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Assembly Source File | 1993-03-31 | 20.7 KB | 462 lines

;**************************************************************************** ; CMOSSAVE saves the contents of CMOS RAM to a file. Its syntax is: ; ; CMOSSAVE [d:][path]filename [/nnn] ; ; where "filename" is the name of the file to which CMOS data will be ; saved, and "nnn" specifies the number of bytes to save. Valid values ; for "nnn" are 64 to 256. If the /nnn switch is omitted, CMOSSAVE ; determines how many bytes of CMOS your PC contains and saves them all. ; Use CMOSRSTR to restore CMOS RAM data. ;**************************************************************************** CMOS_ADDR equ 70h ;CMOS address port CMOS_DATA equ 71h ;CMOS data port code segment assume cs:code,ds:code org 100h begin: jmp main copyright db "CMOSSAVE 2.0 Copyright (c) 1993 Jeff Prosise",13,10 db "From: PC Magazine DOS 6 Memory Management " db "with Utilities",13,10,13,10,"$" helpmsg db "Saves the configuration data stored in CMOS RAM to " db "a file.",13,10,13,10 db "CMOSSAVE [d:][path]filename [/nnn]",13,10,13,10 db " filename Name of the file to which configuration " db "data will be saved.",13,10 db " /nnn Number of bytes of CMOS RAM to save." db 13,10,13,10 db "Use CMOSRSTR to restore CMOS configuration data." crlf db 13,10,"$" errmsg1 db "Syntax: CMOSSAVE [d:][path]filename [/nnn]",13,10,"$" errmsg2 db "The file already exists. Replace it (Y/N)? $" errmsg3 db "Invalid path or file name. File could not be " db "created.",13,10,"$" errmsg4 db "Error writing file to disk",13,10,"$" errmsg5 db "Disk full",13,10,"$" errmsg6 db "Invalid numeric parameter or value out of range" db 13,10,"$" msg db " bytes were copied from CMOS RAM to disk",13,10,"$" handle dw ? ;File handle filename dw 0 ;Address of file name cmoslength dw ? ;Number of bytes to save nnn dw 0 ;Value of "nnn" parameter ;**************************************************************************** ; Procedure MAIN ;**************************************************************************** main proc near cld ;Clear direction flag mov si,81h ;Point SI to command line call scanhelp ;Scan for "/?" switch jnc main1 ;Branch if not found mov ah,09h ;Display help text and exit mov dx,offset helpmsg ;with ERRORLEVEL=0 int 21h mov ax,4C00h int 21h ; ; Parse the command line. ; main1: call findchar ;Find a parameter jc main2 ;Branch if end of line cmp byte ptr [si],"/" ;Branch if the parameter je main1a ;starts with a "/" mov filename,si ;Save the address call finddelim ;Find the end of the string mov byte ptr [si],0 ;Convert file name to ASCIIZ jc main2 ;Branch if end of line inc si ;Advance SI jmp main1 ;Loop back for more main1a: inc si ;Skip the "/" character call asc2bin ;Read and convert the number mov dx,offset errmsg6 ;Error if carry returns set jc error cmp ax,64 ;Error if number is less jb error ;than 64 or greater than cmp ax,256 ;256 ja error mov nnn,ax ;Save the value jmp main1 ;Loop back for more main2: cmp filename,0 ;Branch if a file name jne main2a ;was entered mov dx,offset errmsg1 ;Point DX to error message error: mov ah,09h ;Display error message int 21h error_exit: mov ax,4C01h ;Exit with ERRORLEVEL=1 int 21h main2a: mov cx,nnn ;Set CMOSLENGTH equal to mov cmoslength,cx ;NNN and branch if a number or cx,cx ;was entered on the command jnz main3 ;line call getlength ;Get CMOS length mov cmoslength,cx ;Save the result ; ; Create the data file. ; main3: mov ax,3D00h ;Attempt to open the file mov dx,filename ;with DOS function 3Dh int 21h jc main4 ;Branch if the call failed mov bx,ax ;Close the file mov ah,3Eh int 21h mov ah,09h ;Ask if user wants to mov dx,offset errmsg2 ;overwrite it int 21h ask: mov ah,08h ;Get the response int 21h or al,al jnz compare mov ah,08h int 21h jmp ask compare: cmp al,"Y" ;Ask again if