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Assembly Source File | 1990-02-02 | 15.8 KB | 843 lines

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; expa.asm - support routines for EXPLOD.C. Compile with "masm /mx expa ;". ; ; NOTE: ; Make sure one of DLC or TURBOC is defined below. C compilers other ; than Datalight C and Turbo C will probably require changes to the ; segment naming. This file has been tested with the Arrowsoft Assembler ; 1.00d and MASM 5.0. ; ; (C) 1989 Dennis Lo ; You are free to use and distribute this source code, provided that the ; authors' names remain in the code, and that modified versions are clearly ; distinguished from the original. ; ; 89/06/24 Dennis Lo (V1.0) Initial release. ; 89/07/03 Dennis Lo (V1.1) Added ifdefs for linking with Turbo C. ; 89/07/26 Erik Liljencrantz Added EGA support with autodetection ; Restores previous CRT textmode on exit ; 89/08/22 Dennis Lo (V1.2) Allow frame buffer to be in any segment ; Optimized HGC/CGA frame draw loop ; Restricted EGA colours to only the bright ones ; to get rid of the flickering effect. ; 89/09/03 Erik Liljencrantz Added VGA support with autodetection ; 89/09/23 Dennis Lo Added DOS memory allocation routines ; Cosmetic changes. ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;------------------------------------------------------------------ ; *** IMPORTANT: Uncomment one of the following *** ; ; uncomment this for Datalight C ******* ;DLC equ 1 ; ; uncomment this for Turbo C ******** TURBOC equ 1 ; ;------------------------------------------------------------------ ;;;;;;;;;;;;;;;;;;;;;;;;; SEGMENT NAMES ;;;;;;;;;;;;;;;;;;;;;;;;; ;segment names for Datalight C ifdef DLC pgroup group prog prog segment byte public 'prog' assume cs:pgroup prog ends dgroup group data data segment word public 'data' assume ds:dgroup data ends endif ;segment names for Turbo C ifdef TURBOC name t _TEXT segment byte public 'CODE' DGROUP group _DATA,_BSS assume cs:_TEXT,ds:DGROUP,ss:DGROUP _TEXT ends _DATA segment word public 'DATA' _d@ label byte _DATA ends _BSS segment word public 'BSS' _b@ label byte _BSS ends endif ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; CONST ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; HGC port addresses config equ 03bfh index equ 03b4h cntrl equ 03b8h ; HGC control codes scrn_on equ 8 grph equ 2 text equ 20h par equ 4 ;stack offset of 1st C call parameter DEADPOINT equ 32767 ;flag for dead point in frame table ;;;;;;;;;;;;;;;;;;;;;;;;;;;;; DATA ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ifdef DLC data segment word public 'data' endif ifdef TURBOC _DATA segment word public 'DATA' endif Vidtype db ? ;video card type Vidseg dw ? ;video mem segment Vidsize dw ? ;video mem size SaveMode DB ? ;Save video text mode Color db ? ;Current frame colour (for EGA) ; Table of bit values for plotting points ;masktable db 128,64,32,16,8,4,2,1 ;1-pixel wide points masktable db 192,96,48,24,12,6,3,1 ;2-pixel wide points ; HGC 6845 config tables hgc_gtable db 35h,2dh,2eh,07h db 5bh,02h,57h,57h db 02h,03h,00h,00h hgc_ttable db 61h,50h,52h,0fh db 19h,06h,19h,19h db 02h,0dh,0bh,0ch ; Palette register table for EGA ; Consists of colour values for registers 0-15, plus border colour palette db 00h,07h,3ah,3bh,3ch,3eh,3fh,07h db 3ah,3bh,3ch,3eh,07h,3ah,3bh,3ch,00h ifdef DLC data ends endif ifdef TURBOC _DATA ends endif ;;;;;;;;;;;;;;;;;;;;;;;;;;;;; CODE ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ifdef DLC prog segment byte public 'prog' endif ifdef TURBOC _TEXT segment byte public 