Calculator assembly language based on 51 single chip microcomputer

The calculators we talked about before were all based on C language. Next, let’s talk about a simple calculator based on assembly language.

hardware design

The display is still a digital tube, and the MCU is C51, which supports integer calculation.

Simulation diagram:

programming

YJ EQU 50H ;Result storage

YJ1 EQU 51H ;Intermediate result storage

GONG EQU 52H ; Function key storage

          ORG 0000H

START: MOV R3,#0 ; Initialization display is empty

          MOV GONG,#0      

          MOV 32H,#00H

          MOV 33H,#00H

          MOV 34H,#00H

MLOOP: CALL DISP ;Call display subroutine

WAIT: CALL TESTKEY ; Check if a key is pressed

          JZ WAIT ; Check if the accumulator is 0 

          CALL GETKEY ; read key

          INC R3 ;Number of buttons

          CJNE A,#0,NEXT1 ; Determine whether it is a numeric key

          LJMP E1 ; Switch to numeric key processing

NEXT1: CJNE A,#1,NEXT2

          LJMP E1

NEXT2: CJNE A,#2,NEXT3

          LJMP E1

NEXT3: CJNE A,#3,NEXT4

          LJMP E1

NEXT4: CJNE A,#4,NEXT5

          LJMP E1

NEXT5: CJNE A,#5,NEXT6

          LJMP E1

NEXT6: CJNE A,#6,NEXT7

          LJMP E1

NEXT7: CJNE A,#7,NEXT8

          LJMP E1

NEXT8: CJNE A,#8,NEXT9

          LJMP E1

NEXT9: CJNE A,#9,NEXT10

          LJMP E1

NEXT10: CJNE A,#10,NEXT11; Determine whether it is a function key

          LJMP E2 ; Switch to function key processing

NEXT11: CJNE A,#11,NEXT12

          LJMP E2

NEXT12: CJNE A,#12, NEXT13

          LJMP E2

NEXT13: CJNE A,#13,NEXT14

          LJMP E2

NEXT14: CJNE A,#14,NEXT15

          LJMP E2

NEXT15: LJMP E3; Determine whether to clear the key

E1: CJNE R3,#1,N1; Determine which key is pressed

          LJMP E11 ; for the first number

N1: CJNE R3,#2,N2

          LJMP E12; for the second number

N2: CJNE R3,#3,N3

          LJMP E13 ; for the third digit

N3: LJMP E3; The fourth digit overflows

E11: MOV R4,A; Input value is temporarily stored in R4

          MOV 34H,A ; input value is sent to display buffer

          MOV 33H,#00H

          MOV 32H,#00H

          LJMP MLOOP ; Wait for input again

E12: MOV R7,A; single digit is temporarily stored in R7

          MOV B,#10

          MOV A,R4

          MUL AB ; Tens digit

          ADD A,R7

          MOV R4,A ; input value stored in R4

          MOV 32H,#00H ; Input value is sent to display buffer

          MOV 33H,34H

          MOV 34H,R7

          LJMP MLOOP ; Wait for input again

E13: MOV R7,A

          MOV B,#10

          MOV A,R4

          MUL AB

          JB OV,E3; Input overflow, if OV is equal to 1, go to E3

          ADD A,R7

          JB CY,E3 ; Input overflow

          MOV R4,A

          MOV 32H,33H ; input value to display buffer

          MOV 33H,34H

          MOV 34H,R7

          LJMP MLOOP

E3: MOV R3,#0 ; reset the number of key presses

          MOV R4,#0 ; input value cleared

          MOV YJ,#0 ; Clear the calculation result

          MOV GONG,#0 ; Set the function key to zero      

          MOV 32H,#00H ; Display clear

          MOV 33H,#00H

          MOV 34H,#00H

          LJMP MLOOP

E2: MOV 34H,#00H

           MOV 33H,#00H

           MOV 32H,#00H

           MOV R0,GONG ;Exchange with the last function key

           MOV GONG,A

           MOV A,R0

           CJNE A,#10,N21 ;Judgement function key

           LJMP JIA ;"＋"

N21: CJNE A,#11,N22

           LJMP JIAN ;"－"

N22: CJNE A,#12,N23

           LJMP CHENG ;"*"

N23: CJNE A,#13,N24

           LJMP CHU ;"/"

N24: CJNE A,#0,N25

           LJMP FIRST ; Press the function key for the first time

N25: LJMP DEN ;"="

N4: LJMP E3

FIRST: MOV YJ,R4; input value to result

           MOV R3,#0 ; reset the number of key presses

           LJMP DISP1 ; Result processing

JIA: MOV A,YJ ; send the last result to the accumulator

           ADD A,R4; last result plus input value

           JB CY,N4 ;Overflow

           MOV YJ,A ; store this result

           MOV R3,#0 ; reset the number of key presses

           LJMP DISP1

JIAN: MOV A,YJ

           SUBB A, R4 ; Last result minus input value

           JB CY,N4 ; Negative overflow

           MOV YJ,A

           MOV R3,#0

           LJMP DISP1

CHENG: MOV A,YJ

           MOV B,A

           MOV A,R4

           MUL AB ; last result multiplied by input value

           JB OV,N4 ;Overflow

           MOV YJ,A                 

           LJMP DISP1

CHU: MOV A,R4

           MOV B,A

           MOV A,YJ

           DIV AB ; divide the last result by the input value

           MOV YJ,A

           MOV R3,#0

           LJMP DISP1

DEN: MOV R3,#0

           LJMP DISP1

DISP1: MOV B,#10

           MOV A,YJ ; send the result to the accumulator

           DIV AB ; Divide the result by 10

           MOV YJ1,A ; Temporarily store "商"

           MOV A,B ; take the unit digit

           MOV 34H,A ; Send the single digit to the display buffer

           MOV A,YJ1

           JZ DISP11 ; Is the result a single digit?

           MOV B,#10

           MOV A,YJ1

           DIV AB

           MOV YJ1,A

           MOV A,B

           MOV 33H,A ; Send the ten digits to the display buffer

           MOV A,YJ1

           JZ DISP11 ; Is the result a two-digit number?

           MOV 32H,A ; send the hundreds digit to the display buffer

DISP11: LJMP MLOOP

The file is for reference only:

Link: https://pan.baidu.com/s/1ZAxAbTe_oD_cuTvvKWxU5A

Extraction code: x102