the answer je yes ;isn't "Y" or "N" cmp al,"y" je yes cmp al,"N" je no cmp al,"n" jne ask no: mov ah,02h ;Display "N" and abort mov dl,"N" int 21h mov ah,09h mov dx,offset crlf int 21h jmp error_exit yes: mov ah,02h ;Display "Y" and continue mov dl,"Y" int 21h mov ah,09h mov dx,offset crlf int 21h main4: mov ah,3Ch ;Create the file by calling xor cx,cx ;DOS function 3Ch mov dx,filename int 21h mov dx,offset errmsg3 ;Error if the file could jc main6a ;not be created mov handle,ax ;Save the file handle ; ; Read the configuration data from CMOS RAM, compute the checksum, and ; write both to the file. ; mov cx,8 ;Copy the CMOSSAVE signature mov si,offset copyright ;to the output buffer mov di,offset scanhelp rep movsb cld ;Clear direction flag xor cx,cx ;Initialize counter main5: mov al,cl ;Get address in AL cli ;Interrupts off out CMOS_ADDR,al ;Output CMOS address jmp short $+2 ;I/O delay jmp short $+2 in al,CMOS_DATA ;Read one byte of CMOS data stosb ;Buffer the byte sti ;Interrupts on inc cx ;Increment counter cmp cx,cmoslength ;Loop if there are more jne main5 ;bytes to save xor al,al ;Compute the checksum mov cx,cmoslength add cx,8 mov si,offset scanhelp main6: add al,[si] inc si loop main6 stosb ;Copy checksum to buffer mov ah,40h ;Write the data to the file mov bx,handle mov cx,cmoslength add cx,9 mov dx,offset scanhelp int 21h mov dx,offset errmsg4 jc main6a ;Branch on error cmp ax,cx ;Error if the disk is je main7 ;full mov dx,offset errmsg5 main6a: jmp error ; ; Close the file, display message, and exit. ; main7: mov ah,3Eh ;Close the data file mov bx,handle int 21h mov ah,09h ;Display copyright message mov dx,offset copyright int 21h mov ax,cmoslength ;Display the number of call bin2asc ;bytes that were saved mov ah,09h mov dx,offset msg int 21h mov ax,4C00h ;Exit with ERRORLEVEL=0 int 21h main endp ;**************************************************************************** ; GETLENGTH returns the number of bytes of CMOS RAM that this PC ; contains in CX. GETLENGTH will never return a value less than 64 ; or greater than 256. ;**************************************************************************** getlength proc near mov cx,64 ;Initialize counter gl_loop: cli ;Interrupts off mov al,cl ;Get address in AL out CMOS_ADDR,al ;Output CMOS address jmp short $+2 ;I/O delay jmp short $+2 in al,CMOS_DATA ;Read one byte of CMOS data mov bl,al ;Save the byte in BL sti ;Interrupts on mov al,0A5h ;Test this byte with call testbyte ;alternating 1s and 0s jc gl_exit mov al,5Ah ;Test this byte with call testbyte ;alternating 0s and 1s jc gl_exit mov al,00h ;Test this byte with call testbyte ;all 0s jc gl_exit mov al,0FFh ;Test this byte with call testbyte ;all 1s jc gl_exit cli ;Interrupts off mov al,cl ;Get address in AL out CMOS_ADDR,al ;Output CMOS address jmp short $+2 ;I/O delay jmp short $+2 mov al,bl ;Get original value in AL out CMOS_DATA,al ;Restore the byte sti ;Interrupts on inc cx ;Increment counter cmp cx,256 ;Loop back for more if jne gl_loop ;CX is less than 256 mov al,80h ;Make sure NMI is enabled out CMOS_ADDR,al ;if this happens to be a jmp short $+2 ;PS/2 jmp short $+2 in al,CMOS_DATA gl_exit: ret ;Return to caller getlength endp ;**************************************************************************** ; TESTBYTE tests a byte of CMOS RAM to see if it really does contain RAM. ; On entry, CL holds the CMOS address. On return, carry is clear if the ; byte contains RAM, set if it does not. ;**************************************************************************** testbyte proc near mov ah,al ;Save test value in AH cli ;Interrupts off mov al,cl ;Get address in AL out CMOS_ADDR,al ;Output CMOS address jmp short $+2 ;I/O delay jmp short $+2 mov al,ah ;Get test value in AL out CMOS_DATA,al ;Output the test value jmp short $+2 ;I/O delay jmp short $+2 mov