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MacNilly · Feb 14th, 2006, 4:11 AM

Hello all,

I am having a problem with my program that does Ulong's Conjecture. If you don't know what that is, it's pretty simple and the code explains what I'm doing. I got it to display the right numbers, but when I get to the end I am supposed to tell how many numbers were in the series. I ran through it with CodeView and I'm still lost because I can't get codeview to watch variables (they always stay at 0). Basically I'm just getting a junk value always around ~400. Please help me understand why my program is not counting right. And also if anyone knows why CodeView won't let me watch variables.

(Toggle Plain Text)

;=============================================================================
;       Ulong's Conjecture Program
;       Starting with any number,
;	 if the number is even divide it by 2
;	 if the number is odd multiply it by 3 and add 1
;	Stop when you get to number 1
;=============================================================================
                EXTRN   GETDEC$:FAR
                EXTRN   NEWLINE:FAR
                EXTRN   PUTDEC$:FAR
                EXTRN   PUTSTRNG:FAR
;=============================================================================
                DOSSEG
                .MODEL  SMALL
;=============================================================================
                .STACK  256
;=============================================================================
                .DATA
NUM             DW      ?
CNT             DW      0
PROMPT          DB      'Enter a positive integer: '
OUTPUT          DB      'Numbers in this series: '
;=============================================================================
                .CODE
ULONGS          PROC
                MOV     AX, SEG DGROUP
                MOV     ES, AX
                LEA     DI, PROMPT
                MOV     CX, 26
                CALL    PUTSTRNG
                CALL    GETDEC$
                MOV     NUM, AX

DO_NEXT:        MOV     AX, NUM
                INC     CNT
                MOV     BH, 0
                CALL    PUTDEC$
                CALL    NEWLINE
                CMP     AX, 1
                JE      DONE
                SUB     DX, DX
                MOV     BX, 2
                DIV     BX
                CMP     DX, 0
                JNE     IS_ODD

IS_EVEN:        MOV     NUM, AX
                JMP     DO_NEXT

IS_ODD:         MOV     AX, NUM
                MOV     BX, 3
                MUL     BX
                MOV     NUM, AX
                INC     NUM
                JMP     DO_NEXT
DONE:
                LEA     DI, OUTPUT
                MOV     CX, 24
                CALL    PUTSTRNG
                MOV     AX, CNT
                CALL    PUTDEC$
                .EXIT
ULONGS          ENDP
                END     ULONGS

;=============================================================================
;       Ulong's Conjecture Program
;       Starting with any number,
;	 if the number is even divide it by 2
;	 if the number is odd multiply it by 3 and add 1
;	Stop when you get to number 1
;=============================================================================
                EXTRN   GETDEC$:FAR
                EXTRN   NEWLINE:FAR
                EXTRN   PUTDEC$:FAR
                EXTRN   PUTSTRNG:FAR
;=============================================================================
                DOSSEG
                .MODEL  SMALL
;=============================================================================
                .STACK  256
;=============================================================================
                .DATA
NUM             DW      ?
CNT             DW      0
PROMPT          DB      'Enter a positive integer: '
OUTPUT          DB      'Numbers in this series: '
;=============================================================================
                .CODE
ULONGS          PROC
                MOV     AX, SEG DGROUP
                MOV     ES, AX
                LEA     DI, PROMPT
                MOV     CX, 26
                CALL    PUTSTRNG
                CALL    GETDEC$
                MOV     NUM, AX

DO_NEXT:        MOV     AX, NUM
                INC     CNT
                MOV     BH, 0
                CALL    PUTDEC$
                CALL    NEWLINE
                CMP     AX, 1
                JE      DONE
                SUB     DX, DX
                MOV     BX, 2
                DIV     BX
                CMP     DX, 0
                JNE     IS_ODD

IS_EVEN:        MOV     NUM, AX
                JMP     DO_NEXT

IS_ODD:         MOV     AX, NUM
                MOV     BX, 3
                MUL     BX
                MOV     NUM, AX
                INC     NUM
                JMP     DO_NEXT
DONE:
                LEA     DI, OUTPUT
                MOV     CX, 24
                CALL    PUTSTRNG
                MOV     AX, CNT
                CALL    PUTDEC$
                .EXIT
ULONGS          ENDP
                END     ULONGS

DaWei · Feb 14th, 2006, 8:04 AM

It's been a long time since I've used this; should you be setting BH to zero before calling that last PUTDEC$? I have no ideas regarding CodeView.

MacNilly · Feb 15th, 2006, 1:16 AM

Tried that but same result. Also I tried changing the first 2 lines of the .CODE segment to

(Toggle Plain Text)

MOV AX, @DATA
MOV ES, AX

Because I didn't know what in the world "SEG DGROUP" was. Also I removed the line "DOSSEG" from just above the .STACK definition and the output was "Numbers in this series: ~1024." Also the only command that alters CNT is "INC CNT" so that's not the problem. Also, any number greater than 500 crashes the program with a Windows 16 Bit DOS Subsystem fault.
/sigh

The Dark · Feb 15th, 2006, 3:38 AM

I just tried this in inline (C++) assembly (minus the input and output routines) and it seemed to work OK. Note that this was in a 32 bit compiler, so it may not show anything.
Are you sure PUTDEC$ and NEWLINE don't do anything nasty like change the value of AX? That would muck up your program pretty well.

MacNilly · Feb 15th, 2006, 5:56 AM

Yeah mostly got it working now. It works for all the test numbers my instructor gave us except for one number where it just infinite loops and outputs 0's.

