patch-1.3.94 linux/arch/m68k/fpsp040/scosh.S

• Lines: 133
• Date: Sat Feb 24 22:58:43 1996
• Orig file: v1.3.93/linux/arch/m68k/fpsp040/scosh.S
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.93/linux/arch/m68k/fpsp040/scosh.S linux/arch/m68k/fpsp040/scosh.S
@@ -0,0 +1,132 @@
+|
+|	scosh.sa 3.1 12/10/90
+|
+|	The entry point sCosh computes the hyperbolic cosine of
+|	an input argument; sCoshd does the same except for denormalized
+|	input.
+|
+|	Input: Double-extended number X in location pointed to
+|		by address register a0.
+|
+|	Output: The value cosh(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 sCOSH takes approximately 250 cycles.
+|
+|	Algorithm:
+|
+|	COSH
+|	1. If |X| > 16380 log2, go to 3.
+|
+|	2. (|X| <= 16380 log2) Cosh(X) is obtained by the formulae
+|		y = |X|, z = exp(Y), and
+|		cosh(X) = (1/2)*( z + 1/z ).
+|		Exit.
+|
+|	3. (|X| > 16380 log2). If |X| > 16480 log2, go to 5.
+|
+|	4. (16380 log2 < |X| <= 16480 log2)
+|		cosh(X) = sign(X) * exp(|X|)/2.
+|		However, invoking exp(|X|) may cause premature overflow.
+|		Thus, we calculate sinh(X) as follows:
+|		Y	:= |X|
+|		Fact	:=	2**(16380)
+|		Y'	:= Y - 16381 log2
+|		cosh(X) := Fact * exp(Y').
+|		Exit.
+|
+|	5. (|X| > 16480 log2) sinh(X) must overflow. Return
+|		Huge*Huge to generate overflow and an infinity with
+|		the appropriate sign. Huge is the largest finite number in
+|		extended format. Exit.
+|
+|
+
+|		Copyright (C) Motorola, Inc. 1990
+|			All Rights Reserved
+|
+|	THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA 
+|	The copyright notice above does not evidence any  
+|	actual or intended publication of such source code.
+
+|SCOSH	idnt	2,1 | Motorola 040 Floating Point Software Package
+
+	|section	8
+
+	|xref	t_ovfl
+	|xref	t_frcinx
+	|xref	setox
+
+T1:	.long 0x40C62D38,0xD3D64634 | ... 16381 LOG2 LEAD
+T2:	.long 0x3D6F90AE,0xB1E75CC7 | ... 16381 LOG2 TRAIL
+
+TWO16380: .long 0x7FFB0000,0x80000000,0x00000000,0x00000000
+
+	.global	scoshd
+scoshd:
+|--COSH(X) = 1 FOR DENORMALIZED X
+
+	fmoves		#0x3F800000,%fp0
+
+	fmovel		%d1,%FPCR
+	fadds		#0x00800000,%fp0
+	bra		t_frcinx
+
+	.global	scosh
+scosh:
+	fmovex		(%a0),%fp0	| ...LOAD INPUT
+
+	movel		(%a0),%d0
+	movew		4(%a0),%d0
+	andil		#0x7FFFFFFF,%d0
+	cmpil		#0x400CB167,%d0
+	bgts		COSHBIG
+
+|--THIS IS THE USUAL CASE, |X| < 16380 LOG2
+|--COSH(X) = (1/2) * ( EXP(X) + 1/EXP(X) )
+
+	fabsx		%fp0		| ...|X|
+
+	movel		%d1,-(%sp)
+	clrl		%d1
+	fmovemx	%fp0-%fp0,(%a0)	|pass parameter to setox
+	bsr		setox		| ...FP0 IS EXP(|X|)
+	fmuls		#0x3F000000,%fp0	| ...(1/2)EXP(|X|)
+	movel		(%sp)+,%d1
+
+	fmoves		#0x3E800000,%fp1	| ...(1/4)
+	fdivx		%fp0,%fp1	 	| ...1/(2 EXP(|X|))
+
+	fmovel		%d1,%FPCR
+	faddx		%fp1,%fp0
+
+	bra		t_frcinx
+
+COSHBIG:
+	cmpil		#0x400CB2B3,%d0
+	bgts		COSHHUGE
+
+	fabsx		%fp0
+	fsubd		T1(%pc),%fp0		| ...(|X|-16381LOG2_LEAD)
+	fsubd		T2(%pc),%fp0		| ...|X| - 16381 LOG2, ACCURATE
+
+	movel		%d1,-(%sp)
+	clrl		%d1
+	fmovemx	%fp0-%fp0,(%a0)
+	bsr		setox
+	fmovel		(%sp)+,%fpcr
+
+	fmulx		TWO16380(%pc),%fp0
+	bra		t_frcinx
+
+COSHHUGE:
+	fmovel		#0,%fpsr		|clr N bit if set by source
+	bclrb		#7,(%a0)		|always return positive value
+	fmovemx	(%a0),%fp0-%fp0
+	bra		t_ovfl
+
+	|end