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; tinyfrac.asm

;

; teeny program displays the Mandelbrot set.

;

; written on Sun  03-26-1995  by Ed Beroset (Fidonet 1:3641/1.250)

;

; This program was based on a program by Frank Hommers, later optimized

; for size by Mikko Hyvarinen and posted in Fidonet's 80XXX echo.

;

; This new version has many new features and was based on my own

; optimization of Hyvarinen's version.  Some features:

;

; pan     using the arrow keys, one can navigate the fractal.

;

;               Home  Up  PgUp

;               Left      Right   correspond to 8 obvious directions

;               End   Dn  PgDn

;

; zoom    there are now ten levels of magnification available.  If the

;         program is assembled with FEATURES defined, the number

;         corresponding to the zoom level (0-9, zero is most zoomed in)

;         is displayed in the upper left hand corner of the screen just

;         before each new fractal is drawn.  The gray '+' key zooms out,

;         the gray '-' key zooms in.

;

; beep    the program will beep at the completion of each fractal

;         drawing or if the user attempts to zoom past either limit.

;

; mode    if the program is assembled with MODECHANGE defined, the

;         will change to the next video mode if the 'v' key is pressed.

;         This is handy because drawing fractals at high resolution can

;         be very timeconsuming.  The user can find an interesting spot

;         in a low res mode and then change to a high res mode to see it

;         more fully rendered.

;

; size    this whole project was started off as a size optimization

;         exercise, so there have been some rather ugly tradeoffs to

;         sacrifice speed for size.

;

; 8086    yes, it runs on an 8086 although only if you leave out either

;         the FEATURES option or the MODECHANGE option and it would be

;         slower and more painful than oral surgery.

;

; cost    there IS such a thing as a free lunch!  This code is hereby

;         released to the public domain by the author.

;

;

; to assemble & link:

;   TASM /m2 tinyfrac       (assemble using two pass mode if required)

;   TLINK /Tdc tinyfrac     (link Target platform is DOS, COM file)

;

;

PIXWIDTH    equ 511

PIXHEIGHT   equ 255

ZOOMLIMIT   equ  13       ; can change to up to 13 for extended zoom in

; feel free to experiment with the following constants:

DELTA       equ 200       ; the unit of pan movement in pixels

THRESHOLD   equ  7       ; must be in the range of (0,255)

STARTSCALE  equ  5        ; a number from 0 to ZOOMLIMIT, inclusive

CHAR_COLOR  equ 0fh       ; white on black background (for PRINTZOOM feature)

; ************************************************************

;

;   Menuet header

use32

                  org     0x0

                  db      'MENUET01'

                  dd      0x01

                  dd      START

                  dd      I_END

                  dd      0x62000

                  dd      0x1000

                  dd      0,0

include 'lang.inc'

include 'macros.inc'

STARTX  dd  200

STARTY  dd  120

scaleaddy dd 120

scaleaddx dd 200

START:

        call    draw_window

        call    draw_fractal

still:

        mov  eax,10

        int  0x40

        cmp  eax,1

        je   red

        cmp  eax,2

        je   key

        cmp  eax,3

        je   button

        jmp  still

      red:

        call draw_window

        call put_image

        jmp  still

      key:

        mov  eax,2

        int  0x40

        cmp  ah,'e'

        je   cycle

        cmp  ah,'r'

        je   cycle

        jmp  no_cycle

      cycle:

        call color_cycle

        jmp  still

      no_cycle:

        cmp  ah,'q'

        jne  no_in

        inc  byte [scale]

        mov  ebx,[STARTX]

        imul ebx,2

        sub  ebx,[scaleaddx]

        mov  [STARTX],ebx

        mov  ebx,[STARTY]

        imul ebx,2

        sub  ebx,[scaleaddy]

        mov  [STARTY],ebx

      no_in:

        cmp  ah,'w'

        jne  no_out

        dec  byte [scale]

        mov  ebx,[STARTX]

        add  ebx,[scaleaddx]

