/* RealImplSupport.c
	Copyright Ó 1988, 1990 by Xerox Corporation.  All rights reserved.
	Michael Plass, March 2, 1988 3:39:45 pm PST
	Bryan Lyles October 18, 1988 3:00:40 pm PDT
	Russ Atkinson, December 20, 1990 1:46:43 pm PST
	*/
		
/* must be compiled with -fsingle */

/* RealImplSupport.c provides the hooks into c floating-point support that are required by Basics.mesa and RealImpl.mesa */

#include <math.h>
	
typedef int REAL32;
typedef unsigned word, *ptr;

REAL32 XR_REAL32_from_double();
double XR_double_from_REAL32();

REAL32 XR_REAL32_from_double(d) double d; {
	float f = d;
	return (*((REAL32*) &f));
	}

double XR_double_from_REAL32(r) REAL32 r; {
	return (*((float*) &r));
	}

extern int XR_REAL32_Fix(r) REAL32 r; {
	int i;
	i = (int) (*(float *)(&r));
	return(i);
	}

extern int XR_REAL32_Round(r) REAL32 r; {
	/* this is a relatively expensive, but correct, round to nearest */
	word w = r;
	word absw = (w << 1) >> 1; /* quick and cheap hack for absolute value */
	float f = (*(float *)(&absw));
	float h = 0.5;
	int rnd = f+h;  /* round towards nearest (roughly) */
	float rf = rnd;
	float df = rf - f;
	if (df == h) if ((rnd & 1) == 1) rnd = rnd - 1;
	if (w != absw) rnd = -rnd;
	return (rnd);
	}

extern int XR_REAL32_Ceiling(r) REAL32 r; {
	int temp;
	float foo = (*(float *) (&r));
	temp = (int) foo;
	if (r <= 0) return (temp);
	if (temp == foo) return (temp);
	return (temp+1);
	}
	
extern int XR_REAL32_Floor(r) REAL32 r; {
	int temp;
	float foo = (*(float *) (&r));
	temp = (int) foo;
	if (r >= 0) return (temp);
	if (temp == foo) return (temp);
	return (temp - 1);
	}

extern int XR_RealCompare(x, y) REAL32 x, y; {
	/* ret: 0 --> x < y, 1 --> x = y, 2 --> x > y */
	int temp;
	float xf = (*(float *) (&x));
	float yf = (*(float *) (&y));
	if (xf < yf) return (0);
	if (xf > yf) return (2);
	return (1);
	}