diff options
Diffstat (limited to 'third_party/bearssl/src/i31_ninv31.c')
-rw-r--r-- | third_party/bearssl/src/i31_ninv31.c | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/third_party/bearssl/src/i31_ninv31.c b/third_party/bearssl/src/i31_ninv31.c new file mode 100644 index 0000000..dd83c96 --- /dev/null +++ b/third_party/bearssl/src/i31_ninv31.c @@ -0,0 +1,39 @@ +/* + * Copyright (c) 2016 Thomas Pornin <[email protected]> + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +#include "inner.h" + +/* see inner.h */ +uint32_t +br_i31_ninv31(uint32_t x) +{ + uint32_t y; + + y = 2 - x; + y *= 2 - y * x; + y *= 2 - y * x; + y *= 2 - y * x; + y *= 2 - y * x; + return MUX(x & 1, -y, 0) & 0x7FFFFFFF; +} |