Date: Tue, 3 Jul 2018 22:03:29 +0000 (UTC) From: John Baldwin <jhb@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r335913 - head/sys/amd64/include Message-ID: <201807032203.w63M3T47033074@repo.freebsd.org>
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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 <pete@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); \
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