diff -r 51e15701116e -r 1562a22c4474 src/arch/alpha/isa/decoder.isa
--- a/src/arch/alpha/isa/decoder.isa	Sat Mar 10 19:55:48 2012 +0000
+++ b/src/arch/alpha/isa/decoder.isa	Sat Mar 10 19:55:51 2012 +0000
@@ -805,14 +805,14 @@
             0x4400: wmb({{ }}, IsWriteBarrier, MemWriteOp);
         }
 
-        0xe000: decode FullSystem {
+        0xe000: decode FullSystemInt {
             0: FailUnimpl::rc_se();
             default: BasicOperate::rc({{
                 Ra = IntrFlag;
                 IntrFlag = 0;
             }}, IsNonSpeculative, IsUnverifiable);
         }
-        0xf000: decode FullSystem {
+        0xf000: decode FullSystemInt {
             0: FailUnimpl::rs_se();
             default: BasicOperate::rs({{
                 Ra = IntrFlag;
@@ -821,7 +821,7 @@
         }
     }
 
-    0x00: decode FullSystem {
+    0x00: decode FullSystemInt {
         0: decode PALFUNC {
             format EmulatedCallPal {
                 0x00: halt ({{
diff -r 51e15701116e -r 1562a22c4474 src/arch/mips/isa/decoder.isa
--- a/src/arch/mips/isa/decoder.isa	Sat Mar 10 19:55:48 2012 +0000
+++ b/src/arch/mips/isa/decoder.isa	Sat Mar 10 19:55:51 2012 +0000
@@ -163,7 +163,7 @@
                 format BasicOp {
                     0x2: movz({{ Rd = (Rt == 0) ? Rs : Rd; }});
                     0x3: movn({{ Rd = (Rt != 0) ? Rs : Rd; }});
-                    0x4: decode