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* Changed signature of frexp() to match one in Math unit, so eventually a duplicate implementation in Math can be removed. Currently this frexp() remains private to unit System.

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git-svn-id: trunk@33173 -
This commit is contained in:
sergei 2016-03-06 00:43:54 +00:00
parent e88285a257
commit feeb50be4f
2 changed files with 9 additions and 12 deletions
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7
rtl/inc/cgenmath.inc
View File

@ -115,13 +115,10 @@
{$define SYSTEM_HAS_FREXP}
function c_frexp(x: double; out e: longint): double; cdecl; external 'c' name 'frexp';
function frexp(x:ValReal; out e:Integer ):ValReal; {$ifdef MATHINLINE}inline;{$endif}
var
l: longint;
procedure frexp(x:ValReal; out Mantissa: ValReal; out Exponent: longint); {$ifdef MATHINLINE}inline;{$endif}
begin
resetexcepts;
frexp := c_frexp(x,l);
e := l;
Mantissa := c_frexp(x,Exponent);
checkexcepts;
end;
{$endif not SYSTEM_HAS_FREXP}

14
rtl/inc/genmath.inc
View File

@ -369,25 +369,25 @@ type
{$ifndef SYSTEM_HAS_FREXP}
function frexp(x:Real; out e:Integer ):Real;
procedure frexp(X: Real; out Mantissa: Real; out Exponent: longint);
{* frexp() extracts the exponent from x. It returns an integer *}
{* power of two to expnt and the significand between 0.5 and 1 *}
{* to y. Thus x = y * 2**expn. *}
begin
e :=0;
exponent:=0;
if (abs(x)<0.5) then
While (abs(x)<0.5) do
begin
x := x*2;
Dec(e);
Dec(exponent);
end
else
While (abs(x)>1) do
begin
x := x/2;
Inc(e);
Inc(exponent);
end;
frexp := x;
Mantissa := x;
end;
{$endif not SYSTEM_HAS_FREXP}
@ -1004,7 +1004,7 @@ type
{ a rough value for the square root. Then Heron's iteration }
{ is used three times to converge to an accurate value. }
{*****************************************************************}
var e : Integer;
var e : Longint;
w,z : Real;
begin
if( d <= 0.0 ) then
@ -1018,7 +1018,7 @@ type
begin
w := d;
{ separate exponent and significand }
z := frexp( d, e );
frexp( d, z, e );
{ approximate square root of number between 0.5 and 1 }
{ relative error of approximation = 7.47e-3 }