Brendan G Bohannon
@bgbtech.bsky.social
Hobbyist programmer (C, Verilog, ASM, etc), CPU and ISA design, have my own C compiler, 3D and GL, ..., and sometimes electronics.
ASD/aspie, single (ace/demi), Gen Y. Currently lives in Tulsa, OK.
ASD/aspie, single (ace/demi), Gen Y. Currently lives in Tulsa, OK.
Pinned
Brendan G Bohannon
@bgbtech.bsky.social
· Nov 14
GitHub - cr88192/bgbtech_btsr1arch: BtSR1 and BJX2 ISA / CPU Architecture
BtSR1 and BJX2 ISA / CPU Architecture. Contribute to cr88192/bgbtech_btsr1arch development by creating an account on GitHub.
github.com
New here, testing this out...
I have created a custom ISA, with emulator, Verilog implementation, and C compiler, here:
github.com/cr88192/bgbt...
Runs a custom ISA but now also can run RV64 (in userland), mostly targeting FPGA but aiming for OK performance. Mostly experimenting with ISA design.
I have created a custom ISA, with emulator, Verilog implementation, and C compiler, here:
github.com/cr88192/bgbt...
Runs a custom ISA but now also can run RV64 (in userland), mostly targeting FPGA but aiming for OK performance. Mostly experimenting with ISA design.
If there is one thing that is a merit of BlueSky over X right now, it is that the feed isn't just an endless stream of AI videos... Looking back over on a new X account, very little interesting; any sense of community lost to a stream of random AI generated videos and AI related content... Grr...
September 18, 2026 at 6:51 PM
If there is one thing that is a merit of BlueSky over X right now, it is that the feed isn't just an endless stream of AI videos... Looking back over on a new X account, very little interesting; any sense of community lost to a stream of random AI generated videos and AI related content... Grr...
Goes and watches videos, sees a video complaining about OLED screens and their apparent inability to deliver the viewer's desired levels of HDR contrast in the HDR modes, etc... To me this seems like obvious "first world problems" territory...
September 17, 2026 at 9:49 PM
Goes and watches videos, sees a video complaining about OLED screens and their apparent inability to deliver the viewer's desired levels of HDR contrast in the HDR modes, etc... To me this seems like obvious "first world problems" territory...
Misc: Sees a video talking about BD-R disks. Thinks: Maybe could look into this as an alternative to DVD-R's, notes that BD-R capable internal 5.25" drives are crazy expensive, so no easy drop-in option (external | laptop = more reasonable, but yeah...). I am using a ye olde desktop PC though...
September 16, 2026 at 4:54 PM
Misc: Sees a video talking about BD-R disks. Thinks: Maybe could look into this as an alternative to DVD-R's, notes that BD-R capable internal 5.25" drives are crazy expensive, so no easy drop-in option (external | laptop = more reasonable, but yeah...). I am using a ye olde desktop PC though...
Well, looks like (for better or worse) my former X profile has gone away... So, I guess, now I don't need to care about account recovery anymore, and can now decide whether or not to make another one at some point...
September 15, 2026 at 8:54 AM
Well, looks like (for better or worse) my former X profile has gone away... So, I guess, now I don't need to care about account recovery anymore, and can now decide whether or not to make another one at some point...
Decides to make another go at trying to make RV64GC ELF PIE binaries work on TestKern using a Linux C library (vs my own). Interestingly, now the "ld-linux.so" no longer immediately crashes... It fist tries to make a few 'brk()' syscalls followed by a 'writev()' to fd=2. Seems like sorta progress.
September 12, 2026 at 8:11 PM
Decides to make another go at trying to make RV64GC ELF PIE binaries work on TestKern using a Linux C library (vs my own). Interestingly, now the "ld-linux.so" no longer immediately crashes... It fist tries to make a few 'brk()' syscalls followed by a 'writev()' to fd=2. Seems like sorta progress.
So, I am ending up modifying how my CPU implementation handles RV64GC mode to use untagged link registers in this mode. As I have come to suspect that the use of tagged linked registers may be related to the long standing "ELF PIE binaries using 'ld-linux.so' just violently explode" issue...
September 11, 2026 at 4:32 AM
So, I am ending up modifying how my CPU implementation handles RV64GC mode to use untagged link registers in this mode. As I have come to suspect that the use of tagged linked registers may be related to the long standing "ELF PIE binaries using 'ld-linux.so' just violently explode" issue...
