// Fetch count bits starting at bit start from value

#define GB(value, start, count) (((value) >> (start)) & ((1 << (count)) - 1))

// Set count bits in value starting at bit start to data

#define SB(value, start, count, data) ((value) = ((value) & ~(((1 << (count)) - 1) << (start))) | ((data) << (start)))