Purpose of memory alignment

Question

Admittedly I don\'t get it. Say you have a memory with a memory word of length of 1 byte. Why can\'t you access a 4 byte long variable in a single memory access on an unalig

Answer 1

On PowerPC you can load an integer from an odd address with no problems.

Sparc and I86 and (I think) Itatnium raise hardware exceptions when you try this.

One 32 bit load vs four 8 bit loads isnt going to make a lot of difference on most modern processors. Whether the data is already in cache or not will have a far greater effect.