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Assembly Source File | 1988-04-12 | 24.3 KB | 500 lines

Title ChgColor page 60,132 ;------------------------------------------------------------------------ ; ChgColor - Changes the palette colors reisters on an EGA video board. ; If no command line parameters are entered the registers are ; reset to theie factory defaults. ; Parameters should be in the following format: ; ; reg:value ; ; reg - is the register number (0 - 15) ; value - The decimal value (color) for that register ; ; The semi-colon is required to seperate the register number ; from the value. (Actually any white space will do.) Each entry ; on the command line must be seperated by a space. ; ; example: ; ; chgcolor 2:45 4 15 7:196 ;------------------------------------------------------------------------ CR equ 13 ;carriage return EOS equ 0 ;End of String MAX_REG equ 15 ;max valid register MAX_COLOR equ 255 ;max valid color code segment para public 'code' assume cs:code, ds:code, es:code, ss:code org 100h start: jmp chgcolor ;skip data area prog_name db 10,13,'ChgColor - EGA color palette changer v 1.0' db 10,13,'$' prog_length db $-prog_name ;length of program signiture author db 'by John Toledo$' ;user changable registers/colors user_colors db 0 ;black db 1 ;Blue db 2 ;Green db 3 ;Cyan db 4 ;Red db 5 ;Magenta db 20 ;Brown db 7 ;Light Gray db 56 ;Dark Gray db 57 ;Light Blue db 58 ;Light Green db 59 ;Light Cyan db 60 ;Light Red db 61 ;Light Magenta db 62 ;Yellow db 63 ;White defaults db 0 ;Black db 1 ;Blue db 2 ;Green db 3 ;Cyan db 4 ;Red db 5 ;Magenta db 20 ;Brown db 7 ;Light Gray db 56 ;Dark Gray db 57 ;Light Blue db 58 ;Light Green db 59 ;Light Cyan db 60 ;Light Red db 61 ;Light Magenta db 62 ;Yellow db 63 ;White old_int10 dd ? ;------------------------------------------------------------------------ ; new_int10 - intercepts calls to INT 10h BIOS calls. If the request is ; going to attempt to change the EGA palette registers this routine will ; simply return. This leave the user selected colors in place. ;------------------------------------------------------------------------ hold_ah db ? new_int10 proc far mov cs:hold_ah,ah ;save the requested action type pushf ;push flags to immulate INT call call cs:old_int10 ;and do the call first thing cmp cs:hold_ah,10h ;was the request a palette register je reset_registers ;change ? If so, change 'em back cmp cs:hold_ah,0bh je reset_registers cmp cs:hold_ah,0h je reset_registers jmp new_int10_exit ;no changes, just leave reset_registers: push si push ds push es push cs ;set segment registers pop ds ; to current segment push cs pop es lea si,user_colors ;point to user selected colors call set_registers ;and reset palette register pop es pop ds pop si new_int10_exit: iret new_int10 endp ;------------------------------------------------------------------------ ; set_registers - set the EGA pallette registers to their factory ; defaults. These defaults may be found in the table DEFAULTS. ;------------------------------------------------------------------------ set_registers proc near push bx mov bx,0 default_loop: mov ah,byte ptr [si+bx] ;move color to AH register call SetPaletteReg ;set the pallette register inc bx ;bump up to next register number cmp bx,MAX_REG ;done all 16 (base 0) jl default_loop ;nope, gon on pop bx ret ;all done, lets go back set_registers endp ;------------------------------------------------------------------------ ; SetPaletteReg - Sets an EGA color pallete register to the color ; specified. ; ; BL - register number ; AH - color ;------------------------------------------------------------------------ SetPaletteReg proc near push ax ;save registers push bx push cx push dx push es ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; The following commented code is here in case the need arises to do ; the register change throught a BIOS call instead of the more hardware ; dependent port reads and writes. ; ; ;BL should have register number ; mov bh,ah ;move color to BH ; mov ax,1000h ;request set palette register ; int 10h ;call BIOS ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - mov ch,ah ;save reg color mov ax,40h ;load BIOS data segment address mov es,ax ;into ES mov dx,es:[63h] ;DX = CRTC address reg (3x4h) add dl,6 ;DX = Status reg (3xah) push dx ;preserve this value cli ;clear interrupts in al,dx ;reset Attribute Controller address ;flip-flop mov dl,0c0h ;DX = 3c0h mov al,bl ;AL = PaletteRegNumber out dx,al ;update one palette register mov al,ch ;AL = PaletteRegColor out dx,al ;set it pop dx ;DX = status register port in al,dx mov dl,0c0h mov al,20h ;set bit 5 of out dx,al ; Attribute controller address reg sti ;restart interrupts pop es ;restore registers pop dx pop cx pop bx pop ax ret SetPaletteReg endp stay_res_mark label byte ;keep stuff above resident ;++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ; Non-memory resident code below. ;++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ;------------------------------------------------------------------------ ; The following data was placed down here so it wouldn't remain resident. ;------------------------------------------------------------------------ bad_reg_msg db 10,13,'ERROR - invalid register number.',10,13,'$' bad_color_msg db 10,13,'ERROR - invalid color number.',10,13,'$' no_color_msg db 10,13,'ERROR - register not followed by color.' db 10,13,'$' defaults_msg db 10,13,'Factory default colors restored.