... > We also need this style of checking for the delta logic in __atoi_add(). have > randomly tried different clang and gcc versions, seems all of them work > correctly, but the compiling speed is not that good if we want to support the > worst cases like "((0x900000 + 0x0f0000) + 5)", the shorter one > "((0x900000+0x0f0000)+5)" is used by ARM+OABI (not supported by nolibc > currently), therefore, we can strip some tailing branches but it is either not > that fast, of course, the other architectures/variants can use faster > __atoi_add() versions with less branches and without hex detection, comparison > and calculating. If there are only a few prefix offsets then the code can be optimised to explicitly detect them - rather than decoding arbitrary hex values. After all it only needs to decode the values that actually appear. The code also needs a compile-time assert that the result is constant (__buitin_constant_p() will do the check. But you can't use _Static_assert() to report the error because that requires an 'integer constant expression'. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
