg unsigned mantissa:23; 30b8e80941Smrg unsigned exponent:8; 31b8e80941Smrg unsigned sign:1; 32b8e80941Smrg } s; 33b8e80941Smrg}; 34b8e80941Smrg 35b8e80941Smrgint 36b8e80941Smrgbrw_float_to_vf(float f) 37b8e80941Smrg{ 38b8e80941Smrg union fu fu = { .f = f }; 39b8e80941Smrg 40b8e80941Smrg /* ±0.0f is special cased. */ 41b8e80941Smrg if (f == 0.0f) 42b8e80941Smrg return fu.s.sign << 7; 43b8e80941Smrg 44b8e80941Smrg unsigned mantissa = fu.s.mantissa >> (23 - 4); 45b8e80941Smrg unsigned exponent = fu.s.exponent - (127 - 3); 46b8e80941Smrg unsigned vf = (fu.s.sign << 7) | (exponent << 4) | mantissa; 47b8e80941Smrg 48b8e80941Smrg /* 0.125 would have had the same representation as 0.0, so reject it. */ 49b8e80941Smrg if ((vf & 0x7f) == 0) 50b8e80941Smrg return -1; 51b8e80941Smrg 52b8e80941Smrg /* Make sure the mantissa fits in 4-bits and the exponent in 3-bits. */ 53b8e80941Smrg if (fu.u & 0x7ffff || exponent > 7) 54b8e80941Smrg return -1; 55b8e80941Smrg 56b8e80941Smrg return vf; 57b8e80941Smrg} 58b8e80941Smrg 59b8e80941Smrgfloat 60b8e80941Smrgbrw_vf_to_float(unsigned char vf) 61b8e80941Smrg{ 62b8e80941Smrg union fu fu; 63b8e80941Smrg 64b8e80941Smrg /* ±0.0f is special cased. */ 65b8e80941Smrg if (vf == 0x00 || vf == 0x80) { 66b8e80941Smrg fu.u = vf << 24; 67b8e80941Smrg return fu.f; 68b8e80941Smrg } 69b8e80941Smrg 70b8e80941Smrg fu.s.sign = vf >> 7; 71b8e80941Smrg fu.s.exponent = ((vf & 0x70) >> 4) + (127 - 3); 72b8e80941Smrg fu.s.mantissa = (vf & 0xf) << (23 - 4); 73b8e80941Smrg 74b8e80941Smrg return fu.f; 75b8e80941Smrg} 76