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1da177e4c   Linus Torvalds   Linux-2.6.12-rc2 
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  |
  |	sasin.sa 3.3 12/19/90
  |
  |	Description: The entry point sAsin computes the inverse sine of
  |		an input argument; sAsind does the same except for denormalized
  |		input.
  |
  |	Input: Double-extended number X in location pointed to
  |		by address register a0.
  |
  |	Output: The value arcsin(X) returned in floating-point register Fp0.
  |
  |	Accuracy and Monotonicity: The returned result is within 3 ulps in
  |		64 significant bit, i.e. within 0.5001 ulp to 53 bits if the
  |		result is subsequently rounded to double precision. The
  |		result is provably monotonic in double precision.
  |
  |	Speed: The program sASIN takes approximately 310 cycles.
  |
  |	Algorithm:
  |
  |	ASIN
  |	1. If |X| >= 1, go to 3.
  |
  |	2. (|X| < 1) Calculate asin(X) by
  |		z := sqrt( [1-X][1+X] )
  |		asin(X) = atan( x / z ).
  |		Exit.
  |
  |	3. If |X| > 1, go to 5.
  |
  |	4. (|X| = 1) sgn := sign(X), return asin(X) := sgn * Pi/2. Exit.
  |
  |	5. (|X| > 1) Generate an invalid operation by 0 * infinity.
  |		Exit.
  |
  
  |		Copyright (C) Motorola, Inc. 1990
  |			All Rights Reserved
  |
e00d82d07   Matt Waddel   [PATCH] Add wordi... 
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  |       For details on the license for this file, please see the
  |       file, README, in this same directory.
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2 
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  |SASIN	idnt	2,1 | Motorola 040 Floating Point Software Package
  
  	|section	8
  
  PIBY2:	.long 0x3FFF0000,0xC90FDAA2,0x2168C235,0x00000000
  
  	|xref	t_operr
  	|xref	t_frcinx
  	|xref	t_extdnrm
  	|xref	satan
  
  	.global	sasind
  sasind:
  |--ASIN(X) = X FOR DENORMALIZED X
  
  	bra		t_extdnrm
  
  	.global	sasin
  sasin:
  	fmovex		(%a0),%fp0	| ...LOAD INPUT
  
  	movel		(%a0),%d0
  	movew		4(%a0),%d0
  	andil		#0x7FFFFFFF,%d0
  	cmpil		#0x3FFF8000,%d0
  	bges		asinbig
  
  |--THIS IS THE USUAL CASE, |X| < 1
  |--ASIN(X) = ATAN( X / SQRT( (1-X)(1+X) ) )
  
  	fmoves		#0x3F800000,%fp1
  	fsubx		%fp0,%fp1		| ...1-X
  	fmovemx	%fp2-%fp2,-(%a7)
  	fmoves		#0x3F800000,%fp2
  	faddx		%fp0,%fp2		| ...1+X
  	fmulx		%fp2,%fp1		| ...(1+X)(1-X)
  	fmovemx	(%a7)+,%fp2-%fp2
  	fsqrtx		%fp1		| ...SQRT([1-X][1+X])
  	fdivx		%fp1,%fp0		| ...X/SQRT([1-X][1+X])
  	fmovemx	%fp0-%fp0,(%a0)
  	bsr		satan
  	bra		t_frcinx
  
  asinbig:
  	fabsx		%fp0	 | ...|X|
  	fcmps		#0x3F800000,%fp0
  	fbgt		t_operr		|cause an operr exception
  
  |--|X| = 1, ASIN(X) = +- PI/2.
  
  	fmovex		PIBY2,%fp0
  	movel		(%a0),%d0
  	andil		#0x80000000,%d0	| ...SIGN BIT OF X
  	oril		#0x3F800000,%d0	| ...+-1 IN SGL FORMAT
  	movel		%d0,-(%sp)	| ...push SIGN(X) IN SGL-FMT
  	fmovel		%d1,%FPCR
  	fmuls		(%sp)+,%fp0
  	bra		t_frcinx
  
  	|end