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author | Hans Hagen <pragma@wxs.nl> | 2023-04-27 00:04:07 +0200 |
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committer | Context Git Mirror Bot <phg@phi-gamma.net> | 2023-04-27 00:04:07 +0200 |
commit | 6b25a7a970ba9553adf8077ef2eecb50a5d77818 (patch) | |
tree | f06e40077ba9e55af4bf6cab52313f79f8ea84a8 /source/luametatex/source/libraries/softposit/source/p8_sub.c | |
parent | 657457ef4a08c1f000f272e00f654f4064cc37bd (diff) | |
download | context-6b25a7a970ba9553adf8077ef2eecb50a5d77818.tar.gz |
2023-04-26 23:31:00
Diffstat (limited to 'source/luametatex/source/libraries/softposit/source/p8_sub.c')
-rw-r--r-- | source/luametatex/source/libraries/softposit/source/p8_sub.c | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/softposit/source/p8_sub.c b/source/luametatex/source/libraries/softposit/source/p8_sub.c new file mode 100644 index 000000000..31c05d874 --- /dev/null +++ b/source/luametatex/source/libraries/softposit/source/p8_sub.c @@ -0,0 +1,88 @@ + +/*============================================================================ + +This C source file is part of the SoftPosit Posit Arithmetic Package +by S. H. Leong (Cerlane). + +Copyright 2017 A*STAR. All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are met: + + 1. Redistributions of source code must retain the above copyright notice, + this list of conditions, and the following disclaimer. + + 2. Redistributions in binary form must reproduce the above copyright notice, + this list of conditions, and the following disclaimer in the documentation + and/or other materials provided with the distribution. + + 3. Neither the name of the University nor the names of its contributors may + be used to endorse or promote products derived from this software without + specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY +EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED +WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE +DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY +DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES +(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND +ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS +SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +=============================================================================*/ + + +#include "platform.h" +#include "internals.h" + +posit8_t p8_sub( posit8_t a, posit8_t b ){ + + union ui8_p8 uA, uB; + uint_fast8_t uiA, uiB; + union ui8_p8 uZ; + + uA.p = a; + uiA = uA.ui; + uB.p = b; + uiB = uB.ui; + + + +#ifdef SOFTPOSIT_EXACT + uZ.ui.exact = (uiA.ui.exact & uiB.ui.exact); +#endif + + //infinity + if ( uiA==0x80 || uiB==0x80 ){ +#ifdef SOFTPOSIT_EXACT + uZ.ui.v = 0x80; + uZ.ui.exact = 0; +#else + uZ.ui = 0x80; +#endif + return uZ.p; + } + //Zero + else if ( uiA==0 || uiB==0 ){ +#ifdef SOFTPOSIT_EXACT + uZ.ui.v = (uiA | -uiB); + uZ.ui.exact = 0; +#else + uZ.ui = (uiA | -uiB); +#endif + return uZ.p; + } + + //different signs + if (signP8UI(uiA^uiB)) + return softposit_addMagsP8(uiA, (-uiB & 0xFF)); + else + return softposit_subMagsP8(uiA, (-uiB & 0xFF)); + + + + +} + |