;
; fixedPt.sh
;
; Provides fixed point operations such as trignometry
;
; © 1994-1998 Straylight
;

;----- Licensing note -------------------------------------------------------
;
; This file is part of Straylight's Sapphire library.
;
; Sapphire 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 2, or (at your option)
; any later version.
;
; Sapphire 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 Sapphire.  If not, write to the Free Software Foundation,
; 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

;----- Overview -------------------------------------------------------------
;
; Functions provided:
;
;  fxp_atan
;  fxp_pol
;  fxp_sin
;  fxp_cos

		[	:LNOT::DEF:fixedPt__dfn
		GBLL	fixedPt__dfn

; --- fxp_atan ---
;
; On entry:	R0 == x, in 16.16 fixed point form
;
; On exit:	R0 == arctan x, in degrees, in 16.16 fixed point
;
; Use:		Calculates arctan x, hopefully fairly swiftly. The
;		accuracy of the result is open to doubt, although
;		it's usually good to about 3 significant figures.
;		It uses a small lookup table and linear interpolation
;		to calculate the result.

		IMPORT	fxp_atan

; --- fxp_pol ---
;
; On entry:	R0 == x coordinate
; 		R1 == y coordinate
;
; On exit:	R0 == angle in degrees, in 16.16 form
;
; Use:		Calculates the angle a vector makes with the +ve x axis.
;		The angle is given in degrees, rather than radians,
;		although this isn't really overly significant; it just
;		makes it slightly easier to work with, because it's
;		bigger.
;
;		This routine uses the arctan table and linear
;		interpolation, so it's fairly quick, but the accuracy
;		of its results is restricted to about 3 significant figures.

		IMPORT	fxp_pol

; --- fxp_sin ---
;
; On entry:	R0 == angle in degrees, in 16.16 form
;
; On exit:	R0 == sin of angle, in 16.16 form
;
; Use:		Calculates a sin of an angle with a degree of swiftness and
;		a lot less accuracy.

		IMPORT	fxp_sin

; --- fxp_cos ---
;
; On entry:	R0 == angle in degrees, in 16.16 form
;
; On exit:	R0 == cos of angle, in 16.16 form
;
; Use:		Calculates a cos of an angle with a degree of swiftness and
;		a lot less accuracy.

		IMPORT	fxp_cos

		]

;----- That's all, folks ----------------------------------------------------

		END