        shr  ebx,1

        mov  [STARTX],ebx

        mov  ebx,[STARTY]

        add  ebx,[scaleaddy]

        shr  ebx,1

        mov  [STARTY],ebx

      no_out:

        cmp  ah,130+48

        jne  no_up

        sub  [STARTY],100

      no_up:

        cmp  ah,129+48

        jne  no_down

        add  [STARTY],100

      no_down:

        cmp  ah,128+48

        jne  no_left

        sub  [STARTX],100

      no_left:

        cmp  ah,131+48

        jne  no_right

        add  [STARTX],100

      no_right:

        call draw_fractal

        jmp  still

      button:

        mov  eax,17

        int  0x40

        cmp  ah,1

        jne  no_close

        mov  eax,-1

        int  0x40

      no_close:

        cmp  ah,2

        jne  no_bgr

        mov  eax,15   ; bgr 512 x 256

        mov  ebx,1

        mov  ecx,512

        mov  edx,256

        int  0x40

        mov  eax,15

        mov  ebx,5

        mov  ecx,0x1000

        mov  edx,0

        mov  esi,512*3*256

        int  0x40

        mov  eax,15

        mov  ebx,3

        int  0x40

        jmp  still

      no_bgr:

        cmp  ah,3

        jb   no_color

        cmp  ah,5

        jg   no_color

        shr  eax,8

        sub  eax,3

        imul eax,8

        add  eax,8

        not  eax

        and  eax,11000b

;        sub  eax,8

        mov  [shlc],al

        call draw_fractal

        jmp  still

      no_color:

        jmp  still

color_cycle:

     pusha

     mov  ecx,0x08080808

     mov  esi,(256/8)*5

     cmp  ah,'e'

     je   f_out

     mov  ecx,-0x08080808

     mov  esi,(256/8)*5-1

   f_out:

   newcycle:

     mov  edi,0x1000

   newpix:

     mov  eax,[edi]

     add  eax,ecx

     mov  [edi],eax

     add  edi,4

     cmp  edi,0x1000+512*256*3

     jb   newpix

     call put_image

     mov  eax,5

     mov  ebx,1

     int  0x40

     dec  esi

     jnz  newcycle

     mov  eax,0

     mov  edi,0x1000

     mov  ecx,512*256*3 / 4 +50

     cld

     rep  stosd

     popa

     call draw_fractal

     ret

; **********************************************************************

;

;    Tinyfrac

;

draw_fractal:

        pusha

        mov     eax,4

        mov     ebx,15*65536+35

        mov     ecx,0xffffff

        mov     edx,calc

        mov     esi,calcl-calc

        int     0x40

        popa

        pusha

        movzx   ebp,word [STARTX]

        movzx   edi,word [STARTY]

;       This routine is the fractal drawing engine.  It has been

;       optimized for size, sacrificing speed.

        mov     cx, PIXHEIGHT   ; height of screen in pixels

        sub     di,cx           ; adjust our Y offset

@@CalcRow:

        push    cx

;        and     cl,0x7

;        cmp     cl,0

;        jne     noim

;        call    put_image

;     noim:

        mov     cx, PIXWIDTH -1  ; width of screen in pixels

        sub     bp,cx           ;

@@CalcPixel:

        push    cx              ; save the column counter on stack

        xor     cx, cx          ; clear out color loop counter

        xor     bx, bx          ; zero i coefficient

        xor     dx, dx          ; zero j coefficient

@@CycleColors:

        push    dx              ; save j value for later

        mov     ax, bx          ; ax = i

        sub     ax, dx          ; ax = i - j

        add     dx, bx          ; dx = i + j

        stc                     ; one additional shift, please

        call    Shifty          ; ax = ((i+j)*(i-j)) shifted right

        pop     dx              ; retrieve our saved value for j

        add     ax,bp           ; account for base offset...

        cmp     ah,THRESHOLD    ; Q: is i > THRESHOLD * 256?

