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author | Arnaud Charlet <charlet@gcc.gnu.org> | 2017-09-11 12:12:05 +0200 |
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committer | Arnaud Charlet <charlet@gcc.gnu.org> | 2017-09-11 12:12:05 +0200 |
commit | a0713cb6beb00ca850e7c20f287d32f1e1a14a49 (patch) | |
tree | c3c846308e8396ca48bd205ca87021e5afd9a0f0 /gcc/ada/libgnat/a-numaux__darwin.adb | |
parent | 6f77df7260f6f1ce89ecb2ee82d9f40447d813bc (diff) | |
download | gcc-a0713cb6beb00ca850e7c20f287d32f1e1a14a49.zip gcc-a0713cb6beb00ca850e7c20f287d32f1e1a14a49.tar.gz gcc-a0713cb6beb00ca850e7c20f287d32f1e1a14a49.tar.bz2 |
libgnat: Rename ?-[a-z]*-* into ?-[a-z]*__*
2017-09-11 Jerome Lambourg <lambourg@adacore.com>
* libgnat: Rename ?-[a-z]*-* into ?-[a-z]*__*
* gcc-interface/Makefile.in, gcc-interface/Make-lang.in: Take this
renaming into account.
From-SVN: r251968
Diffstat (limited to 'gcc/ada/libgnat/a-numaux__darwin.adb')
-rw-r--r-- | gcc/ada/libgnat/a-numaux__darwin.adb | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/gcc/ada/libgnat/a-numaux__darwin.adb b/gcc/ada/libgnat/a-numaux__darwin.adb new file mode 100644 index 0000000..88e9e7c --- /dev/null +++ b/gcc/ada/libgnat/a-numaux__darwin.adb @@ -0,0 +1,211 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT RUN-TIME COMPONENTS -- +-- -- +-- A D A . N U M E R I C S . A U X -- +-- -- +-- B o d y -- +-- (Apple OS X Version) -- +-- -- +-- Copyright (C) 1998-2017, Free Software Foundation, Inc. -- +-- -- +-- GNAT is free software; you can redistribute it and/or modify it under -- +-- terms of the GNU General Public License as published by the Free Soft- -- +-- ware Foundation; either version 3, or (at your option) any later ver- -- +-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- +-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- +-- or FITNESS FOR A PARTICULAR PURPOSE. -- +-- -- +-- As a special exception under Section 7 of GPL version 3, you are granted -- +-- additional permissions described in the GCC Runtime Library Exception, -- +-- version 3.1, as published by the Free Software Foundation. -- +-- -- +-- You should have received a copy of the GNU General Public License and -- +-- a copy of the GCC Runtime Library Exception along with this program; -- +-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- +-- <http://www.gnu.org/licenses/>. -- +-- -- +-- GNAT was originally developed by the GNAT team at New York University. -- +-- Extensive contributions were provided by Ada Core Technologies Inc. -- +-- -- +------------------------------------------------------------------------------ + +package body Ada.Numerics.Aux is + + ----------------------- + -- Local subprograms -- + ----------------------- + + function Is_Nan (X : Double) return Boolean; + -- Return True iff X is a IEEE NaN value + + procedure Reduce (X : in out Double; Q : out Natural); + -- Implement reduction of X by Pi/2. Q is the quadrant of the final + -- result in the range 0..3. The absolute value of X is at most Pi/4. + -- It is needed to avoid a loss of accuracy for sin near Pi and cos + -- near Pi/2 due to the use of an insufficiently precise value of Pi + -- in the range reduction. + + -- The following two functions implement Chebishev approximations + -- of the trigonometric functions in their reduced domain. + -- These approximations have been computed using Maple. + + function Sine_Approx (X : Double) return Double; + function Cosine_Approx (X : Double) return Double; + + pragma Inline (Reduce); + pragma Inline (Sine_Approx); + pragma Inline (Cosine_Approx); + + ------------------- + -- Cosine_Approx -- + ------------------- + + function