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Diffstat (limited to 'arch/m68k/fpsp040/satanh.S')
-rw-r--r-- | arch/m68k/fpsp040/satanh.S | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/arch/m68k/fpsp040/satanh.S b/arch/m68k/fpsp040/satanh.S new file mode 100644 index 000000000000..20f07810bcda --- /dev/null +++ b/arch/m68k/fpsp040/satanh.S @@ -0,0 +1,104 @@ +| +| satanh.sa 3.3 12/19/90 +| +| The entry point satanh computes the inverse +| hyperbolic tangent of +| an input argument; satanhd does the same except for denormalized +| input. +| +| Input: Double-extended number X in location pointed to +| by address register a0. +| +| Output: The value arctanh(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 satanh takes approximately 270 cycles. +| +| Algorithm: +| +| ATANH +| 1. If |X| >= 1, go to 3. +| +| 2. (|X| < 1) Calculate atanh(X) by +| sgn := sign(X) +| y := |X| +| z := 2y/(1-y) +| atanh(X) := sgn * (1/2) * logp1(z) +| Exit. +| +| 3. If |X| > 1, go to 5. +| +| 4. (|X| = 1) Generate infinity with an appropriate sign and +| divide-by-zero by +| sgn := sign(X) +| atan(X) := sgn / (+0). +| Exit. +| +| 5. (|X| > 1) Generate an invalid operation by 0 * infinity. +| 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 +| + +| Copyright (C) Motorola, Inc. 1990 +| All Rights Reserved +| +| THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA +| The copyright notice above does not evidence any +| actual or intended publication of such source code. + +|satanh idnt 2,1 | Motorola 040 Floating Point Software Package + + |section 8 + + |xref t_dz + |xref t_operr + |xref t_frcinx + |xref t_extdnrm + |xref slognp1 + + .global satanhd +satanhd: +|--ATANH(X) = X FOR DENORMALIZED X + + bra t_extdnrm + + .global satanh +satanh: + movel (%a0),%d0 + movew 4(%a0),%d0 + andil #0x7FFFFFFF,%d0 + cmpil #0x3FFF8000,%d0 + bges ATANHBIG + +|--THIS IS THE USUAL CASE, |X| < 1 +|--Y = |X|, Z = 2Y/(1-Y), ATANH(X) = SIGN(X) * (1/2) * LOG1P(Z). + + fabsx (%a0),%fp0 | ...Y = |X| + fmovex %fp0,%fp1 + fnegx %fp1 | ...-Y + faddx %fp0,%fp0 | ...2Y + fadds #0x3F800000,%fp1 | ...1-Y + fdivx %fp1,%fp0 | ...2Y/(1-Y) + movel (%a0),%d0 + andil #0x80000000,%d0 + oril #0x3F000000,%d0 | ...SIGN(X)*HALF + movel %d0,-(%sp) + + fmovemx %fp0-%fp0,(%a0) | ...overwrite input + movel %d1,-(%sp) + clrl %d1 + bsr slognp1 | ...LOG1P(Z) + fmovel (%sp)+,%fpcr + fmuls (%sp)+,%fp0 + bra t_frcinx + +ATANHBIG: + fabsx (%a0),%fp0 | ...|X| + fcmps #0x3F800000,%fp0 + fbgt t_operr + bra t_dz + + |end |