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⟦e4fce8aa5⟧ Ada Source

    Length: 3072 (0xc00)
    Types: Ada Source
    Notes: 03_class, FILE, R1k_Segment, e3_tag, function Log, seg_0130e0, separate Generic_Elementary_Functions

Derivation

└─⟦8527c1e9b⟧ Bits:30000544 8mm tape, Rational 1000, Arrival backup of disks in PAM's R1000
    └─⟦5a81ac88f⟧ »Space Info Vol 1« 
        └─⟦this⟧ 

separate (Generic_Elementary_Functions)

function Log (X : Float_Type) return Float_Type is

-- On input, X is a floating-point value in Float_Type;
-- on output, the value of log(X) (natural log of X) is returned.

-- The bulk of the computations are performed by the procedure
-- KP_Log( Y, M, Z1, Z2 ) which returns log(Y) in M, Z1, and Z2
-- where
--               log(Y) = M * log2  +  Z1  +  Z2,
-- M of integer value, and Z1 only has at most 12 significant bits.


   Y, M, Z1, Z2, Result : Common_Float;

   Log2_Lead  : constant Common_Float := 16#0.B17#;
   Log2_Trail : constant Common_Float :=
      16#0.000217F7D1CF79ABC9E3B39803F2F6AF40#;

begin

   Y := Common_Float (X);

   if (Y = 0.0) then
      raise Constraint_Error;
   end if;

   if (Y < 0.0) then
      raise Argument_Error;
   end if;

-- Get values of M, Z1, and Z2 so that the natural log of X
-- can be calculated by log(X) = M*log(2) + Z1 + Z2

   Kp_Log (Y, M, Z1, Z2);

   if (M = 0.0) then
      Result := Z1 + Z2;
   else
      Result := M * Log2_Trail + Z2;
      Result := (M * Log2_Lead + Z1) + Result;
   end if;

   return (Float_Type (Result));

end Log;

    nblk1=2
    nid=0
    hdr6=4
        [0x00] rec0=25 rec1=00 rec2=01 rec3=024
        [0x01] rec0=0e rec1=00 rec2=02 rec3=000
    tail 0x2150db62282b1522e0fb5 0x42a00066462061e03