CubicDesign wrote:
> I need a fast function that compares three numbers and returns the
> biggest.
> Do you know an ASM library that can do such a calculation?
>
> I downloaded a library called 'Math387' which implements such a function
> but for two numbers, not for three.
The name of that unit suggests it's a unit written for the Intel 80387
math coprocessor; is it really that old?
> The person who made the library pretends that it is made in ASM but
> actually, it has the same speed as Borland's Max function.
Being written in assembler and performing the same as the function in the
Math unit aren't mutually exclusive things.
> I need this function in a loop that is executed 100,000,000 times. By
> itself, it takes 2.1 seconds.
For one hundred million things, that seems pretty fast already. How fast
do you want it go instead?
> *Borland Max function:*
>
> function Max(const A, B: Integer): Integer;
> begin
> if A > B then
> Result := A
> else
> Result := B;
> end;
Yep. There's not really much more you can do with that.
> *My function (for 3 numbers):*
>
> function Find_Max(const v1,v2,v3: integer): Integer;
> begin
> Result:= v1;
> if (v2 > Result) then Result:= v2;
> if (v3 > Result) then Result:= v3;
> end;
That executes two comparisons and a maximum of three assignments.
function Max(const A, B, C: Integer): Integer;
begin
if A > B then
if A > C then
Result := A
else
Result := C
else
if B > C then
Result := B
else
Result := C;
end;
That executes two comparisons and a maximum of one assignment.
--
Rob
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