Specifications

Errata
Intel
®
Core
™
2 Duo Processor
Specification Update 37
[r/e]BP instructions without having an invalid stack during interrupt handling.
However, an enabled debug breakpoint or single step trap may be taken after
MOV SS/POP SS if this instruction is followed by an instruction that signals a
floating point exception rather than a MOV [r/e]SP, [r/e]BP instruction. This
results in a debug exception being signaled on an unexpected instruction
boundary since the MOV SS/POP SS and the following instruction should be
executed atomically.
Implication: This can result in incorrect signaling of a debug exception and possibly a
mismatched Stack Segment and Stack Pointer. If MOV SS/POP SS is not
followed by a MOV [r/e]SP, [r/e]BP, there may be a mismatched Stack
Segment and Stack Pointer on any exception. Intel has not observed this
erratum with any commercially available software, or system.
Workaround: As recommended in the IA32 Intel® Architecture Software Developer’s
Manual, the use of MOV SS/POP SS in conjunction with MOV [r/e]SP, [r/e]BP
will avoid the failure since the MOV [r/e]SP, [r/e]BP will not generate a
floating point exception. Developers of debug tools should be aware of the
potential incorrect debug event signaling created by this erratum.
Status: For the steppings affected, see the Summary Tables of Changes.
AW53. LER MSRs May be Incorrectly Updated
Problem: The LER (Last Exception Record) MSRs, MSR_LER_FROM_LIP (1DDH) and
MSR_LER_TO_LIP (1DEH) may contain incorrect values after any of the
following:
 Either STPCLK#, NMI (NonMaskable Interrupt) or external interrupts
 CMP or TEST instructions with an uncacheable memory operand
followed by a conditional jump
 STI/POP SS/MOV SS instructions followed by CMP or TEST instructions
and then by a conditional jump
Implication: When the conditions for this erratum occur, the value of the LER MSRs may
be incorrectly updated.
Workaround: None identified.
Status: For the steppings affected, see the Summary Tables of Changes.
AW54. IA32_MC1_STATUS MSR Bit[60] Does Not Reflect Machine Check
Error Reporting Enable Correctly
Problem: IA32_MC1_STATUS MSR (405H) bit[60] (EN- Error Enabled) is supposed to
indicate whether the enable bit in the IA32_MC1_CTL MSR (404H) was set at
the time of the last update to the IA32_MC1_STATUS MSR. Due to this
erratum, IA32_MC1_STATUS MSR bit[60] instead reports the current value of
the IA32_MC1_CTL MSR enable bit.