On Mon, Mar 03, 2008 at 11:22:19AM +0100, Guido Draheim wrote: [...] > There is no redesign required - this problem can only occur on non-x86 > little-endian platforms. > > You did not tell about that detail but I can guess it from the result. In > fetch.h there is > #define zzip_file_header_get_crc32(__p) ZZIP_GET32((__p)->z_crc32) > and that ZZIP_GET32 can be defined in a way that it would fetch each byte > seperately. This is already done on a lot of platforms - the definition > is dependent on ZZIP_WORDS_BIGENDIAN and covers acrchitectures like SPARC > which have aligned word access as well. However, SPARC is big-endian as > have been all the other test platforms in the lab. So, what's your target > platform currently? If I am guessing right then would need to redefine > the #ifdefs and configure detections in such a way that it would enable a > bytewise access macro on a litte-endian platform right there in fetch.h
Sparc is big-endian, but that's not what causes a problem here (even though it would be nice to check that endianness is detected correctly for sparc). Let's say that the macro which will get used is this one: # define ZZIP_GET32(__p) bswap_32(*(uint32_t*)(__p)) This will only work on sparc if the address __p is word-aligned (divisible by 4). Compiler is likely to generate a single load-word instruction for that, and if __p is not word-aligned, then the process will get a SIGBUS. Normally, it happens automatically, i.e. if you define an int (of size 4) field inside a struct, then compiler will take care of allocating memory for it in such a way that it is word-aligned. However, since the structures in format.h are defined mostly using arrays of zzip_byte_t, there is no way the compiler can guess which of them should be aligned, so it places them arbitrarily. Thus, attempt to cast the value to uint32_t fails. Best regards, -- Jurij Smakov [EMAIL PROTECTED] Key: http://www.wooyd.org/pgpkey/ KeyID: C99E03CC -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
