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author | xleroy <xleroy@fca1b0fc-160b-0410-b1d3-a4f43f01ea2e> | 2013-05-06 08:20:06 +0000 |
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committer | xleroy <xleroy@fca1b0fc-160b-0410-b1d3-a4f43f01ea2e> | 2013-05-06 08:20:06 +0000 |
commit | 9b3388bea495d027aa618118096a8223f6866437 (patch) | |
tree | 3d1b1bf3b1e0af9d094b2b04a2dfbfd7d18d1f58 /runtime/powerpc/i64_stof.s | |
parent | b257a6d283f6f5784cb351856b5dbe8c645a1f6f (diff) | |
download | compcert-9b3388bea495d027aa618118096a8223f6866437.tar.gz compcert-9b3388bea495d027aa618118096a8223f6866437.zip |
Support for in64 -> float conversions w/ correct rounding.
git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@2235 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e
Diffstat (limited to 'runtime/powerpc/i64_stof.s')
-rw-r--r-- | runtime/powerpc/i64_stof.s | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/runtime/powerpc/i64_stof.s b/runtime/powerpc/i64_stof.s new file mode 100644 index 00000000..05b36a78 --- /dev/null +++ b/runtime/powerpc/i64_stof.s @@ -0,0 +1,68 @@ +# ***************************************************************** +# +# 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. PowerPC version. + + .text + +### Conversion from signed long to single float + + .balign 16 + .globl __i64_stof +__i64_stof: + mflr r9 + # Check whether -2^53 <= X < 2^53 + srawi r5, r3, 31 + srawi r6, r3, 21 # (r5,r6) = X >> 53 + addic r6, r6, 1 + addze r5, r5 # (r5,r6) = (X >> 53) + 1 + cmplwi r5, 2 + blt 1f + # X is large enough that double rounding can occur. + # Avoid it by nudging X away from the points where double rounding + # occurs (the "round to odd" technique) + rlwinm r0, r4, 0, 21, 31 # extract bits 0 to 11 of X + addi r0, r0, 0x7FF # r0 = (X & 0x7FF) + 0x7FF + # bit 12 of r0 is 0 if all low 12 bits of X are 0, 1 otherwise + # bits 13-31 of r0 are 0 + or r4, r4, r0 # correct bit number 12 of X + rlwinm r4, r4, 0, 0, 20 # set to 0 bits 0 to 11 of X + # Convert to double, then round to single +1: bl __i64_stod + mtlr r9 + frsp f1, f1 + blr + .type __i64_stof, @function + .size __i64_stof, .-__i64_stof + |