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by jahboater
Tue Apr 25, 2017 7:24 am
Forum: Advanced users
Topic: Raspbian SD card image
Replies: 4
Views: 984

Re: Raspbian SD card image

Also try typing "sync" before ejecting the card.
by jahboater
Mon Apr 24, 2017 5:45 pm
Forum: Troubleshooting
Topic: Heat issues with Pi3
Replies: 4
Views: 869

Re: Heat issues with Pi3

jamesh, i have tried two differnt pi's. I have it sitting behind a monitor on a shelf. Must be airflow Try placing the board on edge with the heat sink fins aligned vertically (outside of a case obviously). That improved convection airflow worked for me even for the nastiest stress test. Normally t...
by jahboater
Mon Apr 24, 2017 3:28 pm
Forum: C/C++
Topic: New Gcc 7.1, his build sources result success with B model A
Replies: 52
Views: 7900

Re: New Gcc 7.1, his build sources result success with B mod

Hi If you look mirror you will see that only one snapshot (7) existing version gcc-7-20170420, it's the version approved 7.1, but you can wait it moved named 7.1 on the mirrors if you prefer ... Regards I think this snapshot is RC1 gcc -v shows "gcc version 7.0.1 20170420 (prerelease) (GCC)". But t...
by jahboater
Mon Apr 24, 2017 12:18 pm
Forum: C/C++
Topic: New Gcc 7.1, his build sources result success with B model A
Replies: 52
Views: 7900

Re: New Gcc 7.1, his build sources result success with B mod

I know gcc 7.1 is due for release around the end of this week, but what is this post about?
by jahboater
Sat Apr 22, 2017 6:26 pm
Forum: Other programming languages
Topic: 64 bit multiplication segmentation error
Replies: 24
Views: 2973

Re: 64 bit multiplication segmentation error

Alextek117 wrote: So all I had to do was to add '!'???
In assembler little things like that are crucial!
It means add the number of bytes written to the destination address register so that the next write starts in the right place.
Cool!

and please read the ARM documentation for all instructions you want to use.
by jahboater
Sat Apr 22, 2017 6:13 pm
Forum: Other programming languages
Topic: 64 bit multiplication segmentation error
Replies: 24
Views: 2973

Re: 64 bit multiplication segmentation error

Alextek117 wrote: So how would I travel to the next position if I want to store the results in an array? The intention was to do this

Code: Select all

 STM R4!, {R5-R6} 
A good choice!
Thats correct as long as all the registers contain the correct values. You can also use LDM in a similar way to read the input data.
by jahboater
Sat Apr 22, 2017 5:59 pm
Forum: Other programming languages
Topic: 64 bit multiplication segmentation error
Replies: 24
Views: 2973

Re: 64 bit multiplication segmentation error

Given:

extern void multprime(uint64_t *a, uint64_t *b, uint64_t *r);

r2 will contain the result address (a in r0, b in r1, r in r2)

I personally would return a boolean to indicate overflow or some other error.
by jahboater
Sat Apr 22, 2017 5:46 pm
Forum: Other programming languages
Topic: 64 bit multiplication segmentation error
Replies: 24
Views: 2973

Re: 64 bit multiplication segmentation error

Why do you think r4 contains a valid address?
by jahboater
Sat Apr 22, 2017 1:18 pm
Forum: C/C++
Topic: Writing clean code isn't hard!
Replies: 138
Views: 13975

Re: Writing clean code isn't hard!

e.g., for the line putenv ("WIRINGPI GPIOMEM=1"); (got that from one of Gordon's sources) Thats interesting #include <stdlib.h> int putenv(char *string); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): putenv(): _SVID_SOURCE || _XOPEN_SOURCE but read the notes, as you can se...
by jahboater
Sat Apr 22, 2017 1:12 pm
Forum: Other programming languages
Topic: 64 bit multiplication segmentation error
Replies: 24
Views: 2973

Re: 64 bit multiplication segmentation error

Thanks. I tried that earlier but I got the following error; myfunc6.s: Assembler messages: myfunc6.s:12: rdhi, rdlo and rm must all be different That's when I begin to play around with the registers...and I'd been getting segmentation errors since. OK thats interesting. The Assembler (as) on my Pi3...
by jahboater
Sat Apr 22, 2017 8:43 am
Forum: Other programming languages
Topic: 64 bit multiplication segmentation error
Replies: 24
Views: 2973

Re: 64 bit multiplication segmentation error

Well, now you have changed it back to passing an address, you can revert to using ldm again (or ldrd which is faster and intended for the purpose). By the way, the compiler produced code for the multiply is both smaller and faster than the one above (mla is a combined multiply and add - very fast on...
by jahboater
Sat Apr 22, 2017 7:40 am
Forum: Other programming languages
Topic: 64 bit multiplication segmentation error
Replies: 24
Views: 2973

Re: 64 bit multiplication segmentation error

maybe i should have loaded r0 and r1 as LDM r0,{r3-r4} LDM r1,{r5-r6} You shouldn't be loading r0 and r1 at all. The caller will do that for you. C is "call by value", meaning the actual values of the arguments will be passed to the function, not the address of them. "a" will be placed in r0/r1 and...
by jahboater
Sat Apr 22, 2017 7:24 am
Forum: Other programming languages
Topic: 64 bit multiplication segmentation error
Replies: 24
Views: 2973

Re: 64 bit multiplication segmentation error

Why are you using ldm for input a and b ?? How are you expecting to return the result to the C program ? Before proceeding you should research exactly how arguments are passed and how values are returned from such a function. Hint: if you don't want to learn about pointers and call by reference, mak...
by jahboater
Fri Apr 21, 2017 4:07 pm
Forum: C/C++
Topic: C code compiles, but will not run
Replies: 35
Views: 3513

