;======================================================
;Code that determines whether a command line
;was present or not.  Have a look and see how it works
;The program segment prefix (PSP) contains information
;about the program  including the number or characters
;in the command tail at 80h and the command tail
;which begins at 81h and is 127 bytes long.
;This shows how to read the command trail and remove
;spaces you may not need.
;======================================================

.MODEL SMALL        ;Set small memory model
.8086	       ; Use crusty 8086 code
.STACK
.DATA
FILENAME	DB	13 DUP (?)
NOCLINE 	DB	"Enter a command line paramater.",0ah,0dh,"e.g: TEST7 Hello!",0ah,0dh,24h
YOUTYPED        DB      "The command line you entered was : ",24H
.CODE

MAIN	PROC	NEAR

	MOV	AX,@DATA
	MOV	DS,AX
        PUSH    DS      ;Make ES point to data segment
        PUSH    ES      ;and DS to PSP.  ES is set to PSP
        POP     DS      ;on program entry.
        POP     ES      ;The need to be swapped for the commands we are going to use
        ;ES:[DI] Points to filename variable
        ;and DS:[SI] points to PSP, need to be like this for STOSB and LODSB
        ;command

	LEA	DI,FILENAME
	CLD
	XOR	CH,CH
	MOV	SI,80H
        MOV     CL,[SI]
	TEST	CL,CL
	JNZ	XD1
	PUSH	DS
	PUSH	ES
	POP	DS
        POP     ES    ;Put ES and DS back to normal;
	MOV	DX,OFFSET NOCLINE
	MOV	AH,09H
	INT	21H
	MOV	AX,4C01H
	INT	21H
XD1:
	INC	SI
X1:	LODSB
	CMP	AL,' '	   ;Was it a space?
	JE	X4		   ;Yes, so skip it
	STOSB		   ;Store a byte
X4:	LOOP	X1		   ;Keep going to the end
	MOV	AL,24H
        STOSB              ;Make sure '$' at end of path

	PUSH	DS
	PUSH	ES
	POP	DS
        POP     ES    ;Put ES and DS back to normal;

        MOV     DX,OFFSET YOUTYPED
	MOV	AH,09H
	INT	21H
        MOV     DX,OFFSET FILENAME
	INT	21H

	MOV	AX,4C00H	 ; Send exit code to dos
	INT     21H             ; Send command to DOS
MAIN          ENDP                    ; Set end of program
	END            MAIN                   ; Set starting address!
					; Hard to explain. Read the book.