diff options
Diffstat (limited to 'src/cpu/o3/O3CPU.py')
| -rw-r--r-- | src/cpu/o3/O3CPU.py | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/src/cpu/o3/O3CPU.py b/src/cpu/o3/O3CPU.py index 4b94f3581..044ee9d59 100644 --- a/src/cpu/o3/O3CPU.py +++ b/src/cpu/o3/O3CPU.py @@ -112,7 +112,18 @@ class DerivO3CPU(BaseCPU): numPhysIntRegs = Param.Unsigned(256, "Number of physical integer registers") numPhysFloatRegs = Param.Unsigned(256, "Number of physical floating point " "registers") - numPhysCCRegs = Param.Unsigned(0, "Number of physical cc registers") + # most ISAs don't use condition-code regs, so default is 0 + _defaultNumPhysCCRegs = 0 + if buildEnv['TARGET_ISA'] == 'x86': + # For x86, each CC reg is used to hold only a subset of the + # flags, so we need 4-5 times the number of CC regs as + # physical integer regs to be sure we don't run out. In + # typical real machines, CC regs are not explicitly renamed + # (it's a side effect of int reg renaming), so they should + # never be the bottleneck here. + _defaultNumPhysCCRegs = Self.numPhysIntRegs * 5 + numPhysCCRegs = Param.Unsigned(_defaultNumPhysCCRegs, + "Number of physical cc registers") numIQEntries = Param.Unsigned(64, "Number of instruction queue entries") numROBEntries = Param.Unsigned(192, "Number of reorder buffer entries") |