| // Copyright 2016 The SwiftShader Authors. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #include "Half.hpp" |
| |
| namespace sw { |
| |
| half::half(float fp32) |
| { |
| unsigned int fp32i = *(unsigned int*)&fp32; |
| unsigned int sign = (fp32i & 0x80000000) >> 16; |
| unsigned int abs = fp32i & 0x7FFFFFFF; |
| |
| if(abs > 0x47FFEFFF) // Infinity |
| { |
| fp16i = sign | 0x7FFF; |
| } |
| else if(abs < 0x38800000) // Denormal |
| { |
| unsigned int mantissa = (abs & 0x007FFFFF) | 0x00800000; |
| int e = 113 - (abs >> 23); |
| |
| if(e < 24) |
| { |
| abs = mantissa >> e; |
| } |
| else |
| { |
| abs = 0; |
| } |
| |
| fp16i = sign | (abs + 0x00000FFF + ((abs >> 13) & 1)) >> 13; |
| } |
| else |
| { |
| fp16i = sign | (abs + 0xC8000000 + 0x00000FFF + ((abs >> 13) & 1)) >> 13; |
| } |
| } |
| |
| half::operator float() const |
| { |
| unsigned int fp32i; |
| |
| int s = (fp16i >> 15) & 0x00000001; |
| int e = (fp16i >> 10) & 0x0000001F; |
| int m = fp16i & 0x000003FF; |
| |
| if(e == 0) |
| { |
| if(m == 0) |
| { |
| fp32i = s << 31; |
| |
| return (float&)fp32i; |
| } |
| else |
| { |
| while(!(m & 0x00000400)) |
| { |
| m <<= 1; |
| e -= 1; |
| } |
| |
| e += 1; |
| m &= ~0x00000400; |
| } |
| } |
| |
| e = e + (127 - 15); |
| m = m << 13; |
| |
| fp32i = (s << 31) | (e << 23) | m; |
| |
| return (float&)fp32i; |
| } |
| |
| half &half::operator=(half h) |
| { |
| fp16i = h.fp16i; |
| |
| return *this; |
| } |
| |
| |
| half &half::operator=(float f) |
| { |
| *this = half(f); |
| |
| return *this; |
| } |
| |
| } // namespace sw |