isa: Add parameter to pick different decoder inside ISA

The decoder is responsible for splitting instructions in micro
operations (uops). Given that different micro architectures may split
operations differently, this patch allows to specify which micro
architecture each isa implements, so different cores in the system can
split instructions differently, also decoupling uop splitting
(microArch) from ISA (Arch). This is done making the decodification
calls templates that receive a type 'DecoderFlavour' that maps the
name of the operation to the class that implements it. This way there
is only one selection point (converting the command line enum to the
appropriate DecodeFeatures object). In addition, there is no explicit
code replication: template instantiation hides that, and the compiler
should be able to resolve a number of things at compile-time.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/arch/arm/isa.hh b/src/arch/arm/isa.hh
index a07017c17..ab5c72e6a 100644
--- a/src/arch/arm/isa.hh
+++ b/src/arch/arm/isa.hh
@@ -50,6 +50,7 @@
 #include "arch/arm/types.hh"
 #include "debug/Checkpoint.hh"
 #include "sim/sim_object.hh"
+#include "enums/DecoderFlavour.hh"
 
 struct ArmISAParams;
 struct DummyArmISADeviceParams;
@@ -132,6 +133,9 @@ namespace ArmISA
         // Parent system
         ArmSystem *system;
 
+        // Micro Architecture
+        const Enums::DecoderFlavour _decoderFlavour;
+
         /** Dummy device for to handle non-existing ISA devices */
         DummyISADevice dummyDevice;
 
@@ -429,6 +433,8 @@ namespace ArmISA
 
         void startup(ThreadContext *tc) {}
 
+        Enums::DecoderFlavour decoderFlavour() const { return _decoderFlavour; }
+
         /// Explicitly import the otherwise hidden startup
         using SimObject::startup;