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by hermanhermitage
Sat Mar 01, 2014 8:58 pm
Forum: Bare metal, Assembly language
Topic: GPU specs
Replies: 4
Views: 1876

Re: GPU specs

Hehe... Noli equi dentes inspicere donati
by hermanhermitage
Sat Feb 22, 2014 1:35 am
Forum: C/C++
Topic: GPU Processing API
Replies: 124
Views: 45125

Re: GPU Processing API

or simply because its much harder to do than anyone assumes, or is willing to admit.... :mrgreen: This. It is a hell of a lot of very very difficult work. There, I admitted it. Not necessarily meeting the open source criteria, but if the OpenGL ES driver was extended to include glTransformFeedbackV...
by hermanhermitage
Sat Feb 15, 2014 4:22 am
Forum: Graphics, sound and multimedia
Topic: GPU_FFT and audio processing? (Guitar FX thread)
Replies: 7
Views: 6790

Re: GPU_FFT and audio processing? (Guitar FX thread)

I'm not sure about the hardware side of things (getting audio signal into and out of pi). But in terms of access to DSP like accelerators (VPU and QPU), I think i've got a reasonable handle on developing that kind of code on the RPi (I've just uploaded a mini assembler for QPU at https://github.com/...
by hermanhermitage
Tue Feb 11, 2014 7:40 am
Forum: Bare metal, Assembly language
Topic: Defining addresses and bit-fields with structs
Replies: 12
Views: 3211

Re: Defining addresses and bit-fields with structs

Apart from the portability issues, bitfields can make program logic rather unclear by hiding the sequence of read-modify-write involved. When accessing hardware registers you usually want transparency on the bus traffic. Hardware level programming you tend to want things clear and explicit. Where bi...
by hermanhermitage
Mon Feb 10, 2014 12:26 am
Forum: C/C++
Topic: GPU Processing API
Replies: 124
Views: 45125

Re: GPU Processing API

I've started putting some QPU samples at https://github.com/hermanhermitage/videocoreiv-qpu/tree/master/qpu-tutorial There's enough there to get results back out of the QPUs. I really need to add a VPM read example, and a working assembler (or something like Dynasm) for this to be useful to most peo...
by hermanhermitage
Wed Jan 15, 2014 1:20 am
Forum: Graphics programming
Topic: fbturbo - dma hardly ever gets used?
Replies: 45
Views: 10378

Re: fbturbo - dma hardly ever gets used?

I'm all for pitching in with some VPU code. I've glanced at X11 in the past but it felt like too steep a mountain to climb with rather limited time here. Are there some bulk asynchronous commands we can implement? I got the feeling most X applications had devolved over the years into client side ren...
by hermanhermitage
Wed Jul 24, 2013 5:18 am
Forum: C/C++
Topic: GPU Processing API
Replies: 124
Views: 45125

Re: GPU Processing API

For anyone interested, I've begun documenting the Shader Processor portion of the RaspberryPi at https://github.com/hermanhermitage/videocoreiv-qpu. I've sat on this for a while, but it feels like the time is right now. Basically the shader processor (QPU) is the floating point monster inside the Ra...
by hermanhermitage
Tue May 28, 2013 11:58 pm
Forum: C/C++
Topic: GPU Processing API
Replies: 124
Views: 45125

Re: GPU Processing API

How comes there is still no open source driver to do GPU computing? ... It just requires hands on deck. Well, I'm glad to hear that but... what skills are required to provide some of the needed help ? Must one be top notch asm programmer/coder to be able to join the working force ? Is there some de...
by hermanhermitage
Sun May 26, 2013 12:13 am
Forum: C/C++
Topic: GPU Processing API
Replies: 124
Views: 45125

Re: GPU Processing API

How comes there is still no open source driver to do GPU computing? Probably business reasons, and BRCM not having their own suitable implementation. We the community can produce such a driver if everyone steps up and contributes. So roll up those sleeves and please throw us some of your time. Righ...
by hermanhermitage
Thu Jan 31, 2013 7:52 pm
Forum: C/C++
Topic: VFP SIMD Instructions, howto?
Replies: 9
Views: 5084