Cosine_Approx (X : Double) return Double is + XX : constant Double := X * X; + begin + return (((((16#8.DC57FBD05F640#E-08 * XX + - 16#4.9F7D00BF25D80#E-06) * XX + + 16#1.A019F7FDEFCC2#E-04) * XX + - 16#5.B05B058F18B20#E-03) * XX + + 16#A.AAAAAAAA73FA8#E-02) * XX + - 16#7.FFFFFFFFFFDE4#E-01) * XX + - 16#3.655E64869ECCE#E-14 + 1.0; + end Cosine_Approx; + + ----------------- + -- Sine_Approx -- + ----------------- + + function Sine_Approx (X : Double) return Double is + XX : constant Double := X * X; + begin + return (((((16#A.EA2D4ABE41808#E-09 * XX + - 16#6.B974C10F9D078#E-07) * XX + + 16#2.E3BC673425B0E#E-05) * XX + - 16#D.00D00CCA7AF00#E-04) * XX + + 16#2.222222221B190#E-02) * XX + - 16#2.AAAAAAAAAAA44#E-01) * (XX * X) + X; + end Sine_Approx; + + ------------ + -- Is_Nan -- + ------------ + + function Is_Nan (X : Double) return Boolean is + begin + -- The IEEE NaN values are the only ones that do not equal themselves + + return X /= X; + end Is_Nan; + + ------------ + -- Reduce -- + ------------ + + procedure Reduce (X : in out Double; Q : out Natural) is + Half_Pi : constant := Pi / 2.0; + Two_Over_Pi : constant := 2.0 / Pi; + + HM : constant := Integer'Min (Double'Machine_Mantissa / 2, Natural'Size); + M : constant Double := 0.5 + 2.0**(1 - HM); -- Splitting constant + P1 : constant Double := Double'Leading_Part (Half_Pi, HM); + P2 : constant Double := Double'Leading_Part (Half_Pi - P1, HM); + P3 : constant Double := Double'Leading_Part (Half_Pi - P1 - P2, HM); + P4 : constant Double := Double'Leading_Part (Half_Pi - P1 - P2 - P3, HM); + P5 : constant Double := Double'Leading_Part (Half_Pi - P1 - P2 - P3 + - P4, HM); + P6 : constant Double := Double'Model (Half_Pi - P1 - P2 - P3 - P4 - P5); + K : Double; + R : Integer; + + begin + -- For X < 2.0**HM, all products below are computed exactly. + -- Due to cancellation effects all subtractions are exact as well. + -- As no double extended floating-point number has more than 75 + -- zeros after the binary point, the result will be the correctly + -- rounded result of X - K * (Pi / 2.0). + + K := X * Two_Over_Pi; + while abs K >= 2.0**HM loop + K := K * M - (K * M - K); + X := + (((((X - K * P1) - K * P2) - K * P3) - K * P4) - K * P5) - K * P6; + K := X * Two_Over_Pi; + end loop; + + -- If K is not a number (because X was not finite) raise exception + + if Is_Nan (K) then + raise Constraint_Error; + end if; + + -- Go through an integer temporary so as to use machine instructions + + R := Integer (Double'Rounding (K)); + Q := R mod 4; + K := Double (R); + X := (((((X - K * P1) - K * P2) - K * P3) - K * P4) - K * P5) - K * P6; + end Reduce; + + --------- + -- Cos -- + --------- + + function Cos (X : Double) return Double is + Reduced_X : Double := abs X; + Quadrant : Natural range 0 .. 3; + + begin + if Reduced_X > Pi / 4.0 then + Reduce (Reduced_X, Quadrant); + + case Quadrant is + when 0 => + return Cosine_Approx (Reduced_X); + + when 1 => + return Sine_Approx (-Reduced_X); + + when 2 => + return -Cosine_Approx (Reduced_X); + + when 3 => + return Sine_Approx (Reduced_X); + end case; + end if; + + return Cosine_Approx (Reduced_X); + end Cos; + + --------- + -- Sin -- + --------- + + function Sin (X : Double) return Double is + Reduced_X : Double := X; + Quadrant : Natural range 0 .. 3; + + begin + if abs X > Pi / 4.0 then + Reduce (Reduced_X, Quadrant); + + case Quadrant is + when 0 => + return Sine_Approx (Reduced_X); + + when 1 => + return Cosine_Approx (Reduced_X); + + when 2 => + return Sine_Approx (-Reduced_X); + + when 3 => + return -Cosine_Approx (Reduced_X); + end case; + end if; + + return Sine_Approx (Reduced_X); + end Sin; + +end Ada.Numerics.Aux; |