sseg segment stack
db 128 dup (0)
sseg ends
dseg segment para public 'global'
extrn parambuf:byte
extrn paramnr:word
configpath db 'config.txt',0 ; file name to be open
dseg ends
cseg segment para public 'code'
assume cs:cseg,ds:dseg,ss:sseg
public rdconfig,chksynx
extrn panic:near
rdconfig proc near
push ds ; save caller's segment
push es
push bp ; make stack frame
mov bp,sp
mov ax,3d00h ; read only open file
mov dx,offset configpath
int 21h
jnc suc
; don't clear carry if error detected
mov sp,bp
pop bp ; restore stack frame
pop es
pop ds
ret ; leave error code in ax
suc:
mov bx,ax ;we will read the config file
xor ax,ax
mov ah,3fh
mov dx,offset parambuf
mov cx,1024
int 21h
jnc suc1
mov sp,bp
pop bp
pop es
pop ds
ret
suc1:
mov [paramnr],ax ; indicate how many byte we read from config file
clc ; guaratee no error
; the file handler is already set properly
mov ah,3eh
int 21h ; close config file
; we don't care if this operating is successful
mov sp,bp
pop bp
pop es
pop ds
ret
rdconfig endp
chksynx proc near
push ds
push es
push bp
mov bp,sp
sub sp,4
; stack arranges like this
; [bp-2] : first '/' char position
; [bp-4] : first '$' char position
; try to find the '#', if '#' not present in our parameter
; buf, we will refuse to continue operating and panic
cmp word ptr [paramnr],0 ; configuration file can't be NULL
jne cnext1
mov ax,105
push ax
call panic
cnext1:
cld ; clear direction
mov di,offset parambuf
mov cx,[paramnr]
mov al,35 ; '#'
repnz scasb ; find first '#' char
jz found1
mov ax,100 ; get appropriate error code
push ax
call panic
found1:
; '/' should be first encounted
cld ; clear direction
mov di,offset parambuf
mov cx,[paramnr]
mov al,47 ; '/'
repnz scasb ; find first '/' char
jz found2
mov ax,106
push ax
call panic
found2:
mov [bp-2],di ; save position of '/'
cld ; clear direction
mov di,offset parambuf
mov cx,[paramnr]
mov al,36 ; '$'
repnz scasb ; find first '$' char
jz found3
mov ax,106
push ax
call panic
found3:
mov [bp-4],di
cmp [bp-2],di ; who is big?
jb right
mov ax,106
push ax
call panic
right:
mov sp,bp
pop bp
pop es
pop ds
ret
chksynx endp
cseg ends
end
