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by bzt
Mon Jun 24, 2019 6:36 pm
Forum: Bare metal, Assembly language
Topic: Raspberry Pi 4
Replies: 3
Views: 186

Raspberry Pi 4

Hi Guys, This is so cool https://www.raspberrypi.org/blog/raspberry-pi-4-on-sale-now-from-35/ It looks like almost all my wishes come true :-) ARMv8a (note the "a"), 4G RAM, super fast USB3, PCIe, and finally the legacy VC dropped, and Raspbian switched to Mesa! It is time for me to finally start pl...
by bzt
Sat Jun 15, 2019 1:05 pm
Forum: Bare metal, Assembly language
Topic: A little Progress on my little OS Project:
Replies: 23
Views: 1417

Re: A little Progress on my little OS Project:

Hi, I'm afraid we have hijacked the topic, sorry DavidS. I'm still very curious about your source code if you don't mind. @LdB: Okay, if you say so, I believe you. You have more experience with VC and OpenGL than I have. As for the curves, do not calculate them. Convert them into series of lines wit...
by bzt
Sat Jun 15, 2019 12:54 pm
Forum: Bare metal, Assembly language
Topic: Loading DWARF info in the kernel memory
Replies: 3
Views: 225

Re: Loading DWARF info in the kernel memory

Hi, You question is somewhat vague, because there's no ELF loader to load a kernel. There's a step with objconv, when you convert the ELF into IMG by cropping out the text segment. Therefore you have to put the debug info into the text segment. For that, you have two options: 1. put your debug info ...
by bzt
Fri Jun 14, 2019 5:38 pm
Forum: Bare metal, Assembly language
Topic: A little Progress on my little OS Project:
Replies: 23
Views: 1417

Re: A little Progress on my little OS Project:

Hi, I think there's nothing wrong with doubles, the GPU is using float point numbers after all. I see no point in struggling with integers if you want to render the glyph on the GPU at the end. My font library uses a CPU only rasterizer, therefore it made sense for me to use integer arithmetic only....
by bzt
Fri Jun 14, 2019 1:09 pm
Forum: Bare metal, Assembly language
Topic: A little Progress on my little OS Project:
Replies: 23
Views: 1417

Re: A little Progress on my little OS Project:

Cheers I like that a lot let me do some testing. If you are into you maths I have another one for you to have a crack at :-) Yeah, at the university I've learned to be a software oriented mathematician, so we can say that :-) As you know what you really want to do is fill the outline glyph not draw...
by bzt
Thu Jun 13, 2019 5:00 pm
Forum: C/C++
Topic: code for UART comm from Pi to Arduino hangs up
Replies: 46
Views: 1770

Re: code for UART comm from Pi to Arduino hangs up

Hi,

I'm sorry if I sounded rude, I didn't meant to. I'm glad to hear that you have solved your issue!

Cheers,
bzt
by bzt
Thu Jun 13, 2019 4:42 pm
Forum: Bare metal, Assembly language
Topic: A little Progress on my little OS Project:
Replies: 23
Views: 1417

Re: A little Progress on my little OS Project:

Hi, @DavidS: sounds really interesting what you have accomplished! Would it be possible to take look at your source? Your github repo only contains a README.md, that's all. Makes you wonder why people want to use OpenGL for Desktops GUIs when OpenVG is easier. For portability, I guess. At least I ca...
by bzt
Tue Jun 11, 2019 12:43 pm
Forum: C/C++
Topic: code for UART comm from Pi to Arduino hangs up
Replies: 46
Views: 1770

Re: code for UART comm from Pi to Arduino hangs up

With respect, I think you are the one who's missing something. both for the Arduino and for the PC there are simple "high-level" UART read/write functions available Reading and writing from a file descriptor is the most abstract, highest level possible. The UNIX philosophy (and therefore Linux) abst...
by bzt
Mon Jun 10, 2019 2:06 pm
Forum: C/C++
Topic: code for UART comm from Pi to Arduino hangs up
Replies: 46
Views: 1770

