Games of Daze

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Assembly Source File | 1994-12-04 | 11.3 KB | 319 lines

; Smooth vertical scroller by Patch - hamell@cs.pdx.edu ; Made for the intro Motion by Avalanche ; Done sometime in December 1993 ; ; If you use this code in any manner, please inform me. ; ; If you want to be cool, modify this so the number of lines can be unlimited. ; If you do so, please email me the new source code. .model small .stack 1024 .386 .data linecount db 0 screen_offs dw 160 include status.inc include motion-a.inc .code TOPSCREENOFFS EQU 160 LINECOMPAREVAL EQU 367 VIEWLINES EQU 23 PIXELSTEP EQU 2 NUMSTEPS EQU 14/PIXELSTEP include key.inc WaitVRetrace MACRO LOCAL VRetrace,NoVRetrace mov dx,03dah VRetrace: in al,dx test al,00001000b jnz VRetrace NoVRetrace: in al,dx test al,00001000b jz NoVRetrace ENDM WaitVActive MACRO LOCAL VActive mov dx,03dah VActive: in al,dx test al,00001000b jnz VActive ENDM WaitVInactive MACRO LOCAL VInactive mov dx,03dah VInactive: in al,dx test al,00001000b jz VInactive ENDM WaitHRetrace MACRO LOCAL HRetrace,NoHRetrace mov dx,03dah HRetrace: in al,dx test al,00000001b jnz HRetrace NoHRetrace: in al,dx test al,00000001b jz NoHRetrace ENDM WaitHActive MACRO LOCAL HActive mov dx,03dah HActive: in al,dx test al,00000001b jnz HActive ENDM WaitHInactive MACRO LOCAL HInactive mov dx,03dah HInactive: in al,dx test al,00000001b jz HInactive ENDM Set_Start_Addr MACRO mov bx,[screen_offs] ; set starting address mov dx,03d4h mov al,0ch mov ah,bh out dx,ax inc al mov ah,bl out dx,ax ENDM start: mov ax,@data mov ds,ax call _Set_New_Int9 mov ax,0003h int 10h mov ax,0100h ; hide the cursor mov cx,0800h int 10h WaitVRetrace push LINECOMPAREVAL call _Set_Line_Compare add sp,2 Set_Start_Addr WaitVRetrace cld mov ax,0b800h ; dump status bar to screen mov es,ax xor di,di mov si,offset STATUSBAR mov cx,STATUSBAR_LEN rep movsw mov di,[screen_offs] ; dump ansi to screen shl di,1 ; *2, each offset is 2 bytes mov si,offset ANSI_SCREEN ; add si,160 mov cx,ANSI_DEPTH*80 rep movsw get_key: ; cmp cs:[_keynumpress],0 ; je get_key cmp cs:_keys[kUARROW],1 ; cursor up? je key_up cmp cs:_keys[kKEYPAD8],1 ; cursur up? je key_up cmp cs:_keys[kDARROW],1 ; cursor down? je key_down cmp cs:_keys[kKEYPAD2],1 ; cursor down? je key_down cmp cs:_keys[kHOME],1 ; home? je key_home cmp cs:_keys[kEND],1 ; end? je key_end cmp cs:_keys[kPGUP],1 ; pgup? je key_pgup cmp cs:_keys[kPGDN],1 ; pgdn? je key_pgdn cmp cs:_keys[kESC],1 ; esc? je exit jmp get_key key_up: cmp [linecount],0 ; at top? je get_key ; if so, jump dec [linecount] sub [screen_offs],80 ; one line up WaitVRetrace Set_Start_Addr mov bx,1008h ; start at char line 14 mov cx,NUMSTEPS pan_up: WaitVInactive WaitHActive sub bh,PIXELSTEP ; next line of char mov dx,03d4h mov ax,bx out dx,ax dec cx jnz pan_up WaitVInactive WaitHActive mov dx,03d4h mov ax,0008h ; set char line to 0 out dx,ax jmp get_key key_down: cmp [linecount],ANSI_DEPTH-VIEWLINES je get_key inc [linecount] add [screen_offs],80 mov bx,0008h ; start at char line 0 mov cx,NUMSTEPS pan_down: WaitVInactive WaitHActive add bh,PIXELSTEP ; next char line mov dx,03d4h mov ax,bx out dx,ax dec cx jnz pan_down WaitVRetrace Set_Start_Addr WaitVInactive WaitHActive mov dx,03d4h mov ax,0008h ; set char line to 0 out dx,ax jmp get_key key_home: cmp [linecount],0 je get_key mov [linecount],0 mov [screen_offs],TOPSCREENOFFS WaitVRetrace Set_Start_Addr jmp get_key key_end: cmp [linecount],ANSI_DEPTH-VIEWLINES je get_key mov [linecount],ANSI_DEPTH-VIEWLINES mov [screen_offs],(ANSI_DEPTH-VIEWLINES)*80 add [screen_offs],TOPSCREENOFFS WaitVRetrace Set_Start_Addr jmp get_key key_pgup: cmp [linecount],0 ; at top line? je get_key cmp [linecount],24 ; full screen left to view? jbe key_home ; if not, jump sub [linecount],VIEWLINES sub [screen_offs],80*VIEWLINES WaitVActive Set_Start_Addr mov cx,8 pan_pgup: WaitVRetrace dec cx jnz pan_pgup jmp get_key key_pgdn: cmp [linecount],ANSI_DEPTH-VIEWLINES ; at bottom line? je get_key cmp [linecount],ANSI_DEPTH+1-VIEWLINES*2 ; full screen to view? jae key_end ; if not, jump add [linecount],VIEWLINES add [screen_offs],80*VIEWLINES WaitVRetrace Set_Start_Addr mov cx,8 pan_pgdn: WaitVRetrace dec cx jnz pan_pgdn jmp get_key exit: call _Set_Old_Int9 mov ax,0003h ; text mode 3 int 10h mov ax,4c00h ; exit int 21h ;****************************************************************************** ;* PROC : void Set_Line_Compare(word rasterline); ;* Purpose : Sets the line compare ;* The area above the line compare is the segment and offset where ;* the start address is set to. ;* The area below the line compare is at A000:0000. ;* Entrance: rasterline - the raster line to set for line compare ;* for every pixel line, there are 2 raster lines ;* so pixel line 100 is raster line 200 ;* Exit : nothing ;****************************************************************************** _Set_Line_Compare PROC NEAR push bp mov bp,sp mov bx,[bp + 4] ; BX = line value mov dx,03d4h ; CRTC reg mov al,09h ; 09h = max scan line index out dx,al ; 10th bit of line compare inc dl ; goes in bit 6 of the index in al,dx ; read in previous contents mov ah,bh ; get bit 10 of line compare or ah,11111101b ; make other bits 1 as a mask ror ah,03h ; move to bit 6 and al,ah ; AND them together out dx,al dec dl ; 03d4h mov al,07h ; 07h = overflow index out dx,al ; 9th bit of line compare inc dl ; goes in bit 4 of the index in al,dx ; read in previous contents mov ah,bh ; get bit 9 of line compare or ah,11111110b ; make other bits 1 as a mask rol ah,04h ; move to bit 4 and al,ah ; AND them together out dx,al dec dl ; 03d4h mov al,18h ; 18h = line compare index mov ah,bl ; AH = lower 8 bits out dx,ax pop bp ret _Set_Line_Compare ENDP END start