$' user_msg db 10,13,'New colors set.$' parm db 80 dup(0) ;temporary string area hold_reg dw ? ;temporary register area ;------------------------------------------------------------------------ ; chgcolor - main routine for changing EGA color palette registers. It ; will reset the factory default colors if there are no command line ; parameters or set the user specified colors, if there are any, on the ; command line. ;------------------------------------------------------------------------ chgcolor proc near lea dx,prog_name ;set up to display program name mov ah,9 ;request DOS display string int 21h ;call DOS mov si,80h ;point to parm count in PSP cmp byte ptr [si],0h ;anything there ? je reset_colors ;no, reset factory defaults inc si ;make sure its not a blank line call skip_delims ;skip any white space out there cmp byte ptr[si],CR ;anything there ? je reset_colors ;no, reset factory defaults call set_up_colors ;yes, set new user colors jc err_exit ;exit if we had an error lea si,user_colors ;load addres of user EGA colors lea dx,user_msg ;show colors changed message jmp leave ;and exit reset_colors: lea si,defaults ;load addres of default EGA colors lea di,user_colors ;and copy it to the user table mov cx,8 ;length of table in words cld ;move from left to right rep movsw ;and do it lea si,defaults ;load addres of default EGA colors lea dx,defaults_msg ;show defaults set message leave: mov ah,9 ;request DOS display string int 21h ;and display color changes message call set_registers ;reset factory defaults assume es:nothing mov ax,3510h ;request get video vector address int 21h ;call DOS to do it mov word ptr [old_int10],bx ;save the offset mov word ptr [old_int10+2],ES ;save the segment lea si,prog_name ;get offset of program mov di,si ;signiture for comparison xor ch,ch ;zero out CH mov cl,prog_length ;amount to compare rep cmpsb ;do the compare jcxz installed ;already instaled ? ;no, lets install mov dx, offset new_int10 ;offset of new INT 10h mov ax,2510h ;request DOS set vector int 21h ;call DOS to do it lea dx,stay_res_mark ;load address of end of program int 27h ;old DOS terminate stay resident installed: lea si,user_colors ;load addres of user colors mov di,si ;to copy to mem res copy of program cld ;copy from left to right mov cx,8 ;amount in words to copy rep movsw ;do the move err_exit: int 20h ;old DOS terminate program chgcolor endp ;------------------------------------------------------------------------ ; set_up_colors - sets the user requested colors. It goes throught the ; command line list of registers and colors recursively calling the ; line parser until all of the command line has been processed. ; DI should be pointing to the beginning of the command line parameters. ;------------------------------------------------------------------------ set_up_colors proc near lea di,user_colors ;set address of user table xor bx,bx ;set changed counter to zero call get_reg ;get reg number (returned in AX) cmp byte ptr [si],CR ;end of the command line ? je no_color_err ;yep, get out of here cmp ax,MAX_REG ;invalid register ? jle good_reg ;nope, keep going lea dx,bad_reg_msg ;set up to display register error call display_err ;display error messages jmp set_colors_exit ;lets leave now good_reg: mov hold_reg,ax ;save the register number call get_color ;get the color we need to set (AX) cmp ax,MAX_COLOR ;invalid color (not 0 - 255) jle good_color ;nope, keep going lea dx,bad_color_msg ;set up to display bad color error call display_err ;display error messages jmp set_colors_exit ;lets leave now good_color: mov bx,hold_reg ;move register number to BX mov byte ptr [di+bx],al ;move color to user table cmp byte ptr [si],CR ;end of the command line ? je set_colors_exit ;yep, get out of here jmp set_up_colors ;no, get next guy to set no_color_err: lea dx,no_color_msg ;set up to display error call display_err ;and do it clc ;set carry to indicate error ret set_colors_exit: ret set_up_colors endp ;------------------------------------------------------------------------ ; get_color - converts the string pointed to by DI into a binary number ; and places the number in AX. It searches for a space, tab or carriage ; return which should follow a color number. ;------------------------------------------------------------------------ get_color proc near push cx push di call get_field ;get the color number string lea di,parm ;point to start of color string cmp byte ptr [di],EOS ;was it the end of the line ? je get_color_exit ;yep, get out push si ;save position in string lea si,parm ;reset SI to beginning of number call atoi ;convert it to binary (in AX) pop si ;restore position in string