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TMS9900 CPU core creation attempt

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#126 Sinphaltimus OFFLINE  


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Posted Thu Feb 1, 2018 12:52 PM

We are all very excited about all of your projects. I for one would love to be able to reproduce your FPGA TI-99/4a as a stand-alone unit. I have an empty console case and keyboard just waiting for it. :) And am following ET-PEB with bated breath....

#127 speccery OFFLINE  



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Posted Sat May 19, 2018 12:27 PM

I'll also note in this thread that if you're interested in FPGA based TMS9900 stuff, there is an update in pnr's TMS9902 VHDL thread. I've setup a repository with a little explanation at: https://github.com/Speccery/breadboard

#128 speccery OFFLINE  



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Posted Sat Sep 22, 2018 2:26 PM

Wow its been a long time without updates! The TI Treff is on-going in Germany, I did not have the time to go there, but inspired by the event - and also by the fact that after my house move my work room is beginning to be in good shape - I booted both version of my FPGA TI-99/4A. I was happy to see that both FPGA boards still work. The other one had the TMS99105 daughterboard plugged in, while the other was running my VHDL TMS9900 core. I spent some time working on the latter, fixing a couple of reset related problems - and discovering a bug. Apparently even from BASIC my CPU claims the 1*-1 equals 1. Well whatever, the negative numbers are just a nuisance :)



#129 speccery OFFLINE  



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Posted Yesterday, 1:47 PM

Yesterday and today I fixed in total four bugs in the FPGA CPU, these are documented in two blog postings, here is a link to the latter one. Three bugs with flag handling and one major bug in the hardware divider fixed.



#130 TheMole OFFLINE  



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Posted Yesterday, 3:23 PM

Always love reading about your progress.

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