On Dec 19, 2007 12:35 PM, Weddington, Eric <[EMAIL PROTECTED]> wrote: > > The General Purpose I/O Registers (GPIOR0 through GIPOR3) are directly > > bit-accessible. It would be a very handy feature to be able to place a > > static bool (or any variable, I suppose) in the GPIO registers. > > Hi Shaun, > > Could you be more specific? Anyone can use bitwise operators now to > achieve this. Do you have something different in mind? > > Eric
Bit flags in GPIO registers can be accomplished right now using accessor macros, such as #define my_flag (GPIOR0 & 0x80) #define set_my_flag(f) ((f) ? (GPIOR0 |= 0x80) : (GPIOR0 &= ~0x80)) This method works fine, so the functionality does already exist. The need to use a set_my_flag macro is not ideal though. I'd like to be able to change only the declaration of static bool my_flag; without having to change all the code that accesses it. In particular, changing all the instances of my_flag = true; to set_my_flag(true). So, my wishlist item is to be able to use an attribute on a static bool to locate it in the GPIO section, similar to PROGMEM, such as #define IOMEM __attribute__((__iomem__)) static bool IOMEM my_flag; I suspect this feature would probably require a fair bit of GCC hacking for a relatively minor syntactic improvement, but I'd appreciate it! Cheers, Shaun _______________________________________________ AVR-libc-dev mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/avr-libc-dev
