Tag Archives: featurenotbug

version control of tools – part 2

Posted by KarlP on 31 May, 2015 None comments

Oh look! again! Remember kids, it’s not just compilers that you should keep around, but libc/binutils, and all libraries you’re ever going to use.

Today it’s avr-libc, and this gem:

In file included from ../../common/FreqCounter.h:17:0,
                 from ../../common/FreqCounter.c:35:
/usr/avr/include/util/delay.h: In function '__vector_21':
/usr/avr/include/util/delay.h:246:2: error: __builtin_avr_delay_cycles expects a compile time integer constant
  __builtin_avr_delay_cycles(__ticks_dc);
  ^

Apparently it was always actually a requirement in the notes, but everyone did it anyway. Now, you need to write a wrapper function like this sort of shit:

void do_what_I_say_delay_us(int us) {
     while (us-- > 0) {
         _delay_us(1);
     }
}

Hooray, isn’t that better for everyone! See http://nongnu.org/avr-libc/user-manual/group__util__delay.html for more information, if you can read carefully enough :)

version control of tools

Posted by KarlP on 30 May, 2015 None comments

Ahh, it’s always the right thing to do, but normally it’s so heavy to check in things like GCC/Binutils versions into every project. It’s the sort of thing you do if you’re a big serious company, working on big serious things, with big serious support. Besides, I’m not relying on anything weird or esoteric right?

Wrong.


../../common/pjrc/usb_debug_only.c:96:45: error: variable 'device_descriptor' must be const in order to be put into read-only section by means of '__attribute__((progmem))'
static uint8_t PROGMEM device_descriptor[] = {

Thanks for nothing avr-gcc updates. I understand what you’re getting at, but still, this used to compile, and put things in PROGMEM. Now it fails the compile. GCC bug in question is https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44643, or at least, that’s where it came from. A nice case of, “everybody’s using this code, but it was never actually meant to work, so let’s make it fail for them all, like it was meant to anyway.”

Compilers are awesome.