I am trying to write an inline asm statement that atomically adds a number to a
memory variable. Here's what I came up with:
#define atomic_add(mem,val) asm volatile ("lock; add%z0 %1, %0": "+m" (mem):
"ir" (val))
This appears to work fine on x86, but in 64-bit mode %z returns "ll" instead of
"q" for 64-bit values like size_t, and thus the assembler complains like this:
t.c:53: Error: no such instruction: `addll $3,x.5802(%rip)'
If I understand %z correctly, this is exactly what it is meant for... right?
Please make it return "q" in this case.
--
Summary: inline asm %z on amd64 says "ll" instead of "q"
Product: gcc
Version: 4.4.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: inline-asm
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: felix-gcc at fefe dot de
GCC build triplet: x86_64-unknown-linux-gnu
GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: x86_64-unknown-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39590
