November 2003 - OpenBIOS - mail.coreboot.org

Dictionary Compression vs eXecute In Place
by Stefan Reinauer Nov. 20, 2003

Nov. 20, 2003

Hi,. since the openbios dictionary is growing and growing as it becomes more complete, I've looked at different ways to optimize the dictionary handling. There's two methods of "safing" memory: compression and execute in place. 1) Compression Some numbers, taking 32bit dictionary (x86) method | size/bytes ---------------+------------- uncompressed | 62668 nrv2b | 22466 gzip | 20982 bzip2 | 19388 The current kernel is slightly below 8k (8172 bytes) * pro: small(er) flash parts can be used. * con: code has to be decompressed to memory first, higher memory usage. 2) XIP (eXecute In Place) If not compressing the dictionary, it could be changed so that all but the readwriteable data can be executed directly from ROM. This would decrease the use of RAM in embedded systems noticeably, but it is also slower on about every system. * pro: extremely low memory usage ( < code size) * con: slow execution. Looking at the amount of code this is about, (2) is pretty much neglectable for most systems whereas (1) is an interesting option. Comments? Stefan

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Device Tree and FCode evaluator
by Stefan Reinauer Nov. 19, 2003

Nov. 19, 2003

Hi, the current openbios cvs contains a lot of new code from the device interface. We have a device tree now and can evaluate FCode on device option ROMs. Now OpenBIOS lacks a whole lot of Open Firmware "support packages" like the deblocker, tftp booting for network interfaces, the terminal emulator, filesystem support, etc etc. And of course: OpenBIOS needs device drivers! Open Source drivers, vendor FCode, everything that helps OpenBIOS to support a wide range of hardware ;-) I started setting the framework for the support packages in openbios/forth/packages, find one source file per support package. Also, there's an example fcode driver coming with the QT-Plugin of the openbios kernel: openbios/kernel/plugins/plugin_qt/qt_rom.fs I'll attach a simple example to this mail that executes the QT Plugins FCode. To test it, do: ~/openbios $ make ~/openbios $ make rungui < device-example.fs It will use the FCode binary built into the plugin to initialize the virtual graphics hardware and output a character. Next thing I'm going to work on is to finish the terminal emulator and other support packages, then facing the client interface code to finally boot an operating system For the client interface it should make sense to reuse a lot of existing code, i.e filesystem drivers (GRUB), elf booting (Filo, LinuxBIOS), etc. by using the calling interfaces from forth to C and the other way round. Stefan

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APIC 82489 datasheet
by fizjm＠univ.gda.pl Nov. 18, 2003

Nov. 18, 2003

Hi all, Does anyone have a datasheet for APIC 82489 chip? I could not find it anywhere.. I understand that this chip is a replacement for I8259 used till now as an interrupt controller on a PC/AT. I would like to learn more, and to play with extra IRQs (IRQ15+) it provides. Most modern PC chipsets support this chip am I correct? Thanks for help. Janusz

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Re: lib.fs missing in CVS
by Stefan Reinauer Nov. 10, 2003

Nov. 10, 2003

Hi, good news. The fcode evaluator is working. init-fcode-table probably needs some work (table.fs) since iirc a child node should be able to see fcode words defined by the parent. At least byte-load now cleanly creates an fcode lookup table in alloc-mem'ed memory and frees it after evaluation which it did not do at all before. The verbosity of the fcode evaluator can be switched on/off with the value ?fcode-verbose. This also enables warnings about missing words during fcode table initialization. The latest code is in CVS. Test with following test-fcode.fs: ------------- 10 30 pci-l@ /n 8 = if 10 34 pci-l@ 20 << or then 0 byte-load bye ------------ After doing a make in the toplevel, do a make rungui < test-fcode.fs bye, Stefan

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[PATCH] variable instatiation support
by Samuel Rydh Nov. 3, 2003

Nov. 3, 2003

Hi, This patch adds variable instantiation support. It is intended to be used for device node instantiation. Some implementational details: - all template data is put into the dictionary. The thought behind this is to make it possible to put both methods and template data in a single wordlist. - instantiated variables are stored in a continuous block of memory (in contrast to the template data which is spread out in the dictionary). A small example file is also attached to this e-mail. Regards, /Samuiel

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