On 8/3/20 3:27 AM, David Laight wrote: > From: Mark Rutland >> Sent: 31 July 2020 19:32 > ... >>> It requires PC-relative data references. I have not worked on all architectures. >>> So, I need to study this. But do all ISAs support PC-relative data references? >> Not all do, but pretty much any recent ISA will as it's a practical >> necessity for fast position-independent code. > i386 has neither PC-relative addressing nor moves from %pc. > The cpu architecture knows that the sequence: > call 1f > 1: pop %reg > is used to get the %pc value so is treated specially so that > it doesn't 'trash' the return stack. > > So PIC code isn't too bad, but you have to use the correct > sequence. Is that true only for 32-bit systems only? I thought RIP-relative addressing was introduced in 64-bit mode. Please confirm. Madhavan
