/*
 * Copyright (c) 2019 Actions Semi Co., Inc.
 *
 * SPDX-License-Identifier: Apache-2.0
 */

/* poriting from newlib */

#ifndef __UVISION_VERSION

#include <stdint.h>

typedef union {
  double value;
  struct {
    uint32_t lsw;
    uint32_t msw;
  } parts;
} ieee_double_shape_type;

/* Get two 32 bit ints from a double.  */
#define EXTRACT_WORDS(ix0,ix1,d)				\
do {								\
  ieee_double_shape_type ew_u;					\
  ew_u.value = (d);						\
  (ix0) = ew_u.parts.msw;					\
  (ix1) = ew_u.parts.lsw;					\
} while (0)

/* Set a double from two 32 bit ints.  */
#define INSERT_WORDS(d,ix0,ix1)					\
do {								\
  ieee_double_shape_type iw_u;					\
  iw_u.parts.msw = (ix0);					\
  iw_u.parts.lsw = (ix1);					\
  (d) = iw_u.value;						\
} while (0)

static const double huge = 1.0e300;

/*
 * ceil(x)
 * Return x rounded toward -inf to integral value
 * Method:
 *	Bit twiddling.
 * Exception:
 *	Inexact flag raised if x not equal to ceil(x).
 */
double ceil(double x)
{
	int32_t i0,i1,j0;
	uint32_t i,j;
	EXTRACT_WORDS(i0,i1,x);
	j0 = ((i0>>20)&0x7ff)-0x3ff;
	if(j0<20) {
	    if(j0<0) { 	/* raise inexact if x != 0 */
		if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */
		    if(i0<0) {i0=0x80000000;i1=0;} 
		    else if((i0|i1)!=0) { i0=0x3ff00000;i1=0;}
		}
	    } else {
		i = (0x000fffff)>>j0;
		if(((i0&i)|i1)==0) return x; /* x is integral */
		if(huge+x>0.0) {	/* raise inexact flag */
		    if(i0>0) i0 += (0x00100000)>>j0;
		    i0 &= (~i); i1=0;
		}
	    }
	} else if (j0>51) {
	    if(j0==0x400) return x+x;	/* inf or NaN */
	    else return x;		/* x is integral */
	} else {
	    i = ((uint32_t)(0xffffffff))>>(j0-20);
	    if((i1&i)==0) return x;	/* x is integral */
	    if(huge+x>0.0) { 		/* raise inexact flag */
		if(i0>0) {
		    if(j0==20) i0+=1; 
		    else {
			j = i1 + (1<<(52-j0));
			if(j<i1) i0+=1;	/* got a carry */
			i1 = j;
		    }
		}
		i1 &= (~i);
	    }
	}
	INSERT_WORDS(x,i0,i1);
	return x;
}

#endif