svn commit: r338727 - stable/11/sys/amd64/include

[John Baldwin]

Author: jhb
Date: Mon Sep 17 18:45:16 2018
New Revision: 338727
URL: https://svnweb.freebsd.org/changeset/base/338727

Log:
  MFC 335913:
  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.

Modified:
  stable/11/sys/amd64/include/atomic.h
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/sys/amd64/include/atomic.h
==============================================================================
--- stable/11/sys/amd64/include/atomic.h	Mon Sep 17 18:36:29 2018	(r338726)
+++ stable/11/sys/amd64/include/atomic.h	Mon Sep 17 18:45:16 2018	(r338727)
@@ -444,10 +444,10 @@ 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);					\