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author | Xavier Leroy <xavier.leroy@inria.fr> | 2015-03-14 10:35:25 +0100 |
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committer | Xavier Leroy <xavier.leroy@inria.fr> | 2015-03-14 10:35:25 +0100 |
commit | 890141acb930bdb6f985244f81833331382f7b66 (patch) | |
tree | cc32d6be06feaebca5076727f5531959e8e37530 /runtime/c/i64_utof.c | |
parent | 67e8b783c7e794d995675a332f118533e6a9b14a (diff) | |
parent | 3e01154d693e1c457e1e974f5e9ebaa4601050aa (diff) | |
download | compcert-890141acb930bdb6f985244f81833331382f7b66.tar.gz compcert-890141acb930bdb6f985244f81833331382f7b66.zip |
Merge branch 'master' into struct-passing
Diffstat (limited to 'runtime/c/i64_utof.c')
-rw-r--r-- | runtime/c/i64_utof.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/runtime/c/i64_utof.c b/runtime/c/i64_utof.c new file mode 100644 index 00000000..87b85bfc --- /dev/null +++ b/runtime/c/i64_utof.c @@ -0,0 +1,55 @@ +/***************************************************************** + * + * The Compcert verified compiler + * + * Xavier Leroy, INRIA Paris-Rocquencourt + * + * Copyright (c) 2013 Institut National de Recherche en Informatique et + * en Automatique. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * 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. + * * Neither the name of the <organization> 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 COPYRIGHT HOLDERS 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 <COPYRIGHT + * HOLDER> 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. + * + **********************************************************************/ + +/* Helper functions for 64-bit integer arithmetic. Reference C implementation */ + +#include "i64.h" + +/* Conversion from unsigned int64 to float32 */ + +float __i64_utof(unsigned long long x) +{ + if (x >= 1ULL << 53) { + /* x is large enough that double rounding can occur. + Nudge x away from the points where double rounding occurs + (the "round to odd" technique) */ + unsigned delta = ((unsigned) x & 0x7FF) + 0x7FF; + x = (x | delta) & ~0x7FFULL; + } + /* Convert to double */ + unsigned xl = x, xh = x >> 32; + double r = (double) xl + 0x1.0p32 * (double) xh; + /* Round to single */ + return (float) r; +} |