/*
THE COMPUTER CODE CONTAINED HEREIN IS THE SOLE PROPERTY OF PARALLAX
SOFTWARE CORPORATION ("PARALLAX").  PARALLAX, IN DISTRIBUTING THE CODE TO
END-USERS, AND SUBJECT TO ALL OF THE TERMS AND CONDITIONS HEREIN, GRANTS A
ROYALTY-FREE, PERPETUAL LICENSE TO SUCH END-USERS FOR USE BY SUCH END-USERS
IN USING, DISPLAYING,  AND CREATING DERIVATIVE WORKS THEREOF, SO LONG AS
SUCH USE, DISPLAY OR CREATION IS FOR NON-COMMERCIAL, ROYALTY OR REVENUE
FREE PURPOSES.  IN NO EVENT SHALL THE END-USER USE THE COMPUTER CODE
CONTAINED HEREIN FOR REVENUE-BEARING PURPOSES.  THE END-USER UNDERSTANDS
AND AGREES TO THE TERMS HEREIN AND ACCEPTS THE SAME BY USE OF THIS FILE.  
COPYRIGHT 1993-1998 PARALLAX SOFTWARE CORPORATION.  ALL RIGHTS RESERVED.
*/
/*
 * $Source: Smoke:miner:source:fix::RCS:fix.h $
 * $Revision: 1.2 $
 * $Author: allender $
 * $Date: 1995/08/31 15:44:01 $
 *
 * FIX.H - prototypes and macros for fixed-point functions
 *
 * Copyright (c) 1993  Matt Toschlog & Mike Kulas
 *
 * $Log: fix.h $
 * Revision 1.2  1995/08/31  15:44:01  allender
 * *** empty log message ***
 *
 * Revision 1.1  1995/04/17  11:37:59  allender
 * Initial revision
 *
 *
 * --- PC RCS Info ---
 * Revision 1.13  1994/12/06  13:52:34  matt
 * Added f2ir(), which is fix-to-int with rounding
 * 
 * Revision 1.12  1994/05/18  21:45:16  matt
 * Added comments
 * 
 * Revision 1.11  1994/01/19  23:12:02  matt
 * Made fix_atan2() left-handed, like our coordinate system
 * 
 * Revision 1.10  1993/10/20  01:09:00  matt
 * Add fix_asin(), improved fix_atan2()
 * 
 * Revision 1.9  1993/10/19  23:53:46  matt
 * Added fix_atan2()
 * 
 * Revision 1.8  1993/10/19  22:22:40  matt
 * Added fix_acos()
 * 
 * Revision 1.7  1993/09/17  11:37:01  mike
 * Add capitalized versions of "some handy constants", eg:
 * #define F1_0 f1_0
 * 
 * Revision 1.6  1993/08/24  13:00:48  matt
 * Adopted new standard, and made assembly-callable routines not trash any regs
 * 
 * Revision 1.5  1993/08/12  13:12:45  matt
 * Changed fixmul() to use SHRD instead of shl,shr,or
 * 
 * Revision 1.4  1993/08/04  19:57:18  matt
 * Added parens in fix/float conversion macros
 * 
 * Revision 1.3  1993/08/04  11:41:45  matt
 * Fixed bogus constants
 * 
 * Revision 1.2  1993/08/04  09:30:11  matt
 * Added more constants
 * 
 * Revision 1.1  1993/08/03  17:45:53  matt
 * Initial revision
 * 
 *
 */

#ifndef _FIX_H
#define _FIX_H

//#define USE_INLINE 1

#include "dtypes.h"

typedef long fix;				//16 bits int, 16 bits frac
typedef short fixang;		//angles

typedef struct quad {
	ulong low;
	long high;
} quad;

//Convert an int to a fix
#define i2f(i) ((i)<<16)

//Get the int part of a fix
#define f2i(f) ((f)>>16)

//Get the int part of a fix, with rounding
#define f2ir(f) (((f)+f0_5)>>16)

