it basics: types and number representation

types (int,long,..) often vary in size and therfore one uses standard types: qtypes_t where q is a qualifier, type is the base type, s is the width in bits and _t is an extension so you know you are using the C99 defined types (e.g., uint8_t)

negative binary number representations:

1. sign bit: one bit is specialized as a sign bit
2. one's complement:
   • "not" operator applied to positive number yields neg. number
   • advantage: subtraction is easy (just add and also add additional carry over bit)
3. two's complement:
   • same as one's comp. but you always add an additional one
   • advantag: subtraction is even easier (just add) and all simple math op. are now easy to manage

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source: bottomupcs.com