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Diffstat (limited to 'runtime/ia32/i64_dtou.S')
| -rw-r--r-- | runtime/ia32/i64_dtou.S | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/runtime/ia32/i64_dtou.S b/runtime/ia32/i64_dtou.S new file mode 100644 index 0000000..cdd2381 --- /dev/null +++ b/runtime/ia32/i64_dtou.S @@ -0,0 +1,76 @@ +// ***************************************************************** +// +// 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. IA32 version. + +#include "sysdeps.h" + +// Conversion float -> unsigned long + +FUNCTION(__i64_dtou) + subl $4, %esp + // Change rounding mode to "round towards zero" + fnstcw 0(%esp) + movw 0(%esp), %ax + movb $12, %ah + movw %ax, 2(%esp) + fldcw 2(%esp) + // Compare argument with 2^63 + fldl 8(%esp) + flds LC1 + fucomp + fnstsw %ax + sahf + jbe 1f // branch if not (ARG < 2^63) + // Argument < 2^63: convert as is + fistpll 8(%esp) + movl 8(%esp), %eax + movl 12(%esp), %edx + jmp 2f + // Argument > 2^63: offset ARG by -2^63, then convert, then offset RES by 2^63 +1: fsubs LC1 + fistpll 8(%esp) + movl 8(%esp), %eax + movl 12(%esp), %edx + addl $0x80000000, %edx + // Restore rounding mode +2: fldcw 0(%esp) + addl $4, %esp + ret + + .p2align 2 +LC1: .long 0x5f000000 // 2^63 in single precision + +ENDFUNCTION(__i64_dtou) +
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