11-12-2022, 02:02 AM
(11-12-2022, 01:43 AM)megamarc Wrote: Hi!
Reading byte by byte is not a problem, as you can read a byte on any boundary. Just personal experience, some years ago I wrote a FAT filesystem driver for an embedded device that was a bit of a headache. The FAT table has lots of word values (i.e. two-byte fields) that are unaligned. Trying to read those words on that device (a Renesas H8S) on unaligned boundaries caused CPU faults. I had to read all those unaligned words as two individual bytes, and then reconstruct the word value merging the two bytes. A simple word read should be much more elegant.
On Intel CPUs you won't have any problem. But if your format ever goes to ARM (cell phones, etc) developers writing a PAL64 handler will face these kind of problems:
https://developer.arm.com/documentation/ka003038/latest
So for portability and ease of implementation, I recommend you to place data fields on aligned boundaries relative to their natural data size
Oh alright, thanks for your advice! I'll try to rework the format and do some tests on an ARM device or emulator.