For a very resource constrained target such as 4KB of RAM, I’d test the waters with some samples before committing a lot of effort that can’t be easily ported back into a pure ANSI C implementation. The Embedded C++ working group did propose a standard subset of the language and a standard subset of the … Read more
Working for about 4-5 years with software/firmware development and environment testing of miniaturized satellites*, I would like to share my experience here. *(miniaturized satellites are a lot more prone to single event upsets than bigger satellites due to its relatively small, limited sizes for its electronic components) To be very concise and direct: there is … Read more
This problem is known as the subset sum problem, which is a special case of the Knapsack problem. Wikipedia is a good starting point for some algorithms.
Remember that assignment is done right to left, and that they are normal expressions. So from the compilers perspective the line sample1 = sample2 = 0; is the same as sample1 = (sample2 = 0); which is the same as sample2 = 0; sample1 = sample2; That is, sample2 is assigned zero, then sample1 is … Read more
@floppes recommends to: Read RCC_CSR as soon as possible after startup, before initializing any other peripheral. It is safe to initialize your system clocks first (which is done in SystemInit() if you use ST’s libraries). Now, to determine the exact reset cause, here’s a full function to help you. Note that all reset flags can … Read more
In the context of Linux, the boot loader is responsible for some predefined tasks. As this question is arm tagged, I think that ARM booting might be a useful resource. Specifically, the boot loader was/is responsible for setting up an ATAG list that describing the amount of RAM, a kernel command line, and other parameters. … Read more
You can absolutely make a c program from assembler. The problem is it may not look like what you are thinking, or maybe it will. My PIC is rusty but using another assembler, say you had add r1,r2 In C lets say that becomes r1 = r1 + r2; Possibly more readable. You lose any … Read more
I have some preferences (and pet peeves) from writing software to control media and display devices using RS232. Depending on your hardware, some of these may not apply: I think it’s a good idea to make your protocol more friendly for automation. If you need an interactive interface (command line or other), build it separately … Read more
Two issues here: Whether and when keeping certain fields together is an optimization. How to do actually do it. The reason that it might help, is that memory is loaded into the CPU cache in chunks called “cache lines”. This takes time, and generally speaking the more cache lines loaded for your object, the longer … Read more
Here is a function you might find useful: utf8_to_latin9(). It converts to ISO-8859-15 (including EURO, which ISO-8859-1 does not have), but also works correctly for the UTF-8->ISO-8859-1 conversion part of a ISO-8859-1->UTF-8->ISO-8859-1 round-trip. The function ignores invalid code points similar to //IGNORE flag for iconv, but does not recompose decomposed UTF-8 sequences; that is, it … Read more