get_color_exit: pop di pop cx ret get_color endp ;------------------------------------------------------------------------ ; get_reg - converts the string pointed to by DI into a binary number ; and places the number in AX. It searches for the ':' (colon) which ; should follow a register and places a 0 (end of string) in its place. ;------------------------------------------------------------------------ get_reg proc near push cx push di call get_field ;get the register number string cmp byte ptr [si],CR ;was it the end of the line ? je get_reg_exit ;yep, get out push si ;save position in string lea si,parm ;reset SI to beginning of number call atoi ;convert it to binary (in AX) pop si ;restore position in string get_reg_exit: pop di pop cx ret get_reg endp ;------------------------------------------------------------------------ ; get_field - gets the next parameter from a string pointed to by SI. ; Leaves SI pointing to the next position in the string and copies the ; parameter in the to the string parm. Returns ax = 0ffffh if the parm ; is the last one in the string. ;------------------------------------------------------------------------ get_field proc near push di lea di,parm ;set up desination address call skip_delims ;go past leading spaces, tabs and : get_field_loop: cmp byte ptr [si],CR ;at end of command line parms ? je get_field_exit ;yep, get out of here cmp byte ptr [si],' ' ;at end of command line parms ? je get_field_exit ;yep, get out of here cmp byte ptr [si],':' ;at end of command line parms ? je get_field_exit ;yep, get out of here mov ah,byte ptr [si] ;copy character mov byte ptr [di],ah ; to parm string inc di ;bump up string pointers inc si jmp get_field_loop ;and keep looking for more get_field_exit: mov byte ptr [di],EOS ;mark end of string pop di ret get_field endp ;------------------------------------------------------------------------ ; skip_delims - searches the string (area) pointed to by SI for the ; first non-white space. It skips over spaces, tabs and colon characters ; and returns with SI pointed to the first non-white space. ;------------------------------------------------------------------------ skip_delims proc near push di ;save DI mov cx,128 ;set CX to max string length mov di,si ;copy SI to DI for scasb call dec di ;adjust for looping mov al,' ' ;search for space cld ;set direction to go left to right keep_looking: inc di ;point to next character repe scasb ;skip those blanks dec di ;adjust DI to correct position cmp byte ptr [di],9 ;is it a tab je keep_looking ;yep, we're done cmp byte ptr [di],':' ;is it a colon je keep_looking ;yep, we're done skip_delims_exit: mov si,di ;set SI to first non-white space pop di ;restore DI ret skip_delims endp ;------------------------------------------------------------------------ ; display_err - displays the message pointed to by the DX register and ; then displays the current contents of the temporary string parm. ;------------------------------------------------------------------------ display_err proc near mov ah,9 ;set up to display message int 21h ;call DOS to display message lea di,parm ;address of bad register string display_loop: cmp byte ptr [di],EOS ;end of the string ? je display_exit ;yep, let get out of here mov ah,2 ;request DOS display character mov dl,byte ptr [di] ;move character to DL for DOS int 21h ;display that sucker inc di ;point to next character jmp display_loop ;go get the next one display_exit: ret display_err endp ;------------------------------------------------------------------------ ; ATOI.ASM - convert ASCII string to ; 16-bit decimal integer. ; ; Copyright 1987 Ziff Communications Co. ; Ray Duncan ; ; Call with: DS:SI = address of string ; ; where 'string' is in the form ; ; [whitespace][sign][digits] ; ; Returns: AX = result ; DS:SI = address+1 of terminator ; ; other registers preserved ; ; Like the C library 'atoi', this routine gives no ; warning in the event of overflow, and terminates ; on the first invalid character. ;------------------------------------------------------------------------ blank equ 20h ; ASCII blank character tab equ 09h ; ASCII tab character atoi proc near ; ASCII to 16-bit integer push bx ; save registers push cx push dx xor bx,bx ; initialize forming answer xor cx,cx ; initialize sign flag atoi1: lodsb ; scan off whitespace cmp al,blank ; ignore leading blanks je atoi1 cmp al,tab ; ignore leading tabs je atoi1 cmp al,'+' ; if + sign proceed je atoi2 cmp al,'-' ; is it - sign? jne atoi3 ; no, test if numeric dec cx ; was - sign, set flag ; for negative result atoi2: lodsb ; get next character atoi3: cmp al,'0' ; is character valid? jb atoi4 ; jump if not '0' to '9' cmp al,'9' ja atoi4 ; jump if not '0' to '9' and ax,0fh ; isolate lower four bits xchg bx,ax ; multiply answer x 10 mov dx,10 mul dx add bx,ax ; add this digit jmp atoi2 ; convert next digit atoi4: mov ax,bx ; result into AX jcxz atoi5 ; jump if sign flag clear neg ax ; make result negative atoi5: pop dx ; restore registers pop cx pop bx ret ; back to caller atoi endp code ends end start