404

; Example of finding an environmental variable in the environment string


	jmp start      

errmess: db 'Not found$'

env_var: db 'PATH=',0
env_val: db 128 dup 0

start:
        mov si,0 

	push es
	mov es,ds
	push ds
	mov ds,W[02C]			;Fetch the environment


one_more:
	es mov di,env_var 

l1:
	cmpsb
	je l1

	sub si,1
	es cmp di,env_val              ; All characters match?

	je  getval                     ; Yes, fetch value of variable

nxtch:
	inc si                          ; Find next variable in string
	ds cmp b[si],0
	jne nxtch
        inc si
	ds cmp b[si],0			; End of Environment string?
	jne one_more                    ; No, check the variable

	pop ds
	pop es

	mov ah,09H
	mov dx,errmess
	int 21H

	mov ax,04c00	
	int 21H

	
getval:                                 ; Get contents of variable
	movsb	
	cmp b[si-1],0
	jne getval	

	es mov b[di],'$'

	pop ds
	pop es
	

	mov ah,09H
	mov dx,env_val
	int 21H

	mov ax,04c00
	int 21H

c_end:
.

0