#9346: AtomicPrimOps tests failing on 32-bit x86 -------------------------------------+------------------------------------- Reporter: niklasl | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.9 Resolution: | Keywords: Differential Revisions: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: Difficulty: Unknown | Blocking: Blocked By: | Related Tickets: | -------------------------------------+------------------------------------- Comment (by tibbe): The `mov` instruction doesn't support a lock prefix. From: "Intel® 64 and IA-32 ArchitecturesSoftware Developer’s Manual":
The LOCK prefix can be prepended only to the following instructions and only to those forms of the instructions where the destination operand is a memory operand: ADD, ADC, AND, BTC, BTR, BTS, CMPXCHG, CMPXCH8B, DEC, INC, NEG, NOT, OR, SBB, SUB, XOR, XADD, and XCHG. If the LOCK prefix is used with one of these instructions and the source operand is a memory operand, an undefined opcode exception (#UD) may be generated. An undefined opcode exception will also be generated if the LOCK prefix is used with any instruction not in the above list. The XCHG instruction always asserts the LOCK# signal regardless of the presence or absence of the LOCK prefix
However, I cannot see a place where we're adding one in the x86 codegen: https://github.com/ghc/ghc/blob/master/compiler/nativeGen/X86/CodeGen.hs -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9346#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler