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Diffstat (limited to 'runtime/x86_32/i64_sar.S')
-rw-r--r-- | runtime/x86_32/i64_sar.S | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/runtime/x86_32/i64_sar.S b/runtime/x86_32/i64_sar.S new file mode 100644 index 00000000..cf2233b1 --- /dev/null +++ b/runtime/x86_32/i64_sar.S @@ -0,0 +1,60 @@ +// ***************************************************************** +// +// 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" + +// Shift right signed + +// Note: IA32 shift instructions treat their amount (in %cl) modulo 32 + +FUNCTION(__i64_sar) + movl 12(%esp), %ecx // ecx = shift amount, treated mod 64 + testb $32, %cl + jne 1f + // shift amount < 32 + movl 4(%esp), %eax + movl 8(%esp), %edx + shrdl %cl, %edx, %eax // eax = low(XH:XL >> amount) + sarl %cl, %edx // edx = XH >> amount (signed) + ret + // shift amount >= 32 +1: movl 8(%esp), %eax + movl %eax, %edx + sarl %cl, %eax // eax = XH >> (amount - 32) + sarl $31, %edx // edx = sign of X + ret +ENDFUNCTION(__i64_sar) + |