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/*

===============================================================================

This C source file is part of TestFloat, Release 2a, a package of programs

for testing the correctness of floating-point arithmetic complying to the

IEC/IEEE Standard for Floating-Point.

Written by John R. Hauser.  More information is available through the Web

page `http://HTTP.CS.Berkeley.EDU/~jhauser/arithmetic/TestFloat.html'.

THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE.  Although reasonable effort

has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT

TIMES RESULT IN INCORRECT BEHAVIOR.  USE OF THIS SOFTWARE IS RESTRICTED TO

PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY

AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE.

Derivative works are acceptable, even for commercial purposes, so long as

(1) they include prominent notice that the work is derivative, and (2) they

include prominent notice akin to these four paragraphs for those parts of

this code that are retained.

Modified for use with or1ksim's testsuite.

Contributor Julius Baxter <julius.baxter@orsoc.se>

===============================================================================

*/

#include "milieu.h"

#include "systflags.h"

#include "spr-defs.h"

//#include <stdio.h>

// Float flag values, from softfloat.h

enum {

    float_flag_invalid   =  1,

    float_flag_divbyzero =  4,

    float_flag_overflow  =  8,

    float_flag_underflow = 16,

    float_flag_inexact   = 32

};

/*

-------------------------------------------------------------------------------

Clears the system's IEC/IEEE floating-point exception flags.  Returns the

previous value of the flags.

-------------------------------------------------------------------------------

*/

int8 syst_float_flags_clear( void )

{

  // Read the FPCSR

  unsigned int spr = SPR_FPCSR;

  unsigned int value;

  int8 flags = 0;

  // Read the SPR

  asm("l.mfspr\t\t%0,%1,0" : "=r" (value) : "r" (spr));

  // Extract the flags from OR1K's FPCSR, put into testfloat's flags format  

  if (value & SPR_FPCSR_IXF)

    flags |= float_flag_inexact;

  if (value & SPR_FPCSR_UNF)

    flags |= float_flag_underflow;

  if (value & SPR_FPCSR_OVF)

    flags |= float_flag_overflow;

  if (value & SPR_FPCSR_DZF)

    flags |= float_flag_divbyzero;

  if (value & SPR_FPCSR_IVF)

    flags |= float_flag_invalid;

  //  printf("testfloat: getting flags, FPCSR: 0x%x, softfloatflags: 0x%x\n", 

  //         value & SPR_FPCSR_ALLF, flags);

  // Clear flags in FPCSR

  value &= ~(SPR_FPCSR_ALLF);

  // Write value back to FPCSR

  asm("l.mtspr\t\t%0,%1,0": : "r" (spr), "r" (value));

  return flags;

}