Re: code for UART comm from Pi to Arduino hangs up

that looks like what wiringSerial serialGetchar(fd) is supposed to do, but that fails, so what is the advantage? You can rule out one component, and replace with one that known to be working on many architectures and OSes (Raspbian included). where is the timeout handling, the buffer handling, perh...
by bzt
Sun Jun 09, 2019 6:31 pm
Forum: C/C++
Topic: code for UART comm from Pi to Arduino hangs up
Replies: 46
Views: 1770

Re: code for UART comm from Pi to Arduino hangs up

All I would need is a simple-to-use function SerialReadString(std::string rcvString, int maxlen, int fd); Is std::string SerialReadString(int maxlen, int fd) { char buff[maxlen]; read(fd, &buff, maxlen); return new std::string(&buff); } and void SerialWriteString(std::string sndString, int len, int...
by bzt
Sun Jun 09, 2019 5:57 pm
Forum: C/C++
Topic: Trouble with GCC compiling
Replies: 9
Views: 385

Re: Trouble with GCC compiling

Hi, First off, thank you for looking into this and being patient with me. I really don't understand libraries that well. That's simple. There're two kinds of libraries: statically linked and dynamically linked. Statically linked libraries have the extension .a (stands for object archive), and you li...
by bzt
Sun Jun 09, 2019 5:13 pm
Forum: C/C++
Topic: code for UART comm from Pi to Arduino hangs up
Replies: 46
Views: 1770

Re: code for UART comm from Pi to Arduino hangs up

thanks for your comments, but all that is far beyond my skills, I just can handle a little bit of wiringPi, even pigpio or above all native UART or termios are far too complicated (and what the hell is PL011 or MniAUX?) : It is not complicated (see my example) just looks like it :-) Has three parts...
by bzt
Sun Jun 09, 2019 12:23 pm
Forum: C/C++
Topic: code for UART comm from Pi to Arduino hangs up
Replies: 46
Views: 1770

Re: code for UART comm from Pi to Arduino hangs up

tbh, termios looks far too complicated to me and I don't have any experience or skills using that. It is not complicated. Looks weird, I give you that, that's why I gave you an example. You open a file, you use some 10-12 lines of magic on the fd, and there you go. OTOH I thought that wiringPi/wiri...
by bzt
Sat Jun 08, 2019 2:49 pm
Forum: C/C++
Topic: code for UART comm from Pi to Arduino hangs up
Replies: 46
Views: 1770

Re: code for UART comm from Pi to Arduino hangs up

Hi, I'm not sure about your problem, but why don't you use termios on RPi side? I have implemented serial communications with it many times to many different UARTs (including microcontrollers and industrial PLCs alike), and it have never failed me, and never lost sync not even over a long period of ...
by bzt
Wed Jun 05, 2019 1:43 pm
Forum: Bare metal, Assembly language
Topic: Displaying fonts
Replies: 2
Views: 430

Re: Displaying fonts

You're welcome! Please keep me posted how it goes! Sounds like a great project! To help you with that: in outline mode, ssfn_render() will return line paths (all curves and splines are converted to series of lines). Coordinates are scaled up to 255 x 255 (which is quite a big character even for Full...
by bzt
Wed Jun 05, 2019 1:05 pm
Forum: Bare metal, Assembly language
Topic: Loading the kernel without the SD card
Replies: 5
Views: 1470

Re: Loading the kernel without the SD card

Hi, In theory endianess doesn't matter since the code reads bytes and concatenates them afterwards using bit shifts. But the size can arrive in the wrong order in the first place of course. TBH, I've never tried the Java sender, as I have a general dislike about Java ever since I haven't got paid fo...
by bzt
Tue May 28, 2019 1:56 am
Forum: Bare metal, Assembly language
Topic: Displaying fonts
Replies: 2
Views: 430

Displaying fonts

Hi, I saw in this topic that others may be interested in my little project. I wanted to display UTF-8 strings in my bare metal app. At first glance it doesn't seem difficult, right? But if you dig deeper, you'll see how far that rabbit hole goes... The first problem is bitmap fonts. 8x16 is perfectl...
by bzt
Mon Apr 29, 2019 9:59 am
Forum: Networking and servers
Topic: Nextcloud: help to convert database from SQLite to MySQL
Replies: 6
Views: 436

