Dracarys by Desire [web]
; "Dracarys" 128b intro for Outline 2019
; by HellMood / DESiRE
; 1024x768 fractal, compatible to every dos
; https://www.youtube.com/watch?v=WWGhEdefiGY
org 100h ; "=)" means "wasting bytes"
mov bx,0x105 ; safe, compatible, way of setting =)
mov ax,0x4f02 ; 1024x768x256 VESA, shared int10
mov si,z-2 ; pointing to zoom/imag/real
fldz ; x (stack)
mov dx,768 ; rows ; 1byte for speed up =)
x: fldz ; y x (stack)
mov ch,4 ; number of columns = 1024
y: int 0x10 ; set pixel/ set mode
fld st1 ; x y x (stack)
fld st1 ; y x y x (stack)
p: fld st1 ; x y x y x (stack)
fmul st2,st0 ; x y xx y x (stack)
fld st1 ; y x y xx y x (stack)
fmul st0,st0 ; yy x y xx y x (stack)
fsub dword [si-z+r] ; yy' x y xx y x (stack)
fsubp st3,st0 ; x y xx-yy' y x (stack)
fmulp st1,st0 ; xy xx-yy' y x (stack)
fadd st0,st0 ; 2xy xx-yy' y x (stack)
fadd dword [si-z+i] ; 2xy' xx-yy' y x (stack)
ficom word [si] ; compare for bailout
fnstsw ax ; status word -> ax
sahf ; load compare flag
inc bx ; iteration++, zero flag?
ja p ; combined flag testing
xchg bx,ax ; color=iter, reset iteration
mov ah,0x0c ; int10mode=set pixel
add al,-43 ; beautify, just for 1st frame =)
fcompp ; y x (stack)
fadd dword [si] ; y' x (stack)
loop y ; next pixel
fstp st0 ; x (stack)
fadd dword [si] ; x' (stack)
sub dx,byte 1 ; two bytes more for perfection =)
jnc x ; next line
pal: mov cx,258 ; make palette cyclable =)
mov dx,0x3c9 ; port for RGB values
P: imul bx,cx,byte 4 ; * bl = 4 times {0..255}
mov al,bl ; original palette code by RRROLA*
sar al,1 ; * al = {0..63,-64..0}
je Q ; * al==0: cycle RGB->GBR
jns R ; i couldnt find better colors
not al ; or time to save bytes here
R: out dx,al ; * = {0..63,63..0}
mul bl ; so i took this code
shr ax,7 ; * {0..63,63..0} * {0..255} / 128
Q: out dx,al ; * = {63..48..0,0..16..63}
mul al ; and modified it for cycling
shr ax,6 ; while keeping the original
out dx,al ; * = {62..36..0,0..4..62}
loop P ; comments, kudos to RRROLA*
out dx,al ; triple out alignment for cycling
mov al,155 ; set timer to ~30 FPS =)
out 40h,al ; to smooth & save on VSYNC =)
hlt ; wait to next timer event
in al,0x60 ; read keyboard =)
dec ax ; ah=0 from shr above! =)
jnz pal ; keep cylcing until ESC
mov al,3 ; set textmode =)
int 0x10 ; before exiting =)
ret ; then exit
z:dw 0x38d0 ; zoom value
i:dw 0x3e36 ; imag value
r:dw 0xbf4d ; real value[ back to the prod ]