* MOTOROLA MICROPROCESSOR & MEMORY TECHNOLOGY GROUP
* M68000 Hi-Performance Microprocessor Division
* M68040 Software Package
*
* M68040 Software Package Copyright (c) 1993, 1994 Motorola Inc.
* All rights reserved.
*
* THE SOFTWARE is provided on an "AS IS" basis and without warranty.
* To the maximum extent permitted by applicable law,
* MOTOROLA DISCLAIMS ALL WARRANTIES WHETHER EXPRESS OR IMPLIED,
* INCLUDING IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A
* PARTICULAR PURPOSE and any warranty against infringement with
* regard to the SOFTWARE (INCLUDING ANY MODIFIED VERSIONS THEREOF)
* and any accompanying written materials.
*
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*
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* distribute the SOFTWARE so long as this entire notice is retained
* without alteration in any modified and/or redistributed versions,
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* under any patents or trademarks of Motorola, Inc.
*
* stanh.sa 3.1 12/10/90
*
* The entry point sTanh computes the hyperbolic tangent of
* an input argument; sTanhd does the same except for denormalized
* input.
*
* Input: Double-extended number X in location pointed to
* by address register a0.
*
* Output: The value tanh(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 stanh takes approximately 270 cycles.
*
* Algorithm:
*
* TANH
* 1. If |X| >= (5/2) log2 or |X| <= 2**(-40), go to 3.
*
* 2. (2**(-40) < |X| < (5/2) log2) Calculate tanh(X) by
* sgn := sign(X), y := 2|X|, z := expm1(Y), and
* tanh(X) = sgn*( z/(2+z) ).
* Exit.
*
* 3. (|X| <= 2**(-40) or |X| >= (5/2) log2). If |X| < 1,
* go to 7.
*
* 4. (|X| >= (5/2) log2) If |X| >= 50 log2, go to 6.
*
* 5. ((5/2) log2 <= |X| < 50 log2) Calculate tanh(X) by
* sgn := sign(X), y := 2|X|, z := exp(Y),
* tanh(X) = sgn - [ sgn*2/(1+z) ].
* Exit.
*
* 6. (|X| >= 50 log2) Tanh(X) = +-1 (round to nearest). Thus, we
* calculate Tanh(X) by
* sgn := sign(X), Tiny := 2**(-126),
* tanh(X) := sgn - sgn*Tiny.
* Exit.
*
* 7. (|X| < 2**(-40)). Tanh(X) = X. Exit.
*
STANH IDNT 2,1 Motorola 040 Floating Point Software Package
