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/arch/m68k/fpsp040/ssinh.S

https://bitbucket.org/thekraven/iscream_thunderc-2.6.35
Assembly | 134 lines | 115 code | 19 blank | 0 comment | 2 complexity | 768ca7bf91a83156a327d02472fc0e31 MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
  1|
  2|	ssinh.sa 3.1 12/10/90
  3|
  4|       The entry point sSinh computes the hyperbolic sine of
  5|       an input argument; sSinhd does the same except for denormalized
  6|       input.
  7|
  8|       Input: Double-extended number X in location pointed to
  9|		by address register a0.
 10|
 11|       Output: The value sinh(X) returned in floating-point register Fp0.
 12|
 13|       Accuracy and Monotonicity: The returned result is within 3 ulps in
 14|               64 significant bit, i.e. within 0.5001 ulp to 53 bits if the
 15|               result is subsequently rounded to double precision. The
 16|               result is provably monotonic in double precision.
 17|
 18|       Speed: The program sSINH takes approximately 280 cycles.
 19|
 20|       Algorithm:
 21|
 22|       SINH
 23|       1. If |X| > 16380 log2, go to 3.
 24|
 25|       2. (|X| <= 16380 log2) Sinh(X) is obtained by the formulae
 26|               y = |X|, sgn = sign(X), and z = expm1(Y),
 27|               sinh(X) = sgn*(1/2)*( z + z/(1+z) ).
 28|          Exit.
 29|
 30|       3. If |X| > 16480 log2, go to 5.
 31|
 32|       4. (16380 log2 < |X| <= 16480 log2)
 33|               sinh(X) = sign(X) * exp(|X|)/2.
 34|          However, invoking exp(|X|) may cause premature overflow.
 35|          Thus, we calculate sinh(X) as follows:
 36|             Y       := |X|
 37|             sgn     := sign(X)
 38|             sgnFact := sgn * 2**(16380)
 39|             Y'      := Y - 16381 log2
 40|             sinh(X) := sgnFact * exp(Y').
 41|          Exit.
 42|
 43|       5. (|X| > 16480 log2) sinh(X) must overflow. Return
 44|          sign(X)*Huge*Huge to generate overflow and an infinity with
 45|          the appropriate sign. Huge is the largest finite number in
 46|          extended format. Exit.
 47|
 48
 49|		Copyright (C) Motorola, Inc. 1990
 50|			All Rights Reserved
 51|
 52|       For details on the license for this file, please see the
 53|       file, README, in this same directory.
 54
 55|SSINH	idnt	2,1 | Motorola 040 Floating Point Software Package
 56
 57	|section	8
 58
 59T1:	.long 0x40C62D38,0xD3D64634 | ... 16381 LOG2 LEAD
 60T2:	.long 0x3D6F90AE,0xB1E75CC7 | ... 16381 LOG2 TRAIL
 61
 62	|xref	t_frcinx
 63	|xref	t_ovfl
 64	|xref	t_extdnrm
 65	|xref	setox
 66	|xref	setoxm1
 67
 68	.global	ssinhd
 69ssinhd:
 70|--SINH(X) = X FOR DENORMALIZED X
 71
 72	bra	t_extdnrm
 73
 74	.global	ssinh
 75ssinh:
 76	fmovex	(%a0),%fp0	| ...LOAD INPUT
 77
 78	movel	(%a0),%d0
 79	movew	4(%a0),%d0
 80	movel	%d0,%a1		| save a copy of original (compacted) operand
 81	andl	#0x7FFFFFFF,%d0
 82	cmpl	#0x400CB167,%d0
 83	bgts	SINHBIG
 84
 85|--THIS IS THE USUAL CASE, |X| < 16380 LOG2
 86|--Y = |X|, Z = EXPM1(Y), SINH(X) = SIGN(X)*(1/2)*( Z + Z/(1+Z) )
 87
 88	fabsx	%fp0		| ...Y = |X|
 89
 90	moveml	%a1/%d1,-(%sp)
 91	fmovemx %fp0-%fp0,(%a0)
 92	clrl	%d1
 93	bsr	setoxm1		| ...FP0 IS Z = EXPM1(Y)
 94	fmovel	#0,%fpcr
 95	moveml	(%sp)+,%a1/%d1
 96
 97	fmovex	%fp0,%fp1
 98	fadds	#0x3F800000,%fp1	| ...1+Z
 99	fmovex	%fp0,-(%sp)
100	fdivx	%fp1,%fp0		| ...Z/(1+Z)
101	movel	%a1,%d0
102	andl	#0x80000000,%d0
103	orl	#0x3F000000,%d0
104	faddx	(%sp)+,%fp0
105	movel	%d0,-(%sp)
106
107	fmovel	%d1,%fpcr
108	fmuls	(%sp)+,%fp0	|last fp inst - possible exceptions set
109
110	bra	t_frcinx
111
112SINHBIG:
113	cmpl	#0x400CB2B3,%d0
114	bgt	t_ovfl
115	fabsx	%fp0
116	fsubd	T1(%pc),%fp0	| ...(|X|-16381LOG2_LEAD)
117	movel	#0,-(%sp)
118	movel	#0x80000000,-(%sp)
119	movel	%a1,%d0
120	andl	#0x80000000,%d0
121	orl	#0x7FFB0000,%d0
122	movel	%d0,-(%sp)	| ...EXTENDED FMT
123	fsubd	T2(%pc),%fp0	| ...|X| - 16381 LOG2, ACCURATE
124
125	movel	%d1,-(%sp)
126	clrl	%d1
127	fmovemx %fp0-%fp0,(%a0)
128	bsr	setox
129	fmovel	(%sp)+,%fpcr
130
131	fmulx	(%sp)+,%fp0	|possible exception
132	bra	t_frcinx
133
134	|end