Re: VFP SIMD Instructions, howto?

hermanhermitage wrote: ...VFPv1...
Should read vfpv2 for arm v6

You could try -O2 -ftree-vectorize -mfpu=vfp on a modern GCC, but id be surprised if it generates any vectorization or if it does whether there are any perf gains.
by hermanhermitage
Thu Jan 31, 2013 6:44 pm
Forum: C/C++
Topic: VFP SIMD Instructions, howto?
Replies: 9
Views: 5084

Re: VFP SIMD Instructions, howto?

The document referenced below describes the VFP SIMD instructions and control registers and when I do a cat /proc/cpuinfo I see VFP explicitly mentioned. Please check if I got the core name right. So I assume that the V in VFP means vector and that VFP might be a predecessor to NEON. http://infocen...
by hermanhermitage
Thu Jan 31, 2013 9:26 am
Forum: C/C++
Topic: VFP SIMD Instructions, howto?
Replies: 9
Views: 5084

Re: VFP SIMD Instructions, howto?

raspberry pi doesn't have neon instruction set. it may be possible to use video core kernels to implement simd instructions. definitely non trivial though! Yes as you say, ARM v6 has no neon - the SIMD covers packed 32 bit operations see http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.d...
by hermanhermitage
Tue Jan 22, 2013 12:13 pm
Forum: General discussion
Topic: GPGPU on the R-PI.
Replies: 75
Views: 52701

Re: GPGPU on the R-PI.

This would be a lot of work for little more than the learning experience. As good as the VideoCoreIV is for its size, it will not beat a desktop PC graphics card for GPGPU on flops/dollar. It likely will not beat a laptop GPU chip on flops/watt either. If you want to build an efficient compute plat...
by hermanhermitage
Thu Jan 17, 2013 10:30 am
Forum: Bare metal, Assembly language
Topic: GPU access or how the architeture of CPU/GPU SoC looks like?
Replies: 6
Views: 2302

Re: GPU access or how the architeture of CPU/GPU SoC looks l

I have very much enjuoyed playing with the VideoCore processors. I can not find any information on how to get anything out to the disply. Has anyone figured this out yet? If so is there any documentation on this anywhere yet? With no BOOTCODE.BIN there are no MailBoxes to simplify this. Your best b...
by hermanhermitage
Wed Jan 16, 2013 12:04 am
Forum: Other
Topic: STAROS - Atari ST (GEM+TOS)
Replies: 23
Views: 11226

Re: STAROS - Atari ST (GEM+TOS)

Remember the VC4 is clocked at 250Mhz, whilst the Arm is up to 1GHz. So you will get better performance out of the Arm since you are unlikely to be able to use the vector cores in any useful way to emulate 68020 instructions. The vectors cores multiply up the performance on the GPU (16 way SIMD vec...
by hermanhermitage
Sat Jan 12, 2013 2:32 am
Forum: Bare metal, Assembly language
Topic: GPU access or how the architeture of CPU/GPU SoC looks like?
Replies: 6
Views: 2302

Re: GPU access or how the architeture of CPU/GPU SoC looks l

I have been searching on internet for overview of BCM SoC of raspberry pi but can't find something I've put relevant public diagrams (from Broadcom's patents) here: https://github.com/hermanhermitage/videocoreiv/wiki/VideoCore-IV---BCM2835-Overview Will add more information over time. Go up a few l...
by hermanhermitage
Thu Nov 29, 2012 3:54 pm
Forum: Bare metal, Assembly language
Topic: start.elf - what's really needed for bare metal OS?
Replies: 5
Views: 8738

Re: start.elf - what's really needed for bare metal OS?

