;/***
;*triga.a - asin, acos, atan functions 
;*
;*	Copyright (c) 1991-1991, Microsoft Corporation.	All rights reserved.
;*
;*Purpose:
;*   Arc trig  functions to be used with M68K version
;*
;*Revision History:
;*   05-13-92  XY   MAC version
;*
;*******************************************************************************/

#include <traps.a>
#ifdef SANE
#include <sane.a>
#endif

	externW _errno

;double atan(double x)


cProc atan,PUBLIC
	parmQ x
	localW fpstat
	localV xlocalx,10
	localW xtestw
cBegin atan
#ifdef SANE
	pea fpstat
	move.w #FOPROCENTRY,-(a7)
	FP68K			;save current status & set default control
	pea x
	pea xlocalx
	move.w #FFDBL+FOZ2X,-(a7)
	FP68K			;convert to extended

	pea xlocalx
	move.w #FOATANX,-(a7)
	Elems68K		;atan x
	lea xlocalx,a1
	move.w (a1)+,d0		;load result for return
	move.l (a1)+,d1
	move.l (a1),a0

	pea fpstat
	move.w #FOPROCEXIT,-(a7)
	FP68K			;set result status & restore control

#else
      	fmove.l fpcr,d0

	fmove.d x, fp0
	ftst.x fp0              ;see if it is a valid number
	fmove.l fpsr, d1        ;get status word
	and.l #0x03007c00, d1  ;see if we get an exception
	cmp.l #0, d1
	bne domain_error_fpu

      	fmove.l #0,fpcr
      	fatan.d x,fp0
	jra to_end_fpu

domain_error_fpu:
	move.l #33, _errno
to_end_fpu:
      	fmove.l	d0,fpcr
#endif
cEnd atan

#ifndef SANE

;double asin(double x)


cProc asin,PUBLIC
	parmQ x
cBegin asin
      	fmove.l fpcr,d0

	fmove.d x, fp0
;	fmove.d #1, fp1
;	fcmp.d fp1, fp0
;	bgt domain_error_fpu2
;	fmove.d #-1, fp1
;	fcmp.d fp1, fp0
;	blt domain_error_fpu2

      	fmove.l #0,fpcr
      	fasin.d x,fp0
	jra to_end_fpu2

domain_error_fpu2:
	move.l #33, _errno
to_end_fpu2:
      	fmove.l	d0,fpcr
cEnd asin


;double acos(double x)


cProc acos,PUBLIC
	parmQ x
cBegin acos
      	fmove.l fpcr,d0

;	fmove.d x, fp0
;	fmove.d #1, fp1
; 	fcmp.d fp1, fp0
;	bgt domain_error_fpu3
;	fmove.d #-1, fp1
;	fcmp.d fp1, fp0
;	blt domain_error_fpu3

      	fmove.l #0,fpcr
      	facos.d x,fp0
	jra to_end_fpu3

domain_error_fpu3:
	move.l #33, _errno
to_end_fpu3:
      	fmove.l	d0,fpcr
cEnd acos

#endif