Re: Nextcloud: help to convert database from SQLite to MySQL

Hi, Just dump your database from sqlite and import into mysql. That's the simplest way. You'll only need to edit autoincrement fields (if you have those) because the two db uses a slightly different syntax for them, but that's all. echo "select * from X" | sqlite dbfile >dump.X.sql then edit the sch...
by bzt
Fri Apr 19, 2019 10:39 am
Forum: Bare metal, Assembly language
Topic: Low level RPI programming
Replies: 6
Views: 811

Re: Low level RPI programming

Welcome to the bare metal programming forum! So my question is this: is there a way to program a raspberry pi with assembler without installing an OS? Yes, that's exactly what this forum is about :-) You can find plenty of Assembly here, without any OS requirement. (I'd suggest to use the keywords "...
by bzt
Fri Apr 19, 2019 10:35 am
Forum: Bare metal, Assembly language
Topic: Best way to synchronize timers?
Replies: 1
Views: 257

Re: Best way to synchronize timers?

Hi, I think the most efficient solution is to issue WFE on the application cores, and use SEV in the local timer ISR on the main core. That's the solution with the smallest latency possible. The downside is, you can only use one randevous point like this, which is good if you have only this single 1...
by bzt
Thu Apr 11, 2019 10:34 am
Forum: Beginners
Topic: [Solved] How to turn off Raspberry with a keyboard ?
Replies: 9
Views: 492

Re: How to turn off Raspberry with a keyboard ?

Hi,

You could use [Alt]+[SysRq] and then [o].

If your keyboard does not provide a key with scancode for SysRq, you can try to configure the Magic SysRq. Chromebook keyboards use [Alt]+[VolumeUp] or [Alt]+[F10] for example.

Cheers,
bzt
by bzt
Tue Apr 09, 2019 10:36 pm
Forum: Bare metal, Assembly language
Topic: Why can't I run 32-bit kernels on QEMU's RPi3?
Replies: 6
Views: 500

Re: Why can't I run 32-bit kernels on QEMU's RPi3?

Hi, Thank you very much for your answer, everything is much clearer now. Do you think it would be possible to have the 32-bit boot process while still using cortex-A53 instead of downgrading to cortex-A7? I don't think it will be possible soon. When I first submited my patch, I've created a separate...
by bzt
Tue Apr 09, 2019 3:44 pm
Forum: Bare metal, Assembly language
Topic: Why can't I run 32-bit kernels on QEMU's RPi3?
Replies: 6
Views: 500

Re: Why can't I run 32-bit kernels on QEMU's RPi3?

Hi, Hello, On a real Raspberry Pi 3, you can run a 32-bit kernel thanks to aarch64 32-bit retrocompatibility. However when I run a 32-bit kernel using raspi3 machine on QEMU, it just doesn't run, I have to use the raspi2 machine. Any idea on why? Is there a problem with the retrocompatibility of QEM...
by bzt
Thu Apr 04, 2019 12:08 pm
Forum: Bare metal, Assembly language
Topic: Circle - C++ bare metal environment (with USB)
Replies: 177
Views: 47950

Re: Circle - C++ bare metal environment (with USB)

Hi First, Circle is getting better and better, well done! I've linked it from my tutorials just in case someone's looking for a bare metal C++ library. :-) But back when I tried to go from C to C++ (DOS C era) they started this thing called Hungarian notation, totally put me off C++. Of course, you ...
by bzt
Sun Mar 31, 2019 8:34 pm
Forum: C/C++
Topic: [TCP] Server/client non blocking: missing sys/event.h?
Replies: 1
Views: 1320

Re: [TCP] Server/client non blocking: missing sys/event.h?

Hi, Auch, that's a terrible example with lots of unecessary dependencies. TCP communication is a lot simpler than that, try one of these: http://my.fit.edu/~vkepuska/ece3551/ADI_Speedway_Golden/Blackfin%20Speedway%20Manuals/LwIP/socket-api/tcp-cli-serv.html (lwip lib) https://www.binarytides.com/ser...

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