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Atari coding BBS
| DSP frac arithmetic help |
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Posted by: Laurent / Thadoss
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Feb,27.2015-15:03
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Hi,
Until now, I've always coded the DSP with integer arithmetic.
I'm trying to play with a fractional representation of numbers :
0 = 0 ;)
-1 = $800000
1 = $7fffff
0.5 = $3fffff
-0.5 = $400000
So I read the value -1 from x memory and I want to get its absolute value :
move x:value,x0 -----> x0=$800000
move x0,a -----------> A = $ff 800000 000000
abs a ---------------> A = $00 800000 000000
I would have expected A to be like $00 7fffff ffffff
What is wrong ?
How should I get the ABS value of -1 ?
Regads
Laurent
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Topic
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Posted by
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Date
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DSP frac arithmetic help
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Laurent / Thadoss
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Feb,27.2015-15:03
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Re: DSP frac arithmetic help
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Laurent / Thadoss
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Feb,27.2015-15:08
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Re: DSP frac arithmetic help
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dml
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Feb,27.2015-15:28
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Re: DSP frac arithmetic help
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Laurent / Thadoss
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Feb,27.2015-18:32
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Re: DSP frac arithmetic help
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dml
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Feb,27.2015-18:42
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Re: DSP frac arithmetic help
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dml
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Feb,27.2015-18:46
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Re: DSP frac arithmetic help
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Splash/S1
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Feb,27.2015-20:21
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Re: DSP frac arithmetic help
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dml
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Feb,27.2015-20:38
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Re: DSP frac arithmetic help
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Laurent / Thadoss
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Feb,27.2015-20:42
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Re: DSP frac arithmetic help
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mikro
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Feb,28.2015-10:44
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Re: DSP frac arithmetic help
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dml
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Feb,28.2015-12:35
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What's the anti-troll code?
That's your personal code to be able to add comments and messages on the dhs.nu site.
Don't have a code or forgot it? Fix it here.
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