//Convert fix to float and float to fix
#define f2fl(f) (((float) (f)) / 65536.0)
#define fl2f(f) ((fix) ((f) * 65536))

//Some handy constants
#define f0_0	0
#define f1_0	0x10000
#define f2_0	0x20000
#define f3_0	0x30000
#define f10_0	0xa0000

#define f0_5 0x8000
#define f0_1 0x199a

#define F0_0	f0_0
#define F1_0	f1_0
#define F2_0	f2_0
#define F3_0	f3_0
#define F10_0	f10_0

#define F0_5 	f0_5
#define F0_1 	f0_1

//multiply two fixes, return a fix
fix fixmul(fix a,fix b);

//divide two fixes, return a fix
#ifdef __powerc
fix fixdiv(fix a,fix b);
//#define fixdiv(a,b) (fix)(((double)a * 65536.0) / (double)b)
#else
fix fixdiv(fix a,fix b);
#endif

//multiply two fixes, then divide by a third, return a fix
#ifdef __powerc
fix fixmuldiv(fix a,fix b,fix c);
//#define fixmuldiv(a,b,c) (fix)(((double)a * (double)b)/(double)c)
#else
fix fixmuldiv(fix a,fix b,fix c);
#endif

//multiply two fixes, and add 64-bit product to a quad
void fixmulaccum(quad *q,fix a,fix b);

//extract a fix from a quad product
fix fixquadadjust(quad *q);

//divide a quad by a long
long fixdivquadlong(ulong qlow,ulong qhigh,ulong d);

//negate a quad
void fixquadnegate(quad *q);

#if defined(__WATCOMC__) && defined(USE_INLINE)

#pragma aux fixmul parm [eax] [edx] = \
	"imul	edx"				\
	"shrd	eax,edx,16";

#pragma aux fixdiv parm [eax] [ebx] modify exact [eax edx] = \
	"mov	edx,eax"	\
	"sar	edx,16"	\
	"shl	eax,16"	\
	"idiv	ebx";

#pragma aux fixmuldiv parm [eax] [edx] [ebx] modify exact [eax edx] = \
	"imul	edx"			\
	"idiv ebx";

#pragma aux fixmulaccum parm [esi] [eax] [edx] modify exact [eax edx] = \
	"imul	edx"			\
	"add  [esi],eax"	\
	"adc	4[esi],edx";

#pragma aux fixquadadjust parm [esi] modify exact [eax edx] = \
	"mov  eax,[esi]"		\
	"mov  edx,4[esi]"		\
	"shrd	eax,edx,16";

#pragma aux fixquadnegate parm [eax] modifiy exact [] = \
	"neg	[eax]"			\
	"not	4[eax]"			\
	"sbb	4[eax],-1";

#pragma aux fixdivquadlong parm [eax] [edx] [ebx] modifiy exact [eax edx] = \
	"idiv	ebx";

#endif

//computes the square root of a long, returning a short
ushort long_sqrt(long a);

//computes the square root of a quad, returning a long
ulong quad_sqrt(long low,long high);

//computes the square root of a fix, returning a fix
fix fix_sqrt(fix a);

//compute sine and cosine of an angle, filling in the variables
//either of the pointers can be NULL
void fix_sincos(fix a,fix *s,fix *c);		//with interpolation
void fix_fastsincos(fix a,fix *s,fix *c);	//no interpolation

//compute inverse sine & cosine
fixang fix_asin(fix v); 
fixang fix_acos(fix v); 

//given cos & sin of an angle, return that angle.
//parms need not be normalized, that is, the ratio of the parms cos/sin must
//equal the ratio of the actual cos & sin for the result angle, but the parms 
//need not be the actual cos & sin.  
//NOTE: this is different from the standard C atan2, since it is left-handed.
fixang fix_atan2(fix cos,fix sin); 

//for passed value a, returns 1/sqrt(a) 
fix fix_isqrt( fix a );


#endif