DP Tool Club 8/CDASC08.ISO/NEWS/554/AVRIL/FNT8X8.PAS

Pascal/Delphi Source File | 1993-10-07 | 5KB | 167 lines

{─ Fido Pascal Conference ────────────────────────────────────────────── PASCAL ─
Msg  : 118 of 150
From : Sean Palmer                         1:104/123.0          08 Apr 93  15:40
To   : All
Subj : G:Fnt8x8 unit
────────────────────────────────────────────────────────────────────────────────}
{ Fnt8x8 unit  v1.0 }
{   03/28/93        }
{ various support routines for vga 8x8 text modes}
{ stuff for smooth text mousing and 16-color backgrounds}
{ Copyright (c) 1993 Sean L. Palmer }
{ Released to the Public Domain }

{ You may distribute this freely and incorporate it with no royalties. }
{ Please credit me if your program uses these routines! }
{ If you really like them or learn something neat from me then I'd }
{ appreciate a small ($1 to $5) donation. }
{ Or contact me if you need something programmed or like my work... }
{ I probably have the wierdest indenting style for pascal ever! 8)  }
{ And, by God my stuff is optimized!! }

{ Sean L. Palmer (aka Ghost)}
{ 2237 Lincoln St. }
{ Longmont, CO 80501 }
{ [phone] }
{ also on FIDO, or at [e-mail] }

unit fnt8x8;
interface

procedure init;
function rows:byte;
procedure drawMouse(x,y:word);
procedure eraseMouse;

implementation

function rows:byte;assembler;asm
 mov ax,$1130; xor dx,dx; int $10;
 or dx,dx; jnz @S; mov dx,24; @S: {cga/mda don't have this fn}
 inc dx; mov al,dl;
 end;

type tChar=array[0..7]of byte;
const mouseBase=220;     {spot in charset mouse cursor uses}

{method to update chars was taken from a FIDO echo}
{only works on VGA as far as I know}

procedure accessChrMem;Inline(
  $FA/                   {cli}
  $BA/$C4/$03/           {mov dx,$3C4}
  $B8/$02/$04/           {mov ax,$0402}
  $EF/                   {out dx,ax}
  $B8/$04/$07/           {mov ax,$0704}
  $EF/                   {out dx,ax}
  $80/$C2/$0A/           {add dl,10}
  $B8/$04/$02/           {mov ax,$0204}
  $EF/                   {out dx,ax}
  $B8/$05/$00/           {mov ax,$0005}
  $EF/                   {out dx,ax}
  $B8/$06/$00/           {mov ax,$0006}
  $EF);                  {out dx,ax}

procedure accessVidMem;Inline(
  $BA/$C4/$03/           {mov dx,$3C4}
  $B8/$02/$03/           {mov ax,$0302}
  $EF/                   {out dx,ax}
  $B8/$04/$03/           {mov ax,$0304}
  $EF/                   {out dx,ax}
  $80/$C2/$0A/           {add dl,10}
  $B8/$04/$00/           {mov ax,$0004}
  $EF/                   {out dx,ax}
  $B8/$05/$10/           {mov ax,$1005}
  $EF/                   {out dx,ax}
  $B8/$06/$0E/           {mov ax,$0E06}
  $EF/                   {out dx,ax}
  $FB);                  {sti}

procedure SetChar(c:char;var data:tChar);begin
 accessChrMem; Move(data,mem[$A000:byte(c)*32],8); accessVidMem;
 end;

procedure getChar(c:char;var data:tChar);begin
 accessChrMem; Move(mem[$A000:byte(c)*32],data,8); accessVidMem;
 end;

const cursorData:tChar=($C0,$E0,$F0,$F8,$FC,$FE,$E0,$C0);

var
 oldChars:array[0..3]of byte;
 oldAdr:word;

procedure eraseMouse;var i:byte;a:word;begin
 asm cli; end;
 a:=oldAdr;
 for i:=0 to 3 do begin
  mem[$B800:a+i*2]:=oldchars[i];
  if i=1 then inc(a,160-4);
  end;
 asm sti;end;
 end;

procedure copyChar(s,d:char);var i:tChar;begin
 getchar(s,i);
 setChar(d,i);
 end;

procedure drawMouse(x,y:word);
var xl,yl,xr:byte;a:word;i:byte; pc,pd:^byte;
begin
 xl:=x and 7; yl:=y and 7; xr:=8-xl; x:=x shr 3; y:=y shr 3;
 a:=y*160+x*2; oldAdr:=a;
 for i:=0 to 3 do begin
  oldchars[i]:=mem[$B800:a+i*2];
  copychar(char(oldChars[i]),char(mouseBase+i));
  mem[$B800:a+i*2]:=mouseBase+i;
  if i=1 then inc(a,160-4);
  end;
 pc:=ptr($A000,mouseBase*32+yl);
 pd:=@cursorData;
 accessChrMem;
 for i:=0 to 7 do begin
  pc^:=pc^ or (pd^ shr xl); inc(word(pc),32);
  pc^:=pc^ or (pd^ shl xr); dec(word(pc),31);
  inc(word(pd));
  inc(yl); if yl=8 then inc(word(pc),56);  {handle wrap to next row}
  end;
 accessVidMem;
 end;

procedure init;assembler;asm
 mov ax,$1202; mov bl,$30; int $10; {select 400 scan lines}
 mov ax,3; int $10; {text mode}
 mov bl,0;mov ax,$1003; int $10;  {no blinking, enable 16 colors for
background}  mov ax,$1112; mov bl,0; int $10; {load 8x8 character set}
 end;

var oldmode:byte;
function vgaPresent:boolean;assembler;asm
 mov ah,$F; int $10; mov oldMode,al;  {save old Gr mode}
 mov ax,$1A00; int $10;    {check for VGA/MCGA}
 cmp al,$1A; jne @ERR;     {no VGA Bios}
 cmp bl,7; jb @ERR;        {is VGA or better?}
 cmp bl,$FF; jnz @OK;
@ERR: xor al,al; jmp @EXIT;
@OK: mov al,1;
@EXIT:
 end;

var exitSave:pointer;

procedure done;far;begin;
 exitProc:=exitSave;
 asm mov al,oldmode; xor ah,ah; int $10;end;
 end;

procedure blinkOn;assembler;asm mov bl,1;mov ax,$1003; int $10;end;

begin
 if vgaPresent then begin
  init;
  exitSave:=exitProc;exitProc:=@done;
  end
 else begin writeln('Need VGA.'); halt(1);end;
 end.