

/* BEEBS newlib ef_fmod implementation

   ====================================================
   Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.

   Developed at SunPro, a Sun Microsystems, Inc. business.
   Permission to use, copy, modify, and distribute this
   software is freely granted, provided that this notice
   is preserved.
   ====================================================

   Copyright (C) 2014 Embecosm Limited and University of Bristol

   Contributor Pierre Langlois <pierre.langlois@embecosm.com>

   This file is part of the Bristol/Embecosm Embedded Benchmark Suite.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program. If not, see <http://www.gnu.org/licenses/>. */

#include "support.h"
#include <stdint.h>

typedef union
{
  float value;
  uint32_t word;
} ieee_float_shape_type;

#define GET_FLOAT_WORD(i,d)					\
{                                                               \
  ieee_float_shape_type gf_u;					\
  gf_u.value = (d);						\
  (i) = gf_u.word;                                              \
}

#define SET_FLOAT_WORD(d,i)					\
{                                                               \
  ieee_float_shape_type sf_u;					\
  sf_u.word = (i);						\
  (d) = sf_u.value;                                             \
}

#define FLT_UWORD_IS_FINITE(x) ((x)<0x7f800000L)
#define FLT_UWORD_IS_NAN(x) ((x)>0x7f800000L)
#define FLT_UWORD_IS_ZERO(x) ((x)==0)
#define FLT_UWORD_IS_SUBNORMAL(x) ((x)<0x00800000L)

/*
 * __ieee754_fmodf(x,y)
 * Return x mod y in exact arithmetic
 * Method: shift and subtract
 */

static const float one = 1.0, Zero[] = {0.0, -0.0,};

	float __ieee754_fmodf(float x, float y)
{
        int32_t n,hx,hy,hz,ix,iy,sx,i;

	GET_FLOAT_WORD(hx,x);
	GET_FLOAT_WORD(hy,y);
	sx = hx&0x80000000;		/* sign of x */
	hx ^=sx;		/* |x| */
	hy &= 0x7fffffff;	/* |y| */

    /* purge off exception values */
	if(FLT_UWORD_IS_ZERO(hy)||
	   !FLT_UWORD_IS_FINITE(hx)||
	   FLT_UWORD_IS_NAN(hy))
	    return (x*y)/(x*y);
	if(hx<hy) return x;			/* |x|<|y| return x */
	if(hx==hy)
	    return Zero[(uint32_t)sx>>31];	/* |x|=|y| return x*0*/

    /* Note: y cannot be zero if we reach here. */

    /* determine ix = ilogb(x) */
	if(FLT_UWORD_IS_SUBNORMAL(hx)) {	/* subnormal x */
	    for (ix = -126,i=(hx<<8); i>0; i<<=1) ix -=1;
	} else ix = (hx>>23)-127;

    /* determine iy = ilogb(y) */
	if(FLT_UWORD_IS_SUBNORMAL(hy)) {	/* subnormal y */
	    for (iy = -126,i=(hy<<8); i>=0; i<<=1) iy -=1;
	} else iy = (hy>>23)-127;

    /* set up {hx,lx}, {hy,ly} and align y to x */
	if(ix >= -126)
	    hx = 0x00800000|(0x007fffff&hx);
	else {		/* subnormal x, shift x to normal */
	    n = -126-ix;
	    hx = hx<<n;
	}
	if(iy >= -126)
	    hy = 0x00800000|(0x007fffff&hy);
	else {		/* subnormal y, shift y to normal */
	    n = -126-iy;
	    hy = hy<<n;
	}

    /* fix point fmod */
	n = ix - iy;
	while(n--) {
	    hz=hx-hy;
	    if(hz<0){hx = hx+hx;}
	    else {
	    	if(hz==0) 		/* return sign(x)*0 */
		    return Zero[(uint32_t)sx>>31];
	    	hx = hz+hz;
	    }
	}
	hz=hx-hy;
	if(hz>=0) {hx=hz;}

    /* convert back to floating value and restore the sign */
	if(hx==0) 			/* return sign(x)*0 */
	    return Zero[(uint32_t)sx>>31];
	while(hx<0x00800000) {		/* normalize x */
	    hx = hx+hx;
	    iy -= 1;
	}
	if(iy>= -126) {		/* normalize output */
	    hx = ((hx-0x00800000)|((iy+127)<<23));
	    SET_FLOAT_WORD(x,hx|sx);
	} else {		/* subnormal output */
	    /* If denormals are not supported, this code will generate a
	       zero representation.  */
	    n = -126 - iy;
	    hx >>= n;
	    SET_FLOAT_WORD(x,hx|sx);
	    x *= one;		/* create necessary signal */
	}
	return x;		/* exact output */
}

/* This scale factor will be changed to equalise the runtime of the
   benchmarks. */
#define SCALE_FACTOR    (REPEAT_FACTOR >> 0)

/* Tell the compiler not to optimize out calls in BENCHMARK. */
volatile float result = 0;



/* This benchmark does not support verification */

int
verify_benchmark (int res __attribute ((unused)) )
{
  return -1;
}


void
initialise_benchmark (void)
{
}


int
benchmark (void)
{
  result = __ieee754_fmodf(2.2353, 1234.5);
  result = __ieee754_fmodf(3.2515, 2345.6);
  result = __ieee754_fmodf(4.9346, 3456.7);
  result = __ieee754_fmodf(5.2342, 4567.8);
  result = __ieee754_fmodf(6.2352, 5678.9);
  return 0;
}


