Re: Compute a Sin(X) and Cos(X) pair, FSINCOS, inlining

[Jerry van Dijk <jvandyk@attglobal.net>]

Gautier Write-only <gautier@somewhere.nil> writes:

> # Sorry, the original article already scrolled off my system.
> 
> Nice... (what system! even with on a VT220 I could scroll up news ;-)

Nah. I just hooked my VT220 clone to the serial port of my laptop, but
it didn't help... :-)

BTW, I always preferred the TeleVideo 970.

> BTW, what is the variant for Long_Float ?

Here is a full example of both:

------------------------------------------------------------------------------
with Ada.Text_IO;                       use Ada.Text_IO;
with Ada.Numerics;                      use Ada.Numerics;
with System.Machine_Code;               use System.Machine_Code;

with Ada.Numerics.Generic_Elementary_Functions;

procedure Check is

   package Float_Funcs is new
     Ada.Numerics.Generic_Elementary_Functions (Float);
   use Float_Funcs;

   package Long_Float_Funcs is new
     Ada.Numerics.Generic_Elementary_Functions (Long_Float);
   use Long_Float_Funcs;

   procedure Sin_Cos (Angle : Float; Sin : out Float; Cos : out Float);
   procedure Sin_Cos
     (Angle : Long_Float; Sin : out Long_Float; Cos : out Long_Float);
   pragma Inline (Sin_Cos);

   procedure Sin_Cos (Angle : Float; Sin : out Float; Cos : out Float) is
      use ASCII;
   begin
      Asm (("fsincos"  & LF & HT &
            "fstp  %0" & LF & HT &
            "fst   %1"),
           Outputs => (Float'Asm_Output ("=m", Cos),
                      (Float'Asm_Output ("=m", Sin))),
           Inputs  => (Float'Asm_Input ("t", Angle)));
   end Sin_Cos;

   procedure Sin_Cos
     (Angle : Long_Float; Sin : out Long_Float; Cos : out Long_Float) is
      use ASCII;
   begin
      Asm (("fsincos"  & LF & HT &
            "fstpl  %0" & LF & HT &
            "fstl   %1"),
           Outputs => (Long_Float'Asm_Output ("=m", Cos),
                      (Long_Float'Asm_Output ("=m", Sin))),
           Inputs  => (Long_Float'Asm_Input ("t", Angle)));
   end Sin_Cos;

   package IO_Concats is
      function "&" (S : String; F : Float) return String;
      function "&" (S : String; F : Long_Float) return String;
   end IO_Concats;

   package body IO_Concats is

      function "&" (S : String; F : Float) return String is
      begin
         return S & Float'Image (F);
      end "&";

      function "&" (S : String; F : Long_Float) return String is
      begin
         return S & Long_Float'Image (F);
      end "&";

   end IO_Concats;

   use IO_Concats;

   Sin_Float, Cos_Float : Float;
   Float_Value : constant Float := 0.25 * Pi;

   Sin_Long_Float, Cos_Long_Float : Long_Float;
   Long_Float_Value : constant Long_Float := 0.25 * Pi;

begin

   Sin_Float := Sin (Float_Value);
   Cos_Float := Cos (Float_Value);
   Put_Line ("Sin_Float:" & Sin_Float & ", Cos_Float:" & Cos_Float);

   Sin_Cos (Float_Value, Sin_Float, Cos_Float);
   Put_Line ("Sin_Float:" & Sin_Float & ", Cos_Float:" & Cos_Float);

   Sin_Long_Float := Sin (Long_Float_Value);
   Cos_Long_Float := Cos (Long_Float_Value);
   Put_Line
     ("Sin_LFloat:" & Sin_Long_Float & ", Cos_LFloat:" & Cos_Long_Float);

   Sin_Cos (Long_Float_Value, Sin_Long_Float, Cos_Long_Float);
   Put_Line
     ("Sin_LFloat:" & Sin_Long_Float & ", Cos_LFloat:" & Cos_Long_Float);

end Check;
-------------------------------------------------------------------------------

> In any case, it would be nice to have a compiler producing FSINCOS - e.g.
> for those users not familiar with machine code.

Yes. Have you checked gcc 3.3 ? Probably the Fortran folks would like this
too.

-- 
--  Jerry van Dijk   | email: jvandyk@attglobal.net
--  Leiden, Holland  | web:   users.ncrvnet.nl/gmvdijk