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Atari demoscene BBS
| 32 bit muls |
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Posted by: PeyloW
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May,15.2014-22:51
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Is there a nice lib out there for fast 32bit muls on plain 68000?
I have a 32b*16b->32b down to 120/200 cycles (best/worst case).
And 32b*32b->32b to 164/284 cycles (Can save another 8 cycles if I allow d3 to be clobbered).
But from here to a 32b*32b->64b result my code kind of fails at 300/472 cycles. Which is dumb since it is the same number of mulu.w instructions, but I store the 64 bit result in memory, which is costly.
I feel dumb but I can not figure out how to do that one in regs only :/.
In all honesty only the middle 32bits are of interest to me, since what I want is really a 16.16*16.16 fix point multiply.
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[All messages in this thread] [Start new thread]
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Topic
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Posted by
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Date
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32 bit muls
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PeyloW
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May,15.2014-22:51
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Re: 32 bit muls
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ggn
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May,17.2014-07:58
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Re: 32 bit muls
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ggn
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May,17.2014-08:00
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Re: 32 bit muls
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PeyloW
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May,17.2014-15:05
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Re: 32 bit muls
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PeyloW
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May,18.2014-17:55
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Re: 32 bit muls
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bob_er/mec
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May,17.2014-09:57
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Re: 32 bit muls
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Alien / ST-CNX
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May,21.2014-21:14
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Re: 32 bit muls
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PeyloW
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May,22.2014-10:52
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Re: 32 bit muls
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PeyloW
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May,23.2014-10:10
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Re: 32 bit muls
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dml
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May,23.2014-22:29
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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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