embedded

Most of the objections I see to using global variables make sense since they refer to issues of multiple threads, thread safety, etc. But in a small, single threaded, non-OS, case, what objections do you have? In my case, I'm writing my embedded system in "C", if it matters. I'm also the only developer on the product. Why would eliminating global variables make my code better? (After reading several responses, I realize I also should have pointed out that this system has no dynamic memory allocation (e.g. malloc). All the memory is statically allocated at compile time.) It wouldn't. The two

I am writing some embedded code in C and need to use the rand() function. Unfortunately, rand() is not supported in the library for the controller. I need a simple implementation that is fast, but more importantly has little space overhead, that produces relatively high-quality random numbers. Does anyone know which algorithm to use or sample code? EDIT: It's for image processing, so "relatively high quality" means decent cycle length and good uniform properties. Check out this collection of random number generators from George Marsaglia. He's a leading expert in random number generation, so I

I'm trying to access physical memory directly for an embedded Linux project, but I'm not sure how I can best designate memory for my use. If I boot my device regularly, and access /dev/mem, I can easily read and write to just about anywhere I want. However, in this, I'm accessing memory that can easily be allocated to any process; which I don't want to do My code for /dev/mem is (all error checking, etc. removed): mem_fd = open("/dev/mem", O_RDWR)); mem_p = malloc(SIZE + (PAGE_SIZE - 1)); if ((unsigned long) mem_p % PAGE_SIZE) { mem_p += PAGE_SIZE - ((unsigned long) mem_p % PAGE_SIZE); } mem_p

I have always been an embedded software engineer, but usually at Layer 3 or 2 of the OSI stack. I am not really a hardware guy. I have generally always done telecoms products, usually hand/cell-phones, which generally means something like an ARM 7 processor. Now I find myself in a more generic embedded world, in a small start-up, where I might move to "not so powerful" processors (there's the subjective bit) - I cannot predict which. I have read quite a bit about debate about using STL in C++ in embedded systems and there is no clear cut answer. There are some small worries about portability,

Question I have two compilers on my hardware C++ and C89 I'm thinking about using C++ with classes but without polymorphism (to avoid vtables). The main reasons I’d like to use C++ are: I prefer to use “inline” functions instead of macro definitions. I’d like to use namespaces as I prefixes clutter the code. I see C++ a bit type safer mainly because of templates, and verbose casting. I really like overloaded functions and constructors (used for automatic casting). Do you see any reason to stick with C89 when developing for very limited hardware (4kb of RAM)? Conclusion Thank you for your