al,cl ;Get address in AL out CMOS_ADDR,al ;Output CMOS address jmp short $+2 ;I/O delay jmp short $+2 in al,CMOS_DATA ;Read the test value back sti ;Interrupts on cmp al,ah ;Compare the values je tb_exit ;Branch if they're equal stc ;Set carry and return ret tb_exit: clc ;Clear carry and return ret testbyte endp ;**************************************************************************** ; ASC2BIN converts the text pointed to by SI to a number and returns the ; value in AX. Carry returns set if the text contains an invalid character ; or if an overflow error occurred. ;**************************************************************************** asc2bin proc near cld ;Clear direction flag sub ax,ax ;Initialize registers xor bh,bh mov cx,10 a2b_loop: mov bl,[si] ;Get a character inc si cmp bl,20h ;Exit if space je a2b_exit cmp bl,09h ;Exit if tab je a2b_exit cmp bl,2Ch ;Exit if comma je a2b_exit cmp bl,0Dh ;Exit if carriage return je a2b_exit cmp bl,"0" ;Error if character is not jb a2b_error ;a number cmp bl,"9" ja a2b_error mul cx ;Multiply the value in AX jc a2b_error ;by 10 and exit on overflow sub bl,30h ;ASCII => binary add ax,bx ;Add latest value to AX jnc a2b_loop ;Loop back if no overflow a2b_error: dec si ;Set carry and exit stc ret a2b_exit: dec si ;Clear carry and exit clc ret asc2bin endp ;**************************************************************************** ; BIN2ASC converts a binary value in AX to ASCII form and displays it. ;**************************************************************************** bin2asc proc near mov bx,10 ;Initialize divisor word and xor cx,cx ;digit counter b2a1: inc cx ;Increment digit count xor dx,dx ;Divide by 10 div bx push dx ;Save remainder on stack or ax,ax ;Loop until quotient is zero jnz b2a1 b2a2: pop dx ;Retrieve a digit from stack add dl,30h ;Convert it to ASCII mov ah,2 ;Display it int 21h loop b2a2 ;Loop until done ret bin2asc endp ;**************************************************************************** ; SCANHELP scans the command line for a /? switch. If found, carry returns ; set and SI contains its offset. If not found, carry returns clear. ;**************************************************************************** scanhelp proc near push si ;Save SI scanloop: lodsb ;Get a character cmp al,0Dh ;Exit if end of line je scan_exit cmp al,"?" ;Loop if not "?" jne scanloop cmp byte ptr [si-2],"/" ;Loop if not "/" jne scanloop add sp,2 ;Clear the stack sub si,2 ;Adjust SI stc ;Set carry and exit ret scan_exit: pop si ;Restore SI clc ;Clear carry and exit ret scanhelp endp ;**************************************************************************** ; FINDCHAR advances SI to the next non-white-space character. On return, ; carry set indicates EOL was encountered; carry clear indicates it was not. ;**************************************************************************** findchar proc near lodsb ;Get the next character cmp al,09h ;Loop if tab je findchar cmp al,20h ;Loop if space je findchar cmp al,2Ch ;Loop if comma je findchar dec si ;Point SI to the character cmp al,0Dh ;Exit with carry set if end je eol ;of line is reached clc ;Clear carry and exit ret eol: stc ;Set carry and exit ret findchar endp ;**************************************************************************** ; FINDDELIM advances SI to the next white-space character. On return, ; carry set indicates EOL was encountered. ;**************************************************************************** finddelim proc near lodsb ;Get the next character cmp al,09h ;Exit if tab je fd_exit cmp al,20h ;Exit if space je fd_exit cmp al,2Ch ;Exit if comma je fd_exit cmp al,0Dh ;Loop back for more if end jne finddelim ;of line isn't reached dec si ;Set carry and exit stc ret fd_exit: dec si ;Clear carry and exit clc ret finddelim endp code ends end begin