'CODE' endif ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Return the number of paragraphs of memory available. ; int num_para = DosMemLeft (); ; public _DosMemLeft _DosMemLeft proc near push bp mov bp,sp push es mov bx,0f000h ;Call DOS malloc with a request for mov ah,48h ; 960K to make sure it fails int 21h jc memleft_cont xor ax,ax ;Error: DOS malloc() succeeded! jmp memleft_end ;Return 0 memleft_cont: mov ax,bx ;Return mem size remaining memleft_end: pop es pop bp ret _DosMemLeft endp ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Allocate a block of memory ; int segment_addr = DosAlloc (size_in_paragraphs); ; Returns 0 if unsucessful. ; public _DosAlloc _DosAlloc proc near push bp mov bp,sp push es mov bx,par[bp] ;get # paragraphs requested ; add bx,15 ;# paragraphs = (# bytes + 15) / 16 ; shr bx,1 ; shr bx,1 ; shr bx,1 ; shr bx,1 mov ah,48h ;call DOS malloc int 21h jnc alloc_end xor ax,ax ;if failure then return 0 alloc_end: pop es pop bp ret _DosAlloc endp ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Free a block of memory allocated by DosAlloc ; DosFree (int segment_addr); ; Returns 0 if successful, 1 if not. ; public _DosFree _DosFree proc near push bp mov bp,sp push es mov ax,par[bp] ;get segment address to free at mov es,ax mov ah,49h ;call DOS free int 21h jc free_end ;if error then return DOS err code xor ax,ax ;else return 0 free_end: pop es pop bp ret _DosFree endp ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Nonblocking keyboard read - returns ASCII char ; int key = ChkKey(); ; public _ChkKey _ChkKey proc near push si push di mov ah,1 int 16h jz nokey ;if no key then return mov ax,0 ;else get the key out of the buffer int 16h mov ah,0 jmp chkret nokey: mov ax,0 chkret: pop di pop si ret _ChkKey endp ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Guess video card type. Returns 'h', 'c', 'e', or 'v'. ; int card = gr_card(); ; public _gr_card _gr_card proc near push bp push si push di mov ah,0Fh int 10h MOV SaveMode,AL ;Save textmode to restore later... MOV BL,AL mov ax,'h' ; Mono, assume HGC cmp bl,07h ; je card_done ; MOV AX,1200h MOV BX,0FF10h MOV CX,00FFh INT 10h CMP CL,12 ;CL<12 JAE Card_CGA CMP BH,1 ;BH<=1 JA Card_CGA CMP BL,3 ;BL<=3 JA Card_CGA ;OK, either EGA or VGA ;Use INT 10/AH=1A00 to determine which one... MOV AX,1A00h INT 10h CMP AL,1Ah ;Returns AL=1Ah if function supported JNE Card_EGA CMP BL,08h ;VGA with analog color display JNE Card_EGA MOV AX,'v' ;Assume VGA JMP SHORT Card_Done Card_EGA: MOV AX,'e' ;Assume EGA JMP SHORT Card_Done Card_CGA: MOV AX,'c' ;Assume CGA Card_Done: pop di pop si pop bp ret _gr_card endp ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Set video card type ; gr_setcard (char video_card); ; public _gr_setcard _gr_setcard proc near push bp mov bp,sp mov ax,par[bp] ;get video_card parameter mov Vidtype,al ;Set video mem segment cmp al,'h' jne not_herc mov ax,0b000h ;Hercules mov cx,8000h ; 32K bytes jmp s_end not_herc: cmp al,'e' jne not_ega mov ax,0A000h ;EGA mov cx,6D60h ; 28000 bytes (but in four planes) jmp s_end not_ega: cmp al,'v' jne not_vga mov ax,0A000h ;VGA mov cx,9600h ; 38400 bytes (but in four planes) jmp s_end not_vga: mov ax,0b800h ;CGA mov cx,4000h ; 16K bytes s_end: mov Vidseg,ax mov Vidsize,cx pop bp ret _gr_setcard endp ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Set video card for graphics mode ; gr_gmode(); ; public _gr_gmode _gr_gmode proc near push bp push es push ds push si mov al,Vidtype cmp al,'h' jne NotHerc call hgc_gmode ;HGC jmp g_end NotHerc: cmp al,'e' jne NotEga call ega_gmode ;EGA jmp g_end NotEga: cmp al,'v' jne NotVga call vga_gmode ;VGA jmp g_end NotVga: call cga_gmode ;CGA g_end: pop si pop ds pop es pop bp ret _gr_gmode endp ;Set HGC graphics mode, page 0 hgc_gmode: mov dx,config mov al,3 out dx,al mov al,grph lea si,hgc_gtable mov bx,0 mov cx,4000h call hgc_setmd ret ;Set EGA graphics mode ega_gmode: mov ah,00h ;Set 640x350 16-colour mode mov al,10h ;Probably one of the few changes for VGA int 10h ;640x480 resolution mov ax,ds ;set colour palette mov es,ax lea dx,palette mov ax,1002h int 10h ret ;Set VGA graphics mode vga_gmode: mov ah,00h ;Set 640x350 16-colour mode mov al,12h ;Mode 12h: 640x480 in 16 colours int 10h mov ax,ds ;set colour palette mov es,ax lea dx,palette mov ax,1002h int 10h ret ;Set CGA graphics mode cga_gmode: mov ah,00h ;set 320x200 4-colour mode mov al,04h int 10h mov ah,0bh ;set green-red-brown colour palette mov bx,0100h int 10h ret ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Set text mode. ; gr_tmode(); public _gr_tmode _gr_tmode proc near push bp push es push ds push si mov al,Vidtype cmp al,'h' jne t_cga t_hgc: call hgc_tmode jmp t_end t_cga: call cga_tmode ;for CGA, EGA, & VGA t_end: pop si pop ds pop es pop bp ret _gr_tmode endp ;Set HGC text mode hgc_tmode: mov dx,config mov al,0 out dx,al mov al,text lea si,hgc_ttable mov bx,720h mov cx,2000h call hgc_setmd ret ;Set CGA & EGA & VGA text mode cga_tmode: mov ah,00h mov al,SaveMode ;Restore previous textmode int 10h ret ;;;;;;;;;;;;;;;;;;;;;;;;; hgc_setmd (Hercules support) ; Set display mode to graphics or text. Local. ; params: ; al = value to be output to 6845 control port ; si = 6845 param table ; cx = # of words to be cleared ; bx = blank value hgc_setmd proc near push di push ds push es push ax push bx push cx ; change mode but without scrn_on mov dx,cntrl out dx,al ; initialize the 6845 mov ax,ds mov es,ax ;also point es:si to param table mov dx,index mov cx,12 ;12 params to be output xor ah,ah ;starting from reg. 0 parms: mov al,ah out dx,al ;output 6845 reg. index inc dx lodsb out dx,al ;output 6845 reg. data inc ah dec dx loop parms ; clear the display buffer pop cx mov ax,0b000h cld mov es,ax xor di,di pop ax rep stosw ; scrn_on, page 0 mov dx,cntrl pop ax add al,scrn_on out dx,al pop es pop ds pop di ret hgc_setmd endp ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Returns video mem addr of a (x,y) point ; int video_addr = gr_addr (int x, int y); ; par_x equ par ;in: x par_y equ 2+par ;in: y public _gr_addr _gr_addr proc near push bp mov bp,sp push si push di mov bx,par_x[bp] mov cx,par_y[bp] call graddr pop di pop si pop bp ret _gr_addr endp ; ;Local routine to calculate video address. ;On entry, BX=x, CX=y. Returns addr in AX. ; graddr proc near mov al,Vidtype cmp al,'h' je hgc_addr cmp al,'e' je ega_addr cmp al,'v' je vga_addr jmp cga_addr graddr endp ;Calc HGC addr = 90 * (y / 4) + 2000h * (y & 3) + x / 8 hgc_addr: ;loc = (y / 4) * 90 mov ax,cx shr ax,1 shr ax,1 ;ax * 90 = ax*2 + ax*8 + ax*16 + ax*64 shl ax,1 ;*2 mov dx,ax shl ax,1 ;*4 shl ax,1 ;*8 add dx,ax shl ax,1 ;*16 add dx,ax shl ax,1 ;*32 shl ax,1 ;*64 add ax,dx MOV DI,AX ;store sum in DI ;loc += (y & 3) * 2000H AND CX,3 MOV AX,2000H MUL CX ;(msb ignored) ADD DI,AX ;loc += (x / 8) mov ax,bx shr ax,1 shr ax,1 shr ax,1 add ax,di ret ;Calc EGA addr = 80 * y + x / 8 ega_addr: vga_addr: MOV AX,cx SHL AX,1 SHL AX,1 SHL AX,1 SHL AX,1 MOV DX,AX SHL AX,1 SHL AX,1 ADD DX,AX MOV AX,bx SHR AX,1 SHR AX,1 SHR AX,1 ADD AX,DX RET ;Calc CGA addr = 80 * (y / 4) + 2000h * (y & 3) + x / 8 cga_addr: ;loc = (y / 2) * 80 