2013-09-09: Read two strings and check whether one of them is a subtring of other or not

DISPSTR.asm

DISP_STR PROC

	SAVE_REG <AX, CX, DX, SI>
	MOV CX, BX
	CLD
	MOV AH, 2
    DISP_LOOP:
	LODSB
	MOV DL, AL
	INT 21H
    LOOP DISP_LOOP
	LOAD_REG <SI, DX, CX, AX>
    RET

DISP_STR ENDP

prog.asm

TITLE Assignment: Read two strings and check whether one is a substring of other
 
.MODEL SMALL
 
	SAVE_REG MACRO REGS
		IRP D, <REGS>
			PUSH D
		ENDM
	ENDM
	LOAD_REG MACRO REGS
		IRP D, <REGS>
			POP D
		ENDM
	ENDM
	END_DOS MACRO
		MOV AH, 76
		INT 21H
	ENDM
	NEWLINE MACRO
		SAVE_REG <AX, DX>
		MOV AH, 2
		MOV DL, 0AH
		INT 21H
		MOV DL, 0DH
		INT 21H
		LOAD_REG <DX, AX>
	ENDM
 
.STACK 100H
 
.DATA
 
	STR1 DB 200 DUP(65)
	STR2 DB 200 DUP(0)
	PROMPT DB "Enter string "
	NUM DB "1: $"
	L1 DW 0
	UNEQL DB "No substring found$"
	EQUAL DB "Substring was found$"
.CODE
 
MAIN PROC
 
	MOV AX, @DATA
	MOV DS, AX
	MOV ES, AX
	MOV AH, 9
	LEA DX, PROMPT
	INT 21H
	LEA DI, STR1
	CALL READ_STR
	MOV L1, BX
	NEWLINE
	MOV NUM, '2'
	INT 21H
	LEA DI, STR2
	CALL READ_STR
	LEA SI, STR1
	LEA DI, STR2		; DI stores the longer string
	CMP L1, BX
      JE EQL
	CMP L1, BX
      JG INV
	MOV CX, BX
	SUB CX, L1
    JMP COMPARE
    INV:
	MOV CX, L1
	SUB CX, BX
	MOV L1, BX
	LEA SI, STR2
	LEA DI, STR1		; DI stores longer string
	NEWLINE
	CALL DISP_STR
    JMP COMPARE
    EQL:
	MOV CX, 1
    COMPARE:
	XOR DX, DX
    TOP:
	SAVE_REG <DI, SI>
	ADD DI, DX
	PUSH CX
	MOV CX, L1
	REPE CMPSB
      JE FOUND
	INC DX
	POP CX
	LOAD_REG <SI, DI>
    LOOP TOP
    NOT_FOUND:
	NEWLINE
	LEA DX, UNEQL
	MOV AH, 9
	INT 21H
	END_DOS
    FOUND:
	POP CX
	LOAD_REG <SI, DI>
	NEWLINE
	LEA DX, EQUAL
	MOV AH, 9
	INT 21H
	END_DOS
 
MAIN ENDP
 
	INCLUDE READSTR.ASM
	INCLUDE DISPSTR.ASM
 
END MAIN

READSTR.asm

READ_STR PROC

	SAVE_REG <AX, DI>
	XOR BX, BX
	CLD
	MOV AH, 1
	INT 21H
    WHILE_LOOP:
	CMP AL, 0DH
      JE END_WHILE
	CMP AL, 08H
      JNE STORAGE
	DEC BX
	DEC DI
    JMP NEXT
    STORAGE:
	STOSB
	INC BX
    NEXT:
	INT 21H
    JMP WHILE_LOOP
    END_WHILE:
	LOAD_REG <DI, AX>
    RET

READ_STR ENDP