Re: C code compiles, but will not run

This is what i got : http://imgur.com/a/1qhgQ am i doing something wrong? I am really confused, because on the internet i did not saw this kind of problem. To mention, i am using a RaspberryPi3 Model B :D with rasbian and a 16gb sd card Remove the < > they are from BNF, but the shell will use them ...
by jahboater
Thu Apr 20, 2017 8:51 am
Forum: General discussion
Topic: 5 terabytes for the Pi?
Replies: 4
Views: 1762

Re: 5 terabytes for the Pi?

peterlite wrote:What is your experience of speedups like replacing the built in Ethernet with a Gigabit adapter?
I get around:-

321 Mbits/sec Pi3 GiGe USB3 adapter.
95 Mbits/sec Pi3 built in Ethernet.
17 Mbits/sec Pi Zero W Wifi

(using iperf).
by jahboater
Thu Apr 20, 2017 8:38 am
Forum: General discussion
Topic: So Many Languages, so little Time
Replies: 28
Views: 4669

Re: So Many Languages, so little Time

C/Python for multicore, arrays, AI.ML,CV......? You need extra stuff, numpy etc Free Pascal has native support for multicore, arrays... and compiles faster :P I don't think you know C at all. C can of course do almost anything you would ever want (even arrays!!!!!!) Thats why much of the system (Ra...
by jahboater
Tue Apr 18, 2017 7:59 am
Forum: Beginners
Topic: Timed Functions/Clock Data
Replies: 4
Views: 480

Re: Timed Functions/Clock Data

You can use localtime() in C to get broken down time (separate fields for hours, mins etc etc - see "man localtime" ). In Python I use datetime.now() for the same thing. If the Pi has reliable Internet access the time will be extremely accurate, self correcting, and of course self adjusting for summ...
by jahboater
Tue Apr 18, 2017 7:38 am
Forum: General discussion
Topic: Perf/temp differences between Pi2B V1.1/V1.2 and Pi3B V1.2
Replies: 30
Views: 5026

Re: Perf/temp differences between Pi2B V1.1/V1.2 and Pi3B V1

The new Pi2 V1.2 has the same armv8 SoC as the Pi3. The default clock speeds differ. the Pi2 is 900Mhz, the Pi3 is 1.2GHz (hence it is faster and hotter). It is easy to alter the clock speed of any Pi. If you ran them at the same speed, the performance should be much the same.
by jahboater
Mon Apr 17, 2017 7:04 pm
Forum: Raspberry Pi OS
Topic: Jessie lite, ssh gone
Replies: 4
Views: 1996

Re: Jessie lite, ssh gone

Did you look at the release notes ?

Just create a file called "ssh" in the FAT partition and ssh will be enabled on first boot. (Or if thats difficult for you on Windows, try ssh.txt).

Sorry Dougie, cross posted.
Yes, it works for Raspbian Lite too.
by jahboater
Mon Apr 17, 2017 5:58 pm
Forum: Raspberry Pi OS
Topic: Raspbian Jessie (64bit) for RPi3?
Replies: 145
Views: 140849

Re: Raspbian Jessie (64bit) for RPi3?

So, just to get simple and stupid again, like the KISS principle claims us to be... Do you really believe in 64 bits being the solution in turning light bulbs on and of? Someone in another thread is struggling with 64-bit multiplication in assembler. The 32-bit compiler produces: mymul: mul r3, r0,...
by jahboater
Sun Apr 16, 2017 9:34 pm
Forum: C/C++
Topic: How to retrieve the date and time
Replies: 10
Views: 8765

Re: How to retrieve the date and time

ecor wrote:Are there specific functions for just getting the daynumber, year, hour, sec, etc?
As PeterO said:-

Code: Select all

man 3 localtime
by jahboater
Thu Apr 13, 2017 8:17 pm
Forum: Raspberry Pi OS
Topic: Raspbian Jessie (64bit) for RPi3?
Replies: 145
Views: 140849

Re: Raspbian Jessie (64bit) for RPi3?

Is your Ubuntu flavour Canonical Supported or is it a Community Supported effort like Armbian ?? Its for the Pine 64 and the Odroid C2 (which is the only one I now use). I presume its maintained by hardkernel themselves. Where is a fully working .IMG available from ?? http://odroid.com/dokuwiki/dok...
by jahboater
Thu Apr 13, 2017 7:33 pm
Forum: Raspberry Pi OS
Topic: Raspbian Jessie (64bit) for RPi3?
Replies: 145
Views: 140849

Re: Raspbian Jessie (64bit) for RPi3?

....whereas Aarch64 ARM64 Debian is still work in progress: This page contains details about the port of Debian to the 64-bit ARM platform (arm64), known in some other places as AArch64. This port was released for the first time with Jessie (Debian 8). Also, I am happily running aarch64 Ubuntu, and...
by jahboater
Thu Apr 13, 2017 5:18 pm
Forum: Other programming languages
Topic: In quest of portability?
Replies: 55
Views: 7949

Re: In quest of portability?

If you say not to target those things that represent as small of a percentage of users as the platforms that I include, then there are more platforms that have as small or smaller a percentage of total computer users and the Raspberry Pi is one of them. Raspberry Pi == ARM with some 80,000,000,000 ...
by jahboater
Thu Apr 13, 2017 8:33 am
Forum: C/C++
Topic: How to retrieve the date and time
Replies: 10
Views: 8765

Re: How to retrieve the date and time

And "man 7 time" gives a nice overview.

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