        xchg    bx,ax           ; now swap new i with old i

        jg      @@draw          ; Y: draw this pixel

        clc                     ; no additional shifts here, please

        call    Shifty          ; now dx:ax = old i * j

        xchg    dx,ax           ;

        add     dx,di           ; account for base offset...

        inc     cl              ; increment color

        jnz     @@CycleColors   ; keep going until we're done

@@draw:

        xchg    ax, cx          ; mov color into al

        pop     cx              ; retrieve our column counter

        pop     dx              ; fetch row (column already in cx)

        push    dx              ; must leave a copy on the stack

        xor     bx,bx           ; write to video page zero

        call    put_pixel

        inc     bp

        loop    @@CalcPixel

        inc     di

        pop     cx

        loop    @@CalcRow

        call    put_image

        popa

        ret

put_image:

        pusha

        mov  eax,7

        mov  ebx,0x1000

        mov  ecx,512*65536+255

        mov  edx,10*65536+30

        int  0x40

        popa

        ret

shlc db 0

put_pixel:

        pusha

        sub     edi,[STARTY]

        sub     ebp,[STARTX]

        and     edi,0xff

        and     ebp,0x1ff

        shl     edi,9

        mov     ebx,edi ; * 3 - Y

        add     edi,ebx

        add     edi,ebx

        mov     ebx,ebp

        add     ebp,ebx

        add     ebp,ebx

        add     edi,ebp

        mov     cl,[shlc]

        mov     ebx,0xff

        shl     ebx,cl

        add     cl,3

        shl     eax,cl

        and     eax,ebx

        mov     [0x1000+edi],eax

        popa

        ret

;****************************************************************************

 ;

 ;       This routine multiplies AX by DX and shifts the result (in

;       DX:AX) to the right by scale bits (or scale+1 bits if CY is

;       set).  The resulting value is left in AX.  DX is destroyed.

;

;****************************************************************************

Shifty:

        push    cx              ; save middle bits (i*i - j*j)

        db      0b1h            ; code for mov cl,immed8

scale   db      STARTSCALE

        adc     cl,0            ; adjust per CY flag

        imul    dx              ; do the multiply

        xchg    ax,dx           ;

        shl     eax,16          ; put hi part in hi 16 bits

        xchg    ax,dx

        shr     eax,cl          ;

        pop     cx              ;

        ret                     ;

; **********************************************************************

;

;                   WINDOW DEFINITIONS AND DRAW

;

; **********************************************************************

draw_window:

      pusha

      mov  eax,12

      mov  ebx,1

      int  0x40

      mov  eax,0

      mov  ebx,50*65536+531

      mov  ecx,100*65536+256+48

      mov  edx,0x02334455

      mov  esi,0x80778899

      mov  edi,0x00778899

      int  0x40

      mov  eax,8

      mov  ebx,(531-19)*65536+12

      mov  ecx,5*65536+12

      mov  edx,1

      mov  esi,0x808080

      int  0x40

      mov  eax,8

      mov  ebx,300*65536+112

      mov  ecx,5*65536+12

      mov  edx,2

      mov  esi,0x808080

      int  0x40

      mov  ebx,430*65536+12

      mov  ecx,5*65536+12

      mov  edx,3

      mov  esi,0xa00000

      mov  edi,3

    newcolor:

      mov  eax,8

      int  0x40

      add  ebx,13*65536

      shr  esi,8

      inc  edx

      dec  edi

      jnz  newcolor

      mov  eax,4

      mov  ebx,8*65536+8

      mov  ecx,0xffffff

      mov  edx,l

      mov  esi,ll-l

      int  0x40

      mov  eax,12

      mov  ebx,2

      int  0x40

      popa

      ret

; ***************************************************************

;

;     DATA AREA

;

l:  db 'TINYFRAC - MOVE: ARROWS, ZOOM Q/W, CYCLE: E/R     '

    db 'SET AS WALLPAPER'

ll:

calc   db 'CALCULATING'

calcl:

I_END: