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Binary-coded decimal arithmetic?
#288605 - 06/03/12 06:35 PM
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I have been looking for good algorithms for binary-coded decimal arithmetic. The best I have been able to find is this page and it really doesn't go into as much detail as I would like. In particular, it says nothing about multiplication or division. Also, I suspect the addition and subtraction algorithms could be improved upon.
I want to know what algorithms for BCD arithmetic anyone might have come across in games. For example, I have seen Web pages giving very detailed information about the workings of Pac-Man, but of course they wouldn't have the "boring" stuff such as how the points are actually added up. Also, I am curious as to how games that multiply numbers (for example, Giga Wing, and some gambling games) do so.
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Quantum Leaper |
OCRer and Monkey Typist for Galaxy Game
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Reged: 03/08/04
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Posts: 198
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Loc: Orion spiral arm of the Milky Way
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Re: Binary-coded decimal arithmetic?
[Re: amused]
#288987 - 06/09/12 03:53 AM
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> I have been looking for good algorithms for binary-coded decimal arithmetic. The best > I have been able to find is > this page and it really doesn't go into as much detail as I would like. In > particular, it says nothing about multiplication or division. Also, I suspect the > addition and subtraction algorithms could be improved upon. > I used to convert to Binary first, the do the BCD arithmetic on my C64, since the multiplication and division used to take far longer than conversion.
> I want to know what algorithms for BCD arithmetic anyone might have come across in > games. For example, I have seen Web pages giving very detailed information about the > workings of Pac-Man, but of course they wouldn't have the "boring" stuff such as how > the points are actually added up. Also, I am curious as to how games that multiply > numbers (for example, Giga Wing, and some gambling games) do so.
I know Bard's Tale 2 or 3 on the C64 uses BCD for amount of gold your characters have. I wrote a cheat program for Bard's Tale 1,2 and 3 on the C64, I even have the source code for BT2 and BT3 cheat programs in D64 format. My cheat program never really did any kind of arithmetic, since all I had to do was show the number and edit them.
Edited by Quantum Leaper (06/09/12 03:58 AM)
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Re: Binary-coded decimal arithmetic?
[Re: amused]
#289226 - 06/12/12 12:54 AM
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> I have been looking for good algorithms for binary-coded decimal arithmetic. The best > I have been able to find is
You could look in the roms for the Microbee or the Super-80. These computers store their floating-point numbers as BCD.
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