From cca75bd8b53b82d80299b03b368355b158832c9a Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Tue, 2 Nov 2021 10:26:23 +0100 Subject: i386: Explain why __HAVE_64B_ATOMICS has to be 0 --- sysdeps/x86/atomic-machine.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'sysdeps/x86/atomic-machine.h') diff --git a/sysdeps/x86/atomic-machine.h b/sysdeps/x86/atomic-machine.h index 695222e4fa..2692d94a92 100644 --- a/sysdeps/x86/atomic-machine.h +++ b/sysdeps/x86/atomic-machine.h @@ -60,6 +60,10 @@ typedef uintmax_t uatomic_max_t; # define BR_CONSTRAINT "q" # define IBR_CONSTRAINT "iq" #else +/* Since the Pentium, i386 CPUs have supported 64-bit atomics, but the + i386 psABI supplement provides only 4-byte alignment for uint64_t + inside structs, so it is currently not possible to use 64-bit + atomics on this platform. */ # define __HAVE_64B_ATOMICS 0 # define SP_REG "esp" # define SEG_REG "gs" -- cgit 1.4.1