Author: jhb
Date: Tue Jul 3 22:03:28 2018
New Revision: 335913
URL: https://svnweb.freebsd.org/changeset/base/335913
Log:
Use 'e' instead of 'i' constraints with 64-bit atomic operations on amd64.
The ADD, AND, OR, and SUB instructions take at most a 32-bit
sign-extended immediate operand. 64-bit constants that do not fit into
that constraint need to be loaded into a register. The 'i' constraint
tells the compiler it can pass any integer constant to the assembler,
whereas the 'e' constrain only permits constants that fit into a 32-bit
sign-extended value. This fixes using
atomic_add/clear/set/subtract_long/64 with constants that do not fit into
a 32-bit sign-extended immediate.
Reported by: several folks
Tested by: Pete Wright <p...@nomadlogic.org>
MFC after: 2 weeks
Modified:
head/sys/amd64/include/atomic.h
Modified: head/sys/amd64/include/atomic.h
==============================================================================
--- head/sys/amd64/include/atomic.h Tue Jul 3 21:29:04 2018
(r335912)
+++ head/sys/amd64/include/atomic.h Tue Jul 3 22:03:28 2018
(r335913)
@@ -446,10 +446,10 @@ ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v);
ATOMIC_ASM(add, int, "addl %1,%0", "ir", v);
ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v);
-ATOMIC_ASM(set, long, "orq %1,%0", "ir", v);
-ATOMIC_ASM(clear, long, "andq %1,%0", "ir", ~v);
-ATOMIC_ASM(add, long, "addq %1,%0", "ir", v);
-ATOMIC_ASM(subtract, long, "subq %1,%0", "ir", v);
+ATOMIC_ASM(set, long, "orq %1,%0", "er", v);
+ATOMIC_ASM(clear, long, "andq %1,%0", "er", ~v);
+ATOMIC_ASM(add, long, "addq %1,%0", "er", v);
+ATOMIC_ASM(subtract, long, "subq %1,%0", "er", v);
#define ATOMIC_LOADSTORE(TYPE) \
ATOMIC_LOAD(TYPE); \
_______________________________________________
svn-src-all@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