MOV AX,cx SHR AX,1 MOV DL,80 MUL DL MOV DI,AX ;store sum in DI ;loc += (y & 1) * 2000H MOV AX,2000H AND CX,1 jz ca_noadd ADD DI,AX ca_noadd: ;loc += (x / 8) MOV AX,bx shr ax,1 shr ax,1 shr ax,1 ADD ax,di ret ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Returns video mem addr of a (x,y) point ; int video_addr = gr_addr (int x, int y); ; public _gr_value _gr_value proc near push bp mov bp,sp mov bx,par_x[bp] call grvalue pop bp ret _gr_value endp ; ; Local: returns the byte value of a (x,y) point in AL ; Input: BX=x ; Output: AL = 2 << [7 - (x & 7)] ; grvalue proc near and bx,7 mov al,masktable[bx] ret grvalue endp ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; gr_store_pt (x, y, dest_seg, dest_ofs, centre_addr) ; dest_seg equ par+4 dest_ofs equ par+6 cent_addr equ par+8 public _gr_store_pt _gr_store_pt proc near push bp mov bp,sp push es push si push di mov bx,par_x[bp] ;get addr cmp bx,DEADPOINT je store_dead mov cx,par_y[bp] call graddr sub ax,cent_addr[bp] mov dx,ax mov bx,par_x[bp] ;get value call grvalue mov cl,al store_pt: mov bx,dest_ofs[bp] ;get dest addr mov ax,dest_seg[bp] mov es,ax mov es:[bx],dx ;store addr in dest mov es:[bx+2],cl ;store value in dest pop di pop si pop es pop bp ret _gr_store_pt endp store_dead: mov dx,bx jmp store_pt ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Plot one frame of 3-byte (offset, value) point records. ; gr_frplot (num_points, frame_seg, frame_offset, centre_addr, draw_or_erase) ; fpar_nump equ par ;No. of points per frame fpar_frm_seg equ par+2 ;frame segment fpar_frm_ofs equ par+4 ;frame offset fpar_centre equ par+6 ;video addr of explosion's centre fpar_mode equ par+8 ;for EGA: 0 means erase, 1 means draw public _gr_frplot _gr_frplot proc near push bp mov bp,sp push ds push es push si push di mov cx,fpar_nump[bp] mov si,fpar_frm_ofs[bp] mov dx,fpar_centre[bp] mov di,3 cmp VidType,'e' je fr_ega cmp VidType,'v' je fr_vga ;Plot frame on HGC or CGA fr_cga_hgc: mov ax,Vidseg ;get video segment mov es,ax mov ax,fpar_frm_seg[bp] ;get frame table segment mov ds,ax frloop: mov bx,[si] ;get point offset add bx,dx ;add centre to offset mov al,[si+2] ;get point's byte value xor es:[bx],al frnext: add si,di loop frloop fr_end: pop di pop si pop es pop ds pop bp ret ;Plot frame on EGA fr_vga: fr_ega: MOV BL,fpar_mode[BP] MOV AX,00F02H push dx MOV DX,03C4H ;3C4 OUT DX,AX ;Map Mask = enable write in all planes MOV DX,03CEH MOV AX,0FF01H OUT DX,AX MOV AX,00005H OUT DX,AX ;Mode register CMP BL,0 JE fr_Clear MOV AX,01803H OUT DX,AX ;Select XOR of data INC Color ;Increment colorcounter MOV AH,Color ;Alternative coloring of the explosion... ; MOV AX,40h ;Get color from timer...! ; MOV ES,AX ; ; MOV AH,ES:[06Ch] ; ;Alternative explosion colouring using "random" numbers from ROM ; inc Colour ; mov ax,0f000h ; mov es,ax ; mov bl,Color ; xor bh,bh ; mov ah,es:[bx] ; or ah,ah ; and ah,15 ; jne notblack ; inc ah ;notblack: ;here ah should contain colour byte JMP SHORT fr_cont fr_Clear: MOV AX,00003H OUT DX,AX ;Select unmodified data XOR AH,AH fr_cont: XOR AL,AL OUT DX,AX MOV AL,08 OUT DX,AL ; Select register 8 again INC DX mov ax,Vidseg ;get video segment mov es,ax mov ax,fpar_frm_seg[bp] ;get frame table segment mov ds,ax pop bp ;get centre addr pushed earlier egaloop: mov bx,[si] ;get point offset cmp bx,DEADPOINT ;check if point is dead je eganext add bx,BP ;add centre to offset mov al,[si+2] ;get point's byte value OUT DX,AL XCHG AL,ES:[BX] eganext: add si,di loop egaloop JMP fr_end _gr_frplot endp ifdef DLC prog ends endif ifdef TURBOC _TEXT ends endif end