``````{
MIKE BURNS

> does someone have a circle routine for the 320x200x256 mode. I need one
> using the assembler...  (FAST) ( or isn't that possible) I doesn't need to
> be very perfect, if it has the shape of a circle, I'm satisfied.
}

PROCEDURE SWAP(VAR A, B : Integer);
Var
X : Integer;
Begin
X := A;
A := B;
B := X;
End;

Var
SCR : Array [0..199, 0..319] of Byte Absolute \$A000 : \$0000;

PROCEDURE Circle(X, Y, Radius : Word; Color: Byte);
VAR
a, af, b, bf,
target, r2   : Integer;
Begin
Target := 0;
A  := Radius;
B  := 0;
R2 := Sqr(Radius);

While a >= B DO
Begin
b:= Round(Sqrt(R2 - Sqr(A)));
Swap(Target, B);
While B < Target Do
Begin
Af := (120 * a) Div 100;
Bf := (120 * b) Div 100;
SCR[x + af, y + b] := color;
SCR[x + bf, y + a] := color;
SCR[x - af, y + b] := color;
SCR[x - bf, y + a] := color;
SCR[x - af, y - b] := color;
SCR[x - bf, y - a] := color;
SCR[x + af, y - b] := color;
SCR[x + bf, y - a] := color;
B := B + 1;
End;
A := A - 1;
End;
End;

begin
Asm
Mov ax, \$13
Int \$10;
end;

Circle(50, 50, 40, \$32);
Readln;

Asm
Mov ax, \$03
Int \$10;
end;
end.

``````