#TJHSST ~ Misc assembly programs from "Computer Architecture" class

xlat.asm

;-----------------------------------------------------------------------;
;       XLAT and XLATB                                                  ;
;               What are they?                                          ;
;-----------------------------------------------------------------------;
        .MODEL  SMALL
        .STACK                  ; Allocate space for a stack, 1K
        .DATA
DIGIT_TABLE     DB      '0123456789ABCDEF'      ; Hex digit table
JUMP_TABLE      DB      1       ; Table of jumps, array of pointers
                DB      9       ; They folow the sequence
                DB      3       ; 1,2,3,4,5,6,7,8,9,0,1,2,...
                DB      7
                DB      5
                DB      4
                DB      6
                DB      8
                DB      2
                DB      8
        .CODE
;-----------------------------------------------------------------------;
;               WRITE_HEX_DIGIT                                         ;
;       Entry:  DL      Hex digit to print out                          ;
;       Effect:         Prints out the digit                            ;
;       Return:         Nothing                                         ;
;-----------------------------------------------------------------------;
WRITE_HEX_DIGIT PROC
        PUSH    AX              ; Save AX and BX
        PUSH    BX
        MOV     AL,DL           ; Make DL an address into a table
        MOV     BX,OFFSET DIGIT_TABLE   ; Set DS:BX up for the XLAT
        XLATB                   ; Load character into AL
        MOV     DL,AL           ; Restore DL
        MOV     AH,2h           ; Print character function
        INT     21h
        POP     BX              ; Restore BX and AX
        POP     AX
        RET
WRITE_HEX_DIGIT ENDP

;-----------------------------------------------------------------------;
START_HERE:
        MOV     AX,@DATA
        MOV     DS,AX
        MOV     BX,OFFSET JUMP_TABLE
        MOV     AL,0
        MOV     CX,70
;-----------------------------------------------------------------------;
POINTER_LOOP:                   ; Loop the print out procedure
        XLATB
        MOV     DL,AL
        CALL    WRITE_HEX_DIGIT ; Actually print out the hex digit.
        LOOP    POINTER_LOOP
;-----------------------------------------------------------------------;
        MOV     AH,04Ch
        INT     21h
        END     START_HERE
;-----------------------------------------------------------------------;

xlat2.asm

;-----------------------------------------------------------------------;
;       XLAT and XLATB                                                  ;
;               What are they?                                          ;
;       Part II                                                         ;
;-----------------------------------------------------------------------;
        .MODEL  SMALL
        .STACK                  ; Allocate space for a stack, 1K
        .DATA
GREETINGS       DB      'Enter a number from 1 to 5, 0 quits',13,10,'$'
BASE_STR        DB      'Function # ','$'
END_STR         DB      13,10,'$'
NUMBERS         DB      '0123456789'
JUMP_TABLE      DB      OFFSET FUNCTION0        ; The table of jumps
                DB      OFFSET FUNCTION1
                DB      OFFSET FUNCTION2
                DB      OFFSET FUNCTION3
                DB      OFFSET FUNCTION4
                DB      OFFSET FUNCTION5
        .CODE
;-----------------------------------------------------------------------;
;               WRITE_DIGIT                                             ;
;       Entry:  DL      Decimal digit to print in range '0'...'9'       ;
;       Effect:         Prints out the digit                            ;
;       Return:         Nothing                                         ;
;-----------------------------------------------------------------------;
WRITE_DIGIT     PROC
        PUSH    AX              ; Save AX and BX
        PUSH    BX
        MOV     AL,DL           ; Make DL an address into a table
        MOV     BX,OFFSET NUMBERS       ; Set DS:BX up for the XLAT
        XLATB                   ; Load character into AL
        MOV     DL,AL           ; Restore DL
        MOV     AH,2h           ; Print character function
        INT     21h
        POP     BX              ; Restore BX and AX
        POP     AX
        RET
WRITE_DIGIT     ENDP

;-----------------------------------------------------------------------;
;               WRITE_STR                                               ;
;       Entry:  DL      Number to print out in the string               ;
;       Effect:         Prints out the function header and number       ;
;       Return:         Nothing                                         ;
;-----------------------------------------------------------------------;
WRITE_STR       PROC
        PUSH    AX
        PUSH    DX
        MOV     AH,9h   ; Print string function
        MOV     DX,OFFSET BASE_STR      ; Print out the Function # part
        INT     21h
        POP     DX
        CALL    WRITE_DIGIT     ; Write the digit
        PUSH    DX
        MOV     DX,OFFSET END_STR       ; Print out CR,LF sequence
        INT     21h
        POP     DX
        POP     AX
        RET
WRITE_STR       ENDP

;-----------------------------------------------------------------------;
;       Group of functions                                              ;
FUNCTION0       PROC
        MOV     AH,04Ch         ; Exit program gracefully
        INT     21h
FUNCTION0       ENDP
FUNCTION1       PROC
        MOV     DL,1
        RET
FUNCTION1       ENDP
FUNCTION2       PROC
        MOV     DL,2
        RET
FUNCTION2       ENDP
FUNCTION3       PROC
        MOV     DL,3
        RET
FUNCTION3       ENDP
FUNCTION4       PROC
        MOV     DL,4
        RET
FUNCTION4       ENDP
FUNCTION5       PROC
        MOV     DL,5
        RET
FUNCTION5       ENDP