Feb 14th, 2006, 4:11 AM	#1
MacNilly Newbie Join Date: Feb 2006 Location: Sacramento, CA Posts: 4 Rep Power: 0	Problem with Ulong's Conjecture Program Hello all, I am having a problem with my program that does Ulong's Conjecture. If you don't know what that is, it's pretty simple and the code explains what I'm doing. I got it to display the right numbers, but when I get to the end I am supposed to tell how many numbers were in the series. I ran through it with CodeView and I'm still lost because I can't get codeview to watch variables (they always stay at 0). Basically I'm just getting a junk value always around ~400. Please help me understand why my program is not counting right. And also if anyone knows why CodeView won't let me watch variables. (Toggle Plain Text) ;============================================================================= ; Ulong's Conjecture Program ; Starting with any number, ; if the number is even divide it by 2 ; if the number is odd multiply it by 3 and add 1 ; Stop when you get to number 1 ;============================================================================= EXTRN GETDEC$:FAR EXTRN NEWLINE:FAR EXTRN PUTDEC$:FAR EXTRN PUTSTRNG:FAR ;============================================================================= DOSSEG .MODEL SMALL ;============================================================================= .STACK 256 ;============================================================================= .DATA NUM DW ? CNT DW 0 PROMPT DB 'Enter a positive integer: ' OUTPUT DB 'Numbers in this series: ' ;============================================================================= .CODE ULONGS PROC MOV AX, SEG DGROUP MOV ES, AX LEA DI, PROMPT MOV CX, 26 CALL PUTSTRNG CALL GETDEC$ MOV NUM, AX DO_NEXT: MOV AX, NUM INC CNT MOV BH, 0 CALL PUTDEC$ CALL NEWLINE CMP AX, 1 JE DONE SUB DX, DX MOV BX, 2 DIV BX CMP DX, 0 JNE IS_ODD IS_EVEN: MOV NUM, AX JMP DO_NEXT IS_ODD: MOV AX, NUM MOV BX, 3 MUL BX MOV NUM, AX INC NUM JMP DO_NEXT DONE: LEA DI, OUTPUT MOV CX, 24 CALL PUTSTRNG MOV AX, CNT CALL PUTDEC$ .EXIT ULONGS ENDP END ULONGS ;============================================================================= ; Ulong's Conjecture Program ; Starting with any number, ; if the number is even divide it by 2 ; if the number is odd multiply it by 3 and add 1 ; Stop when you get to number 1 ;============================================================================= EXTRN GETDEC$:FAR EXTRN NEWLINE:FAR EXTRN PUTDEC$:FAR EXTRN PUTSTRNG:FAR ;============================================================================= DOSSEG .MODEL SMALL ;============================================================================= .STACK 256 ;============================================================================= .DATA NUM DW ? CNT DW 0 PROMPT DB 'Enter a positive integer: ' OUTPUT DB 'Numbers in this series: ' ;============================================================================= .CODE ULONGS PROC MOV AX, SEG DGROUP MOV ES, AX LEA DI, PROMPT MOV CX, 26 CALL PUTSTRNG CALL GETDEC$ MOV NUM, AX DO_NEXT: MOV AX, NUM INC CNT MOV BH, 0 CALL PUTDEC$ CALL NEWLINE CMP AX, 1 JE DONE SUB DX, DX MOV BX, 2 DIV BX CMP DX, 0 JNE IS_ODD IS_EVEN: MOV NUM, AX JMP DO_NEXT IS_ODD: MOV AX, NUM MOV BX, 3 MUL BX MOV NUM, AX INC NUM JMP DO_NEXT DONE: LEA DI, OUTPUT MOV CX, 24 CALL PUTSTRNG MOV AX, CNT CALL PUTDEC$ .EXIT ULONGS ENDP END ULONGS

Feb 14th, 2006, 8:04 AM	#2
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	It's been a long time since I've used this; should you be setting BH to zero before calling that last PUTDEC$? I have no ideas regarding CodeView. __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

Feb 15th, 2006, 1:16 AM	#3
MacNilly Newbie Join Date: Feb 2006 Location: Sacramento, CA Posts: 4 Rep Power: 0	Tried that but same result. Also I tried changing the first 2 lines of the .CODE segment to (Toggle Plain Text) MOV AX, @DATA MOV ES, AX MOV AX, @DATA MOV ES, AX Because I didn't know what in the world "SEG DGROUP" was. Also I removed the line "DOSSEG" from just above the .STACK definition and the output was "Numbers in this series: ~1024." Also the only command that alters CNT is "INC CNT" so that's not the problem. Also, any number greater than 500 crashes the program with a Windows 16 Bit DOS Subsystem fault. /sigh

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Feb 15th, 2006, 3:38 AM	#4
The Dark Expert Programmer Join Date: Jun 2005 Posts: 810 Rep Power: 4	I just tried this in inline (C++) assembly (minus the input and output routines) and it seemed to work OK. Note that this was in a 32 bit compiler, so it may not show anything. Are you sure PUTDEC$ and NEWLINE don't do anything nasty like change the value of AX? That would muck up your program pretty well.

Feb 15th, 2006, 5:56 AM	#5
MacNilly Newbie Join Date: Feb 2006 Location: Sacramento, CA Posts: 4 Rep Power: 0	Yeah mostly got it working now. It works for all the test numbers my instructor gave us except for one number where it just infinite loops and outputs 0's.

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Programming Forums > Application Development > Assembly

Problem with Ulong's Conjecture Program