Assembler

A couple of years ago I develped a few assembler programs.

A screen shot from one of the assembler programs

You can download my asm programs with source here.

Note: The file is compressed with WinRar.

A small assembler program

The following code demonstrates how a to make a small program in assembler.
The program displays some scrolling graphics (palette rotating).
The size of executable file is just 620 bytes!

 ;---------------------------------------------------------------------
; cw is made by NJLO/The Candidate - 1995
; optimized version
;---------------------------------------------------------------------
TITLE cw
.MODEL TINY
.CODE
JUMPS
ORG 100H
;---------------------------------------------------------------------
BEGYND:     JMP INIT
;---------------------------------------------------------------------
; this text is displayed when the program terminates
end_txt db 'Coded by The Candidate',13,10,10
db ' -=BBS CYBERWORLD=-',13,10
db '   SysOp Jimmy',13,10
db ' CoSysOp The Death',13,10
db '  CoSysOp Zealot',13,10
db '  CALL DK-56219202',13,10,10,'$'
; blue color from pallette (15x15=225, notice not all 256 colors)
bluepal db 16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16
db 16,16,16,16,16,16,16,16,16, 16,16,16,16,16,16,16,16,16,16,16,16,16,16
db 16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16, 16,16,42,42,16,42,42,
db 16,42,42,42,42,16,16,16,16,16,42,42,42,42,42,16,42,16,16,42,42,16,16
db 16,16,42,16,42,16,42,16,16,16,16,16,42,16,16,16,16,42,16,42,16,42,16
db 16,16,16,16,42,16,16, 16,16,42,16,16,16,42,16,16,16,16,16,42,16,16,16
db 16,42,16,16,16,42,16,42,16,16,42,42,16,16, 16,16,42,16,16,16,42,16,42 
db 42,42,42,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16, 16
db 16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16, 16
db 16,16,16,16,16,16,16,16,16, 16,16,16,16,16,16,16,16,16,16,16,16
;--------------------------------------------------------------------------
; input: [screenseg:bx] = screen position, ah = start color
is_line macro
mov   dh,21
is_l1: dec   dh
mov   cx,15  ; loop 15 colors out
is_l2: mov   [bx],ah
dec   ah
inc   bx
loop  is_l2
add   ah,15
cmp   dh,0    
jne   is_l1
mov   [bx],ah ; last five pixels of line
inc   bx
dec   ah
mov   [bx],ah
inc   bx
dec   ah
mov   [bx],ah
inc   bx
dec   ah
mov   [bx],ah
inc   bx
dec   ah
mov   [bx],ah
inc   bx
sub   ah,11
endm
;---------------------------------------------------------------------
move_bckgrnd_pal macro
mov   bx,OFFSET bluepal    ; bx -> bluepal
xor   cl,cl       
ms_1:  mov   al,15       
mul   cl        
add   bx,ax       
mov   dh,[bx+14]    
mov   ah,[bx+13]    
mov   [bx+14],ah
mov   ah,[bx+12]     
mov   [bx+13],ah
mov   ah,[bx+11]     
mov   [bx+12],ah
mov   ah,[bx+10]     
mov   [bx+11],ah
mov   ah,[bx+9]     
mov   [bx+10],ah
mov   ah,[bx+8]     
mov   [bx+9],ah
mov   ah,[bx+7]     
mov   [bx+8],ah
mov   ah,[bx+6]     
mov   [bx+7],ah
mov   ah,[bx+5]     
mov   [bx+6],ah
mov   ah,[bx+4]     
mov   [bx+5],ah
mov   ah,[bx+3]     
mov   [bx+4],ah
mov   ah,[bx+2]     
mov   [bx+3],ah
mov   ah,[bx+1]     
mov   [bx+2],ah
mov   ah,[bx]     
mov   [bx+1],ah
mov   [bx],dh
inc   di           
inc   cl           ; increment counter (i)
xor   ah,ah
sub   bx,ax          
cmp   cl,15
jne   ms_1
endm
;---------------------------------------------------------------------
;---------------------------------------------------------------------
;---------------------------------------------------------------------
INIT:      mov ax,13h   ; ah=0 and al=13h = 320x200, 256 colors
INT 10h
;---------------------------------------------------------------------
; Initialize screen (boxes 15x15)        
xor   bx,bx  ; zero position
mov   ah,225 ; start color
mov   cx,0a000h
push  ds
mov   ds,cx
mov   dl,15
is_1:      is_line ; draw one line
dec   dl
cmp   dl,0
jne   is_1
mov   cx,29600    ; rest 185 lines
mov   bx,4800     ; first 15 lines
xor   si,si      ; ScrSeg:si -> first screen pixel
is_2:      mov   ax,[si]
mov   [bx],ax
inc   si
inc   si
inc   bx
inc   bx
loop  is_2
pop   ds    
;---------------------------------------------------------------------
main1: move_bckgrnd_pal
; set background palette        
mov   si,OFFSET bluepal    ; si -> blue palette (225 colors)
MOV  DX,3dah          ; WAIT FOR VERTICAL BLANKING
WV_1:  IN  AL,DX
TEST AL,8
JZ  WV_1
mov cx,226
mov dx,03c8h
xor al,al
out dx,al
inc dx    
pal1:  out dx,al
xor al,al
out dx,al
mov al,28
out dx,al
lodsb
loop pal1
mov   ah,1 ; check if key is pressed
int   16h  
jz main1 ; if key not pressed jump to main1
;---------------------------------------------------------------------
MOV   AH,7h      ; remove key
INT   21h
MOV   AX,3    ; text mode
INT   10h
MOV   DX,OFFSET end_txt
MOV   AH,9h  ; write string ( dx -> string)
INT   21h
MOV   AH,4ch ; exit to dos
INT   21h
END       BEGYND
;---------------------------------------------------------------------

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A small assembler program

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