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OPARSCMD.ASM
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Assembly Source File
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1989-05-02
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3KB
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104 lines
; FILENAME: OPARSCMD.ASM
; Copyright (c) 1988, 1989 by Borland International, Inc.
;
; Description: This module implements the routine ParseCmd. ParseCmd
; parses the command line.
;
; ASSEMBLY INSTRUCTIONS: To assemble this module use the following
; TASM command line.
;
; TASM oparscmd
include globals.inc
_TEXT segment
ParseCmd proc
; Input
; si - address of start of command line
; OptTab - Option Table
; Options - designates user set options
; Output
; command line processed
; Registers modified
; si, bx, ax, di
push ds ;save current value of ds
push ds ;set es to point to current
pop es ;data segment
mov ax, PSP ;set ds to point to the PSP
mov ds, ax
mov si, 80h ;command tail
lea di, CMDBUF ;get the address of the local buffer
mov cx, BUFLEN ;get the size of the local buffer
rep movsb ;get a copy of the command-line arguments
pop ds ;reset ds to the data segment
lea si, CMDBUF ;load si with the address of CMDBUF for the
;lodsb instruction
lodsb ;get number of bytes
cmp al, 0 ;see if command tail exists
jnz hastail
mov al, '?' ;force help screen
jmp SHORT parcmd1a
hastail:
mov bx, si
sub ah, ah
add bx, ax ;BX points to end
parcmd1:
cmp bx, si ;check if done
je parcmd5
lodsb ;get character
parcmd1a:
mov mess1+16, al ;put in message in case of error
lea di, OptTab ;start of table
parcmd2:
cmp BYTE PTR [di], 0 ;check if end of table
je parcmd6
cmp al, [di] ;check if option matches
je parcmd3
add di, 5 ;skip to next entry
jmp parcmd2
;--- found matching option
parcmd3:
mov ax, [di+1] ;load command word
or ax, ax ;check if branch location
jnz parcmd4
mov ax, [di+3] ;load option flag
xor Options, ax ;flip bits
jmp parcmd1
parcmd4:
call ax ;branch to special routine
jmp parcmd1
;--- finished
parcmd5:
ret
;--- bad option
parcmd6:
mov al, 0 ;error number
call ErrorExit ;call error routine
ParseCmd endp
_TEXT ends
end