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by david.given
Sat Jul 01, 2017 10:26 am
Forum: Raspbian
Topic: Does Raspian include jessie-backports?
Replies: 8
Views: 1902

Re: Does Raspian include jessie-backports?

Who curates the package list (because there's more in Raspbian than just the packages from jessie)?
by david.given
Sat Jul 01, 2017 10:19 am
Forum: Raspbian
Topic: Does Raspian include jessie-backports?
Replies: 8
Views: 1902

Re: Does Raspian include jessie-backports?

Thanks, but that doesn't really answer my question...

Does Raspbian jessie include jessie-backports? Will packages pushed to jessie-backports get automatically included in Raspbian, either in the prebuilt image or via updates?
by david.given
Thu Jun 29, 2017 9:40 pm
Forum: Raspbian
Topic: Does Raspian include jessie-backports?
Replies: 8
Views: 1902

Re: Does Raspian include jessie-backports?

Stretch does indeed have a less terrible version, and that's the one I'm backporting (as per the Debian instructions). But I'm not sure that simply writing off Raspbian jessie is an option. Even after stretch is released, people are going to be using Raspbian jessie for years, and relying on automat...
by david.given
Thu Jun 29, 2017 8:47 pm
Forum: Raspbian
Topic: Does Raspian include jessie-backports?
Replies: 8
Views: 1902

Does Raspian include jessie-backports?

Do Raspbian images automatically contain the latest versions of packages in jessie-backports? The context is: I am the author of a simple terminal mode word processor, WordGrinder (<plug> http://cowlark.com/wordgrinder/ </plug>). It runs well on very low-rent hardware, including the Raspberry Pi. I ...
by david.given
Sat Jan 16, 2016 9:27 pm
Forum: Bare metal, Assembly language
Topic: Setting up modes?
Replies: 8
Views: 3960

Re: Setting up modes?

A bit belated, but the cps instruction is your friend: cps #0x10 ; Now we're in user mode! You can also use it to turn interrupts on or off: cpsie if ; Enable irq and fiq interrupts cpsid if ; ...and disable them And do both: cpsie if, #0x10 ; Interrupts on, go to user mode When writing exception ha...
by david.given
Mon Dec 28, 2015 3:06 pm
Forum: Bare metal, Assembly language
Topic: Debugging via JTAG with a Bus Pirate
Replies: 4
Views: 1843

Re: Debugging via JTAG with a Bus Pirate

The Bus Pirate is unusually weird over other JTAG adapters (not least of which is that its connectors don't have the traditional JTAG labels).

I know about JTAG; I want to know whether anyone has tried THIS SPECIFIC COMBINATION OF HARDWARE before I start doing potentially dangerous experimentation.
by david.given
Sun Dec 27, 2015 5:20 pm
Forum: Bare metal, Assembly language
Topic: Platform detection
Replies: 14
Views: 2620

Re: Platform detection

That's pretty neat --- on the Pi 2, there'll be RAM mapped at 0x20000000 so the read will succeed (rather than throwing an exception). I reckon I can make that work. Thanks!
by david.given
Thu Dec 24, 2015 5:51 pm
Forum: Bare metal, Assembly language
Topic: Debugging via JTAG with a Bus Pirate
Replies: 4
Views: 1843

Re: Debugging via JTAG with a Bus Pirate

Thanks, but I am specifically asking about the Bus Pirate here --- it's rather different from other JTAG adapters and need its own setup.

Has anyone ever used one on the Raspberry Pi?
by david.given
Wed Dec 16, 2015 11:02 pm
Forum: Bare metal, Assembly language
Topic: Platform detection
Replies: 14
Views: 2620

Re: Platform detection

Of course, you can't make a mailbox call until you know the address of the peripheral space.

Are there any good strategies for detecting this?
by david.given
Sat Dec 12, 2015 8:22 pm
Forum: General discussion
Topic: raspbery pi simulator
Replies: 4
Views: 2976

Re: raspbery pi simulator

There's a patched qemu that simulates Raspberry Pi hardware here: https://github.com/0xabu/qemu/tree/raspi Documentation here: https://github.com/0xabu/qemu/wiki It works well enough to boot Windows 10; Raspbian sort of works. I'm using it for bare metal work. It's missing a lot of the more interest...
by david.given
Thu Dec 10, 2015 11:16 pm
Forum: Bare metal, Assembly language
Topic: RPi B+ Coprosser 15 register settings upon start up
Replies: 1
Views: 3081

Re: RPi B+ Coprosser 15 register settings upon start up

That's really useful --- thanks!

As the A and the other Bs have the same processor core, they should all have the same settings, right? How different is it likely to look for the Pi2?
by david.given
Thu Dec 10, 2015 11:13 pm
Forum: Bare metal, Assembly language
Topic: VideoCore4 programming resources
Replies: 0
Views: 857

VideoCore4 programming resources

A couple of years ago I wrote this. It occurs to me I probably forgot to tell anyone here about it. http://cowlark.com/piface It's a boot loader which runs directly on the VPU, replacing the existing bootcode.bin. It supports SD card access, poorly, and XMODEM up and download. It unfortunately does ...
by david.given
Thu Dec 10, 2015 10:26 pm
Forum: Bare metal, Assembly language
Topic: Debugging via JTAG with a Bus Pirate
Replies: 4
Views: 1843

Debugging via JTAG with a Bus Pirate

Has anyone ever gotten JTAG debugging working via a Bus Pirate in JTAG interface mode? I have a Pi 2 (and a Pi 1, but it's one of the original models which doesn't expose one of the JTAG pins, so that's not much use to me). Being able to debug via JTAG would be exceptionally useful to me. It doesn't...
by david.given
Thu Dec 10, 2015 3:57 pm
Forum: Bare metal, Assembly language
Topic: What to flush when updating the page mappings
Replies: 2
Views: 734

Re: What to flush when updating the page mappings

The answer there was a maybe. I was hoping someone here would be more likely to know. It actually turns out that the OS I'm porting only does kernel->user and user->kernel copies, so I don't need to have multiple processes mapped at once, which means cache coherency is no longer a problem. But I *wo...
by david.given
Sat Dec 05, 2015 11:28 pm
Forum: Bare metal, Assembly language
Topic: What to flush when updating the page mappings
Replies: 2
Views: 734

What to flush when updating the page mappings

I'm writing a toy operating system for the Pi. I want to use basic memory mapping features, mainly so I can swap code in and out of a particular virtual address for easy task switching. I'm intending to use the 1MB sections because they look pretty simple and they're big enough that I only need to c...

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