> You can delete start.elf (and fixup.dat) if you set gpu_mem=16 in config.txt. > It uses start_cd.elf which is 550K and doesn't include support for GL/VG/OpenMAX etc. I don't have fixup.dat or start_cd.elf. All I have is: bootcode.bin, loader.bin, start.elf, config.txt and my kernel.img. > The 2MB...
by hermanhermitage
Thu Nov 29, 2012 2:58 pm
Forum: Bare metal, Assembly language
Topic: start.elf - what's really needed for bare metal OS?
Replies: 5
Views: 8738

Re: start.elf - what's really needed for bare metal OS?

So now I'm looking at start.elf and wondering why I need 2Mb to flash the screen in pretty colours for about 1/10th of a second before my OS takes over. Has anyone looked at removing/stripping down start.elf? start_cd.elf is 550kb for 16MB split. The 2MB start.elf contains a multitasking kernel (Th...
by hermanhermitage
Wed Nov 28, 2012 10:33 am
Forum: Android
Topic: Project: Android JB 4.1 with Hardware acceleration
Replies: 126
Views: 96454

Re: Project: Android JB 4.1 with Hardware acceleration

Mostly right! Only error is that Broadcom are working very hard on Android! Keep up the work! Think how yummy a little tablet or lapdock that could take a RPi insert would be! (ok ok, it would probably need a slim line version but wouldnt it be great to have children using a device more flexible th...
by hermanhermitage
Sat Nov 17, 2012 2:56 am
Forum: Other projects
Topic: MIPI DSI general documentation
Replies: 2
Views: 1652

Re: MIPI DSI general documentation

Hello, I´ve stumbled upon some MIPI DSI references and documentation pdfs online, now I don´t know if that information could be helpful to get the MIPI DSI port workable on the Pi by some reverse engineering god, but no need to hide it ;) Raspbook, thanks for sharing. Good background which will mak...
by hermanhermitage
Sat Nov 10, 2012 10:33 pm
Forum: Off topic discussion
Topic: New ARM board: cubieboard
Replies: 21
Views: 10792

Re: New ARM board: cubieboard

Do Cubieboard have their own forum, or does everyone just post here about it???? ;) They have a google group - https://groups.google.com/forum/m/#!forum/ But I'm sure there are a few people reading the forums who are interested in both. indicates there might be room in the market here for a $45 mod...
by hermanhermitage
Wed Oct 31, 2012 10:44 am
Forum: Gaming
Topic: Best Emulators for Pi
Replies: 24
Views: 22944

Re: Best Emulators for Pi

welshy wrote:As a Retro Game fanatic I have...
Welshy... wow amazing post - thanks for taking the time to do this and sharing with all of us here.
by hermanhermitage
Mon Oct 29, 2012 10:55 am
Forum: C/C++
Topic: GPU Processing API
Replies: 124
Views: 45125

Re: GPU Processing API

So I have read when the Pi boots up it uses the GPU to load the Bootloader. What address does the GPU search for to load the Bootloader? The GPU uses an internal bootroom at 0x80000000 from memory (dont have the addresses handy here). Sorry thats 0x6000000 to 0x60007fff. 0x60008000 is either cache ...
by hermanhermitage
Mon Oct 29, 2012 3:04 am
Forum: Bare metal, Assembly language
Topic: Bare Metal ZX81 emulator
Replies: 30
Views: 9377

Re: Bare Metal ZX81 emulator

Each library needs OPEN, CLOSE, TXRX functions. TXRX accepts a command string, the contents of which are the command language of the interface. So construction of the command language is the abstraction. In fact one function call TXRX is needed, and open and close can be done on first and last use....
by hermanhermitage
Mon Oct 29, 2012 1:23 am
Forum: Bare metal, Assembly language
Topic: Bare Metal ZX81 emulator
Replies: 30
Views: 9377

Re: Bare Metal ZX81 emulator

of course resource management (task, interrupt, processes, memory) is a little tricky to do in a neutral manner. Any takers? I won't take to the coding, but you could do worse than virtual machines for this king of stuff. Not what I'm suggesting at all. Instead I'm suggesting a policy agnostic libr...

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