> In C, there is no type "byte" (unless you typedef oder #define it). > "byte" is usually (but not necessarily) meant as "unsigned char". In C spec, there is a concept of "byte". The union return by sizeof() is byte. Char must fit in a byte. But char does not necessary have the same bits as byte. Char can have more. C99: 3.6, 3.7.1 Because char can always fit in byte, sizeof(char) == 1. > IIRC C specifies that sizeof() returns values measured in chars, but I don't believe it specifies any mapping between the size of chars and the underlying addressing units --- it should be > possible to use 16-bit chars, for example, on an 8-bit byte system. Using 32-bit ints, sizeof(int) would then return 2; but you wouldn't be able to access individual bytes from C. sizeof() return value measure in _byte_. C99: 6.5.3.4 On Fri, Jun 27, 2008 at 8:45 AM, David Given <dg@xxxxxxxxxxx> wrote: > Bernd Petrovitsch wrote: > [...] >> >> That's the bug. there is no difference between "byte" and "char". Tell >> it that a char has 32 bits too *if* it's the case. No, there is a different between "byte" and "char". See above. > > Having checked the standard it turns out that we've been talking at cross > purposes as I've been using the wrong terminology --- it actually defines > (unhelpfully) that byte and char are the same size. Sorry for the confusion. > > What I was referring to when I previously said (erroneously) 'byte' was 'an > address delta of 1', as understood by the assembler. Let's just call this a > 'unit' for clarity. This is not necessarily the same size as a char. In C's term, that is call a "byte" :-) > I'm proposing adding a bits_in_unit (or something) setting and then going > through and tracking down these places and changing them to use it. That way > it should still work fine on exotic architectures like mine. You are right that point out a bug (assumption) of sparse which byte is 8 bits. Using bits_in_byte is instead of 8 is better there. Using bits_in_char assumes char has same bits as byte. That is my read of the C spec. Thanks Chris -- To unsubscribe from this list: send the line "unsubscribe linux-sparse" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