Misc: Started working on a high-level rationale for my XG3 ISA:
github.com/cr88192/bgbt...
I guess, it is mostly a case of "What role could it serve, vs someone just using RV64GC or similar; assuming a CPU with support for both XG3 and RV64GC". But, may still need to work on this a bit more...
github.com/cr88192/bgbt...
I guess, it is mostly a case of "What role could it serve, vs someone just using RV64GC or similar; assuming a CPU with support for both XG3 and RV64GC". But, may still need to work on this a bit more...
bgbtech_btsr1arch/docs/2026-09-28_WhyXG3.adoc at master · cr88192/bgbtech_btsr1arch
BtSR1 and BJX2 ISA / CPU Architecture. Contribute to cr88192/bgbtech_btsr1arch development by creating an account on GitHub.
github.com
September 9, 2026 at 8:21 AM
Misc: Started working on a high-level rationale for my XG3 ISA:
github.com/cr88192/bgbt...
I guess, it is mostly a case of "What role could it serve, vs someone just using RV64GC or similar; assuming a CPU with support for both XG3 and RV64GC". But, may still need to work on this a bit more...
github.com/cr88192/bgbt...
I guess, it is mostly a case of "What role could it serve, vs someone just using RV64GC or similar; assuming a CPU with support for both XG3 and RV64GC". But, may still need to work on this a bit more...
Stepping a little outside of my usual area, but an awkward thought:
Mainline conservatives (particularly the ones in power), for all of their reverence, appear to be doing almost entirely the wrong things if going by Revelation and similar. Not entirely sure what I am supposed to make of this...
Mainline conservatives (particularly the ones in power), for all of their reverence, appear to be doing almost entirely the wrong things if going by Revelation and similar. Not entirely sure what I am supposed to make of this...
September 8, 2026 at 3:04 AM
Stepping a little outside of my usual area, but an awkward thought:
Mainline conservatives (particularly the ones in power), for all of their reverence, appear to be doing almost entirely the wrong things if going by Revelation and similar. Not entirely sure what I am supposed to make of this...
Mainline conservatives (particularly the ones in power), for all of their reverence, appear to be doing almost entirely the wrong things if going by Revelation and similar. Not entirely sure what I am supposed to make of this...
Hmm... Randomly notices that YouTube is a little slow/acting up... Checks the "Stats for Nerds" thing, it is reporting 360 kbps. Tries temporarily enabling a VPN, drops to 164 kbps... Not a huge issue ATM, apart from buffering issues and playback dropping to potato quality (360p and 240p).
September 7, 2026 at 8:01 PM
Hmm... Randomly notices that YouTube is a little slow/acting up... Checks the "Stats for Nerds" thing, it is reporting 360 kbps. Tries temporarily enabling a VPN, drops to 164 kbps... Not a huge issue ATM, apart from buffering issues and playback dropping to potato quality (360p and 240p).
Well, next random thing: Went and got the current form of my BT3 engine working again on my own ISA. Granted, this form is back to a short draw distance to deal with the limitations of a 50MHz CPU and 64MB RAM budget, and needed to reduce the atlas resolution to 256x256, ...
September 7, 2026 at 2:16 AM
Well, next random thing: Went and got the current form of my BT3 engine working again on my own ISA. Granted, this form is back to a short draw distance to deal with the limitations of a 50MHz CPU and 64MB RAM budget, and needed to reduce the atlas resolution to 256x256, ...
And... The DM's / chat on here has gone down... I don't know if random, or if it is some sort of automated block due to too many people messaging me about my former X account or something...
September 5, 2026 at 12:14 AM
And... The DM's / chat on here has gone down... I don't know if random, or if it is some sort of automated block due to too many people messaging me about my former X account or something...
Well, despite what all else is going on right now, I am still working on the random-access image format idea. So, added 8-bit luma and indexed-color variants, and am also working on the 24/32 bit variant (which uses a QOI-like block encoding, but decided to do things differently on a few points).
September 3, 2026 at 5:13 PM
Well, despite what all else is going on right now, I am still working on the random-access image format idea. So, added 8-bit luma and indexed-color variants, and am also working on the 24/32 bit variant (which uses a QOI-like block encoding, but decided to do things differently on a few points).
Well, OK, tried the X support form once again, and this time didn't get an automatic rejection... So, responded to the email, and hopefully this stuff can get sorted out, and hopefully some actual humans look at it... This whole experience has still been annoying.
