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#108102 - 12/01/16 10:11 PM Re: HP Integral PC (1985) WIP [Re: shattered]  
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Just Desserts Offline
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So it gives you a larger desktop area if, ironically enough, it sets _desktop to 0? That's... interesting, to say the least. smile

#108103 - 12/01/16 10:43 PM Re: HP Integral PC (1985) WIP [Re: shattered]  
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Likely a 'prototype' mode -- HPJ article mentions that GPU can also drive a CRT, at up to 1024x1024 px.

#108105 - 12/02/16 02:10 PM Re: HP Integral PC (1985) WIP [Re: shattered]  
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R. Belmont Offline
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Maybe the underscore meant "inverted logic" smile

#108118 - 12/05/16 12:09 AM Re: HP Integral PC (1985) WIP [Re: shattered]  
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My next target is bitblt feature of the GPU. If there's existing code that operates on 16-bit words, I'd reuse it; MAME doesn't seem to have that.

AT&T DMD 5620 source has bitblt.c but it uses WE32K assembler heavily -- https://github.com/shattered/dmd-5620rom/blob/master/5620rom/src/lib/libj/bitblt.c

X11's ddx/mfb should have something but I got lost in the maze of different functions, all alike.

(or I could try and write it from scratch, using http://research.swtch.com/bitblt and http://bitsavers.trailing-edge.com/pdf/xerox/alto/BitBLT_Nov1975.pdf as references...)

#108119 - 12/05/16 12:43 AM Re: HP Integral PC (1985) WIP [Re: shattered]  
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Al Kossow Offline
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Originally Posted By shattered
My next target is bitblt feature of the GPU. If there's existing code that operates on 16-bit words, I'd reuse it; MAME doesn't seem to have that.

AT&T DMD 5620 source has bitblt.c but it uses WE32K assembler heavily -- https://github.com/shattered/dmd-5620rom/blob/master/5620rom/src/lib/libj/bitblt.c

X11's ddx/mfb should have something but I got lost in the maze of different functions, all alike.

(or I could try and write it from scratch, using http://research.swtch.com/bitblt and http://bitsavers.trailing-edge.com/pdf/xerox/alto/BitBLT_Nov1975.pdf as references...)


how portable does the bitblt instruction in the Alto look?

#108130 - 12/05/16 06:39 PM Re: HP Integral PC (1985) WIP [Re: shattered]  
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#108131 - 12/05/16 07:04 PM Re: HP Integral PC (1985) WIP [Re: shattered]  
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Just Desserts Offline
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holy fuck

#108133 - 12/05/16 07:26 PM Re: HP Integral PC (1985) WIP [Re: Just Desserts]  
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Al Kossow Offline
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Originally Posted By Just Desserts


holy fuck


sorry, I forgot we actually execute the Alto microcode. earlier emulators simulated the bitblt instruction.

i'm sure there has to be a portable 1bpp blt example somewhere
but it's probably easier just to do one from scratch

#108134 - 12/05/16 07:28 PM Re: HP Integral PC (1985) WIP [Re: shattered]  
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R. Belmont Offline
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Yeah, you probably could've written one in the time it's taken for people to hunt smile

#108135 - 12/05/16 08:21 PM Re: HP Integral PC (1985) WIP [Re: shattered]  
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I hate doing bit arithmetic, it's unnatural for my organic brain smile

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