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Diffstat (limited to 'arch/m68k/fpsp040/scosh.S')
-rw-r--r-- | arch/m68k/fpsp040/scosh.S | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/arch/m68k/fpsp040/scosh.S b/arch/m68k/fpsp040/scosh.S new file mode 100644 index 000000000..07d3a4d7c --- /dev/null +++ b/arch/m68k/fpsp040/scosh.S @@ -0,0 +1,131 @@ +| +| 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 +| +| For details on the license for this file, please see the +| file, README, in this same directory. + +|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 |