;-----------------------------------------------------------------------;
;       The main part of the program                                    ;
START_HERE:
        MOV     AX,@DATA        ; Have to do this first
        MOV     DS,AX
LOOP_BEGIN:
        MOV     AH,9h           ; Print string function
        MOV     DX,OFFSET GREETINGS
        INT     21h
        MOV     AH,7h           ; Get character
        INT     21h
        SUB     AL,'0'          ; Convert AL into decimal value
        MOV     BX,OFFSET JUMP_TABLE    ; Prepare for XLATB
        XLATB                   ; Get table value
        XOR     AH,AH           ; Clear out all of AH
        CALL    AX              ; Call the function
        CALL    WRITE_STR       ; Display message
        JMP     LOOP_BEGIN
        END     START_HERE
;       The end of the program                                          ;
;-----------------------------------------------------------------------;

xlat3.asm

;-----------------------------------------------------------------------;
;       XLAT and XLATB                                                  ;
;               What are they?                                          ;
;       Part III                                                        ;
;-----------------------------------------------------------------------;
        .MODEL  TINY
        .CODE
        JMP     START_HERE              ; Jump to beginning of program
MY_DATA:                                ; Give label for a data area
GREETINGS       DB      'Enter a number from 1 to 5, 0 quits',13,10,'$'
BASE_STR        DB      'Function # ','$'
END_STR         DB      13,10,'$'
NUMBERS         DB      '0123456789'
JUMP_TABLE      DB      OFFSET FUNCTION0        ; The table of jumps
                DB      OFFSET FUNCTION1
                DB      OFFSET FUNCTION2
                DB      OFFSET FUNCTION3
                DB      OFFSET FUNCTION4
                DB      OFFSET FUNCTION5
MY_STACK        DW      32 DUP(?)       ; Make space for a stack
;-----------------------------------------------------------------------;
;               WRITE_DIGIT                                             ;
;       Entry:  DL      Decimal digit to print in range '0'...'9'       ;
;       Effect:         Prints out the digit                            ;
;       Return:         Nothing                                         ;
;-----------------------------------------------------------------------;
WRITE_DIGIT     PROC
        PUSH    AX              ; Save AX and BX
        PUSH    BX
        MOV     AL,DL           ; Make DL an address into a table
        MOV     BX,OFFSET NUMBERS       ; Set DS:BX up for the XLAT
        XLATB                   ; Load character into AL
        MOV     DL,AL           ; Restore DL
        MOV     AH,2h           ; Print character function
        INT     21h
        POP     BX              ; Restore BX and AX
        POP     AX
        RET
WRITE_DIGIT     ENDP

;-----------------------------------------------------------------------;
;               WRITE_STR                                               ;
;       Entry:  DL      Number to print out in the string               ;
;       Effect:         Prints out the function header and number       ;
;       Return:         Nothing                                         ;
;-----------------------------------------------------------------------;
WRITE_STR       PROC
        PUSH    AX
        PUSH    DX
        MOV     AH,9h   ; Print string function
        MOV     DX,OFFSET BASE_STR      ; Print out the Function # part
        INT     21h
        POP     DX
        CALL    WRITE_DIGIT     ; Write the digit
        PUSH    DX
        MOV     DX,OFFSET END_STR       ; Print out CR,LF sequence
        INT     21h
        POP     DX
        POP     AX
        RET
WRITE_STR       ENDP

;-----------------------------------------------------------------------;
;       Group of functions                                              ;
FUNCTION0       PROC
        MOV     AH,04Ch         ; Exit program gracefully
        INT     21h
FUNCTION0       ENDP
FUNCTION1       PROC
        MOV     DL,1
        RET
FUNCTION1       ENDP
FUNCTION2       PROC
        MOV     DL,2
        RET
FUNCTION2       ENDP
FUNCTION3       PROC
        MOV     DL,3
        RET
FUNCTION3       ENDP
FUNCTION4       PROC
        MOV     DL,4
        RET
FUNCTION4       ENDP
FUNCTION5       PROC
        MOV     DL,5
        RET
FUNCTION5       ENDP

;-----------------------------------------------------------------------;
;       The main part of the program                                    ;
START_HERE:
        MOV     AX,@CODE        ; Have to do this first
        MOV     DS,AX
        MOV     AX,OFFSET MY_STACK
        MOV     SS,AX
LOOP_BEGIN:
        MOV     AH,9h           ; Print string function
        MOV     DX,OFFSET GREETINGS
        INT     21h
        MOV     AH,7h           ; Get character
        INT     21h
        SUB     AL,'0'          ; Convert AL into decimal value
        MOV     BX,OFFSET JUMP_TABLE    ; Prepare for XLATB
        XLATB                   ; Get table value
        XOR     AH,AH           ; Clear out all of AH
        CALL    AX              ; Call the function
        CALL    WRITE_STR       ; Display message
        JMP     LOOP_BEGIN
        END     START_HERE
;       The end of the program                                          ;
;-----------------------------------------------------------------------;

Set of assembler programs found on old 5.25 floppy disks from when I was a huge nerd at Thomas Jefferson High School for Science and Technology in the computer systems lab between 1988 and 1992.

It appears to be work for my "Computer Architecture" class.

Anyone can do whatever they'd like to with them--if anything.

And, yes, I remain a crushingly huge nerd.