// *****************************************************************
//
//               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
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//       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
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// *********************************************************************

// 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)