DATA      SEGMENT

EXPRESS   DW 40 DUP(?)

TEMP      DW 0

RESULT    DD 0

ASSIST    DD 0

BUF       DB 0AH,0DH,'Input invalid,Try again'

DATA      ENDS

CODE      SEGMENT

          ASSUME CS:CODE,DS:DATA

MAIN      PROC   FAR

START:    MOV    AX,DATA

          MOV    DS,AX

          CALL   GETINPUT

          CALL   MYCAL

          CALL   DISPLAY

          MOV    AH,4CH

          INT    21H

MAIN      ENDP

GETINPUT  PROC   NEAR

          LEA    DI,EXPRESS

          MOV    AX,0H

          PUSH   AX

S_TART:   AND    AX,0

          AND    BX,0

          AND    CX,0

          MOV    AH,01H

          INT    21H

L1:       CMP    AL,'0'

          JB     L2

          CMP    AL,'9'

          JA     L2

S:        AND    AX,000FH

          MOV    CX,AX

          CALL   GETNUM

L2:       CMP    AL,'='

          JNZ    L3

ONE:      MOV    CX,0

          POP    CX

          AND    CX,00FFH

          CMP    CX,0H

          JZ     ZERO

          MOV   [DI],CX

          ADD    DI,2

          JMP    ONE

ZERO:     AND    AX,00FFH

          MOV   [DI],AX

          ADD    DI,2H

          RET

L3:       CMP    AL,'('

          JNZ    L4

          PUSH   AX

          JMP    S_TART

L4:       CMP    AL,')'

          JNZ    L5

S1:       POP    CX

          AND    CX,00FFH

          CMP    CL,'('

          JZ     S_TART

          CMP    CX,0

          JNZ    AS

          PUSH   CX

          JMP    S_TART

AS:       MOV    [DI],CX

          ADD    DI,2

          JMP    S1

L5:       CMP    AL,'*'

          JZ     L6

          CMP    AL,'/'

          JZ     L6

          JMP    L7

L6:       POP    CX

          AND    CX,00FFH

          CMP    CL,'*'

          JZ     C1

          CMP    CL,'/'

          JZ     C1

          PUSH   CX

          PUSH   AX

          JMP    S_TART

C1:       MOV    [DI],CX

          ADD    DI,2

          PUSH   AX

          JMP    S_TART

L7:       CMP    AL,'+'

          JZ     L8

          CMP    AL,'-'

          JZ     L8

          JMP    L9

L8:       POP    CX

          AND    CX,00FFH

          CMP    CX,'('

          JZ     D1

          CMP    CX, 0

          JZ     D1

          MOV   [DI],CX

          ADD    DI,2

          PUSH   AX

          JMP    S_TART

D1:       PUSH   CX

          PUSH   AX

          JMP    S_TART

L9:       MOV    CX,15

          LEA    BX,BUF

V1:       MOV    DL,[BX]

          INC    BX

          MOV    AH,02H

          INT    21H

          LOOP   V1

          RET

GETINPUT  ENDP



GETNUM    PROC   NEAR

          PUSH   BX

NUM_STAR: MOV    AH,01H

          INT    21H

          CMP    AL,30H

          JC     NUM_OUT

          CMP    AL,3AH

          JNC    NUM_OUT

          ADD    CX,CX

          MOV    BX,CX

          ADD    CX,CX

          ADD    CX,CX

          ADD    CX,BX

          AND    AX,000FH

          ADD    CX,AX

          JMP    NUM_STAR    

NUM_OUT:  MOV   [DI],CX

          ADD    DI,2

          POP    BX

          RET

GETNUM    ENDP



MYCAL     PROC   NEAR

          LEA    SI,RESULT

          LEA    DI,ASSIST

          LEA    BX,EXPRESS

CAL_STAR: AND    DX,0

          AND    AX,0

          CMP   [BX],'*'

          JZ     CAL_MUL

          CMP   [BX],'/'

          JZ     CAL_DIV

          CMP   [BX],'+'

          JZ     CAL_ADD

          CMP   [BX],'-'

          JZ     CAL_SUB

          CMP   [BX],'='

          JZ     CAL_OUT

          PUSH   WORD PTR [BX]

          ADD    BX,2

          JMP    CAL_STAR

CAL_MUL:  POP    DX

          POP    AX

          IMUL   DX

          PUSH   AX

          ADD    BX,2

          JMP    CAL_STAR

CAL_DIV:  POP    DX

          POP    AX

          IDIV   DL

          PUSH   AX

          ADD    BX,2

          JMP    CAL_STAR

CAL_ADD:  POP    DX

          POP    AX

          ADC    AX,DX

          PUSH   AX

          ADD    BX,2

          JMP    CAL_STAR

CAL_SUB:  POP    DX

          POP    AX

          SBB    AX,DX

          PUSH   AX

          ADD    BX,2

          JMP    CAL_STAR

CAL_OUT:  POP    CX

          RET

MYCAL     ENDP



DISPLAY   PROC   NEAR

          CMP    CX,10000

          JNC    AA12

          CMP    CX,1000

          JNC    AA4

          CMP    CX,100

          JNC    AA6

          CMP    CX,10

          JNC    AA8

          JMP    AA10

AA12:     MOV    DL,-1

AA3:      SUB    CX,10000

          INC    DL

          JNC    AA3

          ADD    CX,10000

          OR     DL,30H

          MOV    AH,2H

          INT    21H

AA4:      MOV    DL,-1

AA5:      SUB    CX,1000

          INC    DL

          JNC    AA5

          ADD    CX,1000

          OR     DL,30H

          MOV    AH,2H

          INT    21H

AA6:      MOV    DL,-1

AA7:      SUB    CX,100

          INC    DL

          JNC    AA7

          ADD    CX,100

          OR     DL,30H

          MOV    AH,2H

          INT    21H

AA8:      MOV    DL,-1

AA9:      SUB    CX,10

          INC    DL

          JNC    AA9

          ADD    CX,10

          OR     DL,30H

          MOV    AH,2H

          INT    21H

AA10:     MOV    DL,CL

          OR     DL,30H

          MOV    AH,2H

          INT    21H

          RET

DISPLAY   ENDP



CODE      ENDS

          END START