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| author | Andreas Sandberg <andreas@sandberg.pp.se> | 2013-06-18 16:36:08 +0200 |
|---|---|---|
| committer | Andreas Sandberg <andreas@sandberg.pp.se> | 2013-06-18 16:36:08 +0200 |
| commit | d06064c38613662dfbf68a701052278b4018de8c (patch) | |
| tree | cc7870da633caf1c52abbd624c37754fe5a99b52 /src/arch/x86/faults.cc | |
| parent | a8e8c4f433fb3cce354950ba72136b84abb78015 (diff) | |
| download | gem5-d06064c38613662dfbf68a701052278b4018de8c.tar.xz | |
x86: Add support for maintaining the x87 tag word
The current implementation of the x87 never updates the x87 tag
word. This is currently not a big issue since the simulated x87 never
checks for stack overflows, however this becomes an issue when
switching between a virtualized CPU and a simulated CPU. This
changeset adds support, which is enabled by default, for updating the
tag register to every floating point microop that updates the stack
top using the spm mechanism.
The new tag words is generated by the helper function
X86ISA::genX87Tags(). This function is currently limited to flagging a
stack position as valid or invalid and does not try to distinguish
between the valid, zero, and special states.
Diffstat (limited to 'src/arch/x86/faults.cc')
| -rw-r--r-- | src/arch/x86/faults.cc | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/src/arch/x86/faults.cc b/src/arch/x86/faults.cc index 995326562..aa859052e 100644 --- a/src/arch/x86/faults.cc +++ b/src/arch/x86/faults.cc @@ -270,6 +270,9 @@ namespace X86ISA tc->setMiscReg(MISCREG_MXCSR, 0x1f80); + // Flag all elements on the x87 stack as empty. + tc->setMiscReg(MISCREG_FTW, 0xFFFF); + // Update the handy M5 Reg. tc->setMiscReg(MISCREG_M5_REG, 0); MicroPC entry = X86ISAInst::RomLabels::extern_label_initIntHalt; |