August 31, 2026 at 5:05 PM
Well, OK, tried the X support form once again, and this time didn't get an automatic rejection... So, responded to the email, and hopefully this stuff can get sorted out, and hopefully some actual humans look at it... This whole experience has still been annoying.
I had done more thinking, and realized my recent random-access compressed image format idea might have uses other than compressed window buffers... So, have expanded it to support a fully serialized format (for files and similar), and have experimented with using it as a crude lossy format, ...
August 31, 2026 at 9:02 AM
I had done more thinking, and realized my recent random-access compressed image format idea might have uses other than compressed window buffers... So, have expanded it to support a fully serialized format (for files and similar), and have experimented with using it as a crude lossy format, ...
Well, anyways, as for CPU/ISA project status:
Not much new, some recent bug fixes mostly.
Gradually working towards some attempts at cleanup:
May gradually phase out XG1 and XG2 modes in favor of XG3;
May drop the original "VUGID" page-protection scheme in favor of solely using page ACLs;
...
Not much new, some recent bug fixes mostly.
Gradually working towards some attempts at cleanup:
May gradually phase out XG1 and XG2 modes in favor of XG3;
May drop the original "VUGID" page-protection scheme in favor of solely using page ACLs;
...
August 30, 2026 at 6:20 PM
Well, anyways, as for CPU/ISA project status:
Not much new, some recent bug fixes mostly.
Gradually working towards some attempts at cleanup:
May gradually phase out XG1 and XG2 modes in favor of XG3;
May drop the original "VUGID" page-protection scheme in favor of solely using page ACLs;
...
Not much new, some recent bug fixes mostly.
Gradually working towards some attempts at cleanup:
May gradually phase out XG1 and XG2 modes in favor of XG3;
May drop the original "VUGID" page-protection scheme in favor of solely using page ACLs;
...
Well, maybe doesn't look like much, but in this case the terrain generation was partly painted in an image editor (BT3 engine). TODO: Explicit control of tree density, ability to paint lakes/water, or maybe ability to run command scripts for automated structure placement or similar...
August 30, 2026 at 6:09 AM
Well, maybe doesn't look like much, but in this case the terrain generation was partly painted in an image editor (BT3 engine). TODO: Explicit control of tree density, ability to paint lakes/water, or maybe ability to run command scripts for automated structure placement or similar...
So, goes and fiddles more with my current 3D engine; and ended up basically doing something the opposite of Minecraft:
Rather than add an option to make the world bigger, added an option to make it smaller. So, world is now variable sized, around 1km to 64km...
Rather than add an option to make the world bigger, added an option to make it smaller. So, world is now variable sized, around 1km to 64km...
August 29, 2026 at 10:15 AM
So, goes and fiddles more with my current 3D engine; and ended up basically doing something the opposite of Minecraft:
Rather than add an option to make the world bigger, added an option to make it smaller. So, world is now variable sized, around 1km to 64km...
Rather than add an option to make the world bigger, added an option to make it smaller. So, world is now variable sized, around 1km to 64km...
Goes and messes with my 3D engine some again: It basically works OK. Notes my usual issue: Almost invariably, once the 3D engine is written and basically working, I almost entirely lose direction and motivation for where to go next. So, three major 3D engines, same core issue each time, alas...
August 27, 2026 at 7:23 AM
Goes and messes with my 3D engine some again: It basically works OK. Notes my usual issue: Almost invariably, once the 3D engine is written and basically working, I almost entirely lose direction and motivation for where to go next. So, three major 3D engines, same core issue each time, alas...
Well, the X access/hacked support form at least seemingly worked this time... So far as it resulted in an automated message to the effect that they aren't going to do crap...
So, I have no idea if my old profile is just sitting idle, or if the hacker still has control over it...
So, I have no idea if my old profile is just sitting idle, or if the hacker still has control over it...
August 25, 2026 at 5:59 AM
Well, the X access/hacked support form at least seemingly worked this time... So far as it resulted in an automated message to the effect that they aren't going to do crap...
So, I have no idea if my old profile is just sitting idle, or if the hacker still has control over it...
So, I have no idea if my old profile is just sitting idle, or if the hacker still has control over it...
So, very random idea:
Implementing a special purpose image compressor designed to allow random access to blocks of pixels (without needing to decompress the whole image), and incremental modification; without the loss of fidelity inherent in color-cell formats. Intended for use in a GUI / WM...
Implementing a special purpose image compressor designed to allow random access to blocks of pixels (without needing to decompress the whole image), and incremental modification; without the loss of fidelity inherent in color-cell formats. Intended for use in a GUI / WM...
August 24, 2026 at 3:09 AM
So, very random idea:
Implementing a special purpose image compressor designed to allow random access to blocks of pixels (without needing to decompress the whole image), and incremental modification; without the loss of fidelity inherent in color-cell formats. Intended for use in a GUI / WM...
Implementing a special purpose image compressor designed to allow random access to blocks of pixels (without needing to decompress the whole image), and incremental modification; without the loss of fidelity inherent in color-cell formats. Intended for use in a GUI / WM...
OK, it seems my X profile is back, sorta, but in some sort of unknown state. It appears as it was when I was last on there, but seemingly I am not able to log into it (log-in via my phone appears to work, but takes me to the alternate hacked account...).
August 20, 2026 at 2:36 AM
OK, it seems my X profile is back, sorta, but in some sort of unknown state. It appears as it was when I was last on there, but seemingly I am not able to log into it (log-in via my phone appears to work, but takes me to the alternate hacked account...).
Random:
I have decided to move my CPU core from MIT to CERN-OHL-P terms. Also probably my ISA docs as well (vs the makeshift recent "UsagePolicy" file, both have a similar idea here...).
Also, would be nice if people would stop trying to hack into my stuff... No one really bothered before...
I have decided to move my CPU core from MIT to CERN-OHL-P terms. Also probably my ISA docs as well (vs the makeshift recent "UsagePolicy" file, both have a similar idea here...).
Also, would be nice if people would stop trying to hack into my stuff... No one really bothered before...
August 19, 2026 at 9:17 PM
Random:
I have decided to move my CPU core from MIT to CERN-OHL-P terms. Also probably my ISA docs as well (vs the makeshift recent "UsagePolicy" file, both have a similar idea here...).
Also, would be nice if people would stop trying to hack into my stuff... No one really bothered before...
I have decided to move my CPU core from MIT to CERN-OHL-P terms. Also probably my ISA docs as well (vs the makeshift recent "UsagePolicy" file, both have a similar idea here...).
Also, would be nice if people would stop trying to hack into my stuff... No one really bothered before...
Well, disasters come in pairs sometimes:
My mom's first bunny dies, so does my PC's PSU;
My mom's second bunny dies, and my X account gets hacked, and (possibly related) some of the worst insomnia I have experienced in a while.
Also all the heat sucks and is harming all the trees and grass...
My mom's first bunny dies, so does my PC's PSU;
My mom's second bunny dies, and my X account gets hacked, and (possibly related) some of the worst insomnia I have experienced in a while.
Also all the heat sucks and is harming all the trees and grass...
August 18, 2026 at 4:01 PM
Well, disasters come in pairs sometimes:
My mom's first bunny dies, so does my PC's PSU;
My mom's second bunny dies, and my X account gets hacked, and (possibly related) some of the worst insomnia I have experienced in a while.
Also all the heat sucks and is harming all the trees and grass...
My mom's first bunny dies, so does my PC's PSU;
My mom's second bunny dies, and my X account gets hacked, and (possibly related) some of the worst insomnia I have experienced in a while.
Also all the heat sucks and is harming all the trees and grass...
Well, RIP my Twitter/X account... Seems I likely fell victim to social-engineering / hacking... Would have thought I would have been smarter, but alas... RIP to posting status updates and mostly just talking to Grok I guess...
August 17, 2026 at 2:49 PM
Well, RIP my Twitter/X account... Seems I likely fell victim to social-engineering / hacking... Would have thought I would have been smarter, but alas... RIP to posting status updates and mostly just talking to Grok I guess...
FWIW: Recently had thrown together a makeshift low-res graphics editor focusing mostly on pixel editing and low-res indexed-color graphics. Minimal UI, but had gotten it to a state of basic functionality. Has a funky copy/paste mechanism that can be used as a bulk pattern fill via self-overlap...
July 9, 2026 at 5:03 AM
FWIW: Recently had thrown together a makeshift low-res graphics editor focusing mostly on pixel editing and low-res indexed-color graphics. Minimal UI, but had gotten it to a state of basic functionality. Has a funky copy/paste mechanism that can be used as a bulk pattern fill via self-overlap...