Divide Overflow Error Asm
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Divide By Zero Or Overflow Error
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Divide Error Overflow Emu8086
up Divide overflow in Assembly language up vote 0 down vote favorite I have a simple assembly program, where I want to divide two numbers (two byte sized) and print remainder. Here's my code .model small .stack 256 .data ten dw 10
Your Program Caused A Divide Overflow Error
.code main proc mov ax, @data mov ds, ax mov ax, 12 ; divident div ten ; ax/10 mov ah, 9 ; for printing dx int 21h mov ax, 4c00h ; ending program int 21h main endp end main So when I run this code the result is "Divide overflow" and I have no idea why does overflow happens. Any ideas? assembly x86 division share|improve this question edited Apr 6 '13 at 11:52 nrz 7,71721453 asked Apr 6 '13 at 11:34 nabroyan 1,2121526 1 divide overflow is generated when Have you tried searching for assembly division problems/questions? Your question is not the first one. It's a duplicate of others. –Alexey Frunze Apr 6 '13 at 11:50 add a comment| 3 Answers 3 active oldest votes up vote 1 down vote accepted DIV mem16 divides DX:AX by the given operand. So you need to sign-extend AX into DX, which you easily can do with the CWD instruction prior to the division (in your case MOV DX,0 or XOR DX,DX would also work). I.e.: mov ax,12 cwd div ten Another problem with your code is that you seem to assume that int 21h / ah=9 can be used to print numeric values. That is not the case. If you want to print the value of DX (i.e. the remainder) you'll have to convert it into a string first and print that string. Otherwise you'll just get garbage output, and your program might even crash. share|improve this answer edited Apr 6 '13 at 11:46 answered Apr 6 '13 at 11:40 Michael 33.7k82863 The interesting thing is that when I debug my code everything is correct, but when it tries to print value, it prints garbage in debug mode and "Divide overflow" in normal mode –nabroyan Apr 6 '13 at 12:01 Debugger clears DX for you. –Harold Apr 6 '13 at 12:06 In some environments you might end up with DX being 0 when your program starts. In those instances the division would work corr
when you try to preform division by zero. This is an illegal operation and causes an exception. Posted on 2006-04-17 09:36:25 by Synfire Re: divide overflow From division overflow error "Art of Assembly"Division by zero and Division Overflow (they're NOT the same thing):You spinrite division overflow error cannot, on the 80x86, simply divide one eight bit value by another. If the denominator is an eight bit division overflow error b022 value, the numerator must be a sixteen bit value. If you need to divide one unsigned eight bit value by another, you must zero extend the numerator to sixteen bits. You can http://stackoverflow.com/questions/15850409/divide-overflow-in-assembly-language accomplish this by loading the numerator into the al register and then moving zero into the ah register. Then you can divide ax by the denominator operand to produce the correct result. Failing to zero extend al before executing div may cause the 80x86 to produce incorrect results! When you need to divide two 16 bit unsigned values, you must zero extend the ax register http://www.asmcommunity.net/forums/topic/?id=24616 (which contains the numerator) into the dx register. Just load the immediate value zero into the dx register12. If you need to divide one 32 bit value by another, you must zero extend the eax register into edx (by loading a zero into edx) before the division. When dealing with signed integer values, you will need to sign extend al to ax, ax to dx or eax into edx before executing idiv. To do so, use the cbw, cwd, cdq, or movsx instructions. If the H.O. byte or word does not already contain significant bits, then you must sign extend the value in the accumulator (al/ax/eax) before doing the idiv operation. Failure to do so may produce incorrect results. There is one other catch to the 80x86’s divide instructions: you can get a fatal error when using this instruction. First, of course, you can attempt to divide a value by zero. Furthermore, the quotient may be too large to fit into the eax, ax, or al register. For example, the 16/8 division “8000h / 2??? produces the quotient 4000h with a remainder of zero. 4000h will not fit into eight
Join INTELLIGENT WORK FORUMSFOR COMPUTER PROFESSIONALS Log In Come Join Us! Are you aComputer / IT professional?Join Tek-Tips Forums! Talk With Other Members Be Notified Of ResponsesTo Your Posts Keyword Search One-Click Access To http://www.tek-tips.com/viewthread.cfm?qid=1123341 YourFavorite Forums Automated SignaturesOn Your Posts Best Of All, It's Free! Join Us! *Tek-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail. Posting Guidelines Promoting, selling, recruiting, http://www.programmersheaven.com/discussion/94598/divide-overflow-error coursework and thesis posting is forbidden.Tek-Tips Posting Policies Jobs Jobs from Indeed What: Where: jobs by Link To This Forum! Add Stickiness To Your Site By Linking To This Professionally Managed Technical Forum.Just copy overflow error and paste the BBCode HTML Markdown MediaWiki reStructuredText code below into your site. Assembly Forum at Tek-Tips HomeForumsProgrammersLanguagesAssembly Forum predicting a divide overflow. 2 thread272-1123341 Forum Search FAQs Links MVPs predicting a divide overflow. predicting a divide overflow. denc4 (Programmer) (OP) 15 Sep 05 18:09 let's say you got this code:; 20002h \ 2.mov ax,2mov dx,axmov bx,axdiv bxresult would be 10001h, which ofcourse does not fit in divide overflow error ax:a divide overflow error is generated.Is it possible to predict a divide overflow before itoccurs? RE: predicting a divide overflow. 2 TessaBonting (TechnicalUser) 22 Sep 05 03:48 Yes, do a compare on dx with bx and if ae then its anoverflow.movax,2movdx,axmovbx,2cmpdx,bxjaeerrordivbxok:error:succes, Tessa RE: predicting a divide overflow. denc4 (Programmer) (OP) 22 Sep 05 12:16 That makes sense.I'm not a math person myself, so I am strugling with thelogic behind it. But I have executed some experimental codebased on your example and it seems to work fine.thank you. RE: predicting a divide overflow. TessaBonting (TechnicalUser) 23 Sep 05 11:34 Look it like this:100.000/10 gives 10.000 if you now look at the three zeros afther the dot then that is the ax registerand the 100 is the dx register.by dividing you see that afther the division ax can't hold the whole 10.000.so when you divide the 100.000 by 200 it gives .500 and that can be holded in ax.try it with dividing by 100 and the result will be 1.000with is just 1 to much to hold since the maximum in thisexxample is 999I hope this explaince the arithmetic behind it a bit.succes, Tessa RE: predicting a divide overflow. denc4 (Programmer) (OP) 25 Se
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