.MODEL SMALL,BASIC,FARSTACK
;==============================================================================
;
    EXTRN CLEAR:FAR                ;CLEAR SCREEN
        EXTRN GETDEC:FAR               ;PROCEDURE TO 16-BIT INTEGER
    EXTRN GETDEC$:FAR    ;DISPLAY 32-BIT INTEGER
        EXTRN NEWLINE:FAR              ;DISPLAY NEWLINE
    EXTRN PUTDEC:FAR      ;DISPLAY 16-BIT INTEGER
        EXTRN PUTDEC$:FAR              ;DISPLAY 16-BIT INTEGER
    EXTRN PUTDC32$:FAR
        EXTRN PUTSTRNG:FAR            ;DISPLAY CHARACTER STRING
        EXTRN PAUSE:FAR              ;PAUSE SCREEN
;==============================================================================
;
; STACK SEGMENT DEFINITION
;
    .STACK 256
;==============================================================================
;
; CONSTANT SEGMENT DEFINITION
;
        .DATA
NUM             DW        ?
CONSTANTDIV    DB        2
COUNTER        DW        0
PROMPT        DB        13,10,'PLEASE ENTER A POSITIVE NUMBER: '
LENGTHS        DB        'LENGTH OF SEQUENCE IS: '
ERROR        DB        'FLOATING POINT ERROR'
SPACE        DB        ' '
;==============================================================================
;
; CODE SEGMENT DEFINITION
;
    .CODE
    ASSUME DS:NOTHING,ES:DGROUP
ULAMSEQ:    
MAIN PROC    ;BEGINNING OF PROCEDURE
          MOV    AX,DGROUP    
    MOV    ES,AX        
    MOV    DS,AX        
    CALL    CLEAR        
    LEA    DI,PROMPT    
    MOV    CX,34        
    CALL     PUTSTRNG    
    CALL    GETDEC$    
    CALL    NEWLINE    
START_LOOP:        ;LOOP BEGIN
    SUB    DX,DX
    MOV    BH,0
    CALL    PUTDEC$        
    MOV    NUM,AX    ;MAKE SURE VALUE IN AX IS NOT ALTERED
    LEA    DI,SPACE;FORMAT THE NUMBER LINE
    MOV    CX,1
    CALL    PUTSTRNG
    INC    COUNTER        
    CMP    AX,1    ;MAKE SURE DECIMAL IS GREATER THAN 1
    JLE    END_LOOP;VALUE IS EQUAL OR LESS JUMPS OUT OF LOOP        
;MOV    BX,2        
    DIV      CONSTANTDIV;MATH COMPUTATION IF EVEN OR ODD
    CMP    DX,0    ;IF EVEN GOES TO START LOOP OVER
    CLI
    JE    START_LOOP            
    JMP    DOODD    ;IF ODD JUMPS TO DO ODD ARITHMETIC
DOODD:            ;BEGIN FOR ODD ARITHMETIC
    MOV    AX,NUM        
    MOV        BX,3        
    MUL    BX    
    INC    AX
    JC    ERROR_MESSAGE;CHECK FOR FLOATING POINT ERROR
    JMP    START_LOOP    ;OTHER JUMPS BACK TO LOOP
ERROR_MESSAGE:                 ;PRINTS OUT ERROR MESSAGE
    CALL    NEWLINE;
    LEA    DI,ERROR;PROCEDURE JUMP OUT OF LOOP AND END PROGRAM
    MOV    CX,20    ;IF A FLOATING POINT OCCURS
    CALL    PUTSTRNG    
    JMP    DONE            
END_LOOP:        ;END LOOP
    MOV    AX,COUNTER;MOV COUNTER TO AX REGISTRY FOR PRINT
    CALL    NEWLINE                
    LEA    DI,LENGTHS;PRINTS LENGTH OF PROGRAM
    MOV    CX,23    
    CALL    PUTSTRNG    
    CALL    PUTDEC
    CALL    NEWLINE
    LEA    DI,SPACE
    MOV    CX,1
    CALL    PAUSE        
DONE:    
    MOV    AX,4C00CH;RETURN TO DOS
    INT    21H            
MAIN    ENDP
    END ULAMSEQ

   SHR AX,1    ; LSB now in carry bit
   JNC  Even         ; Jump no carry if Even
    ; Odd
   JZ    Done        ;  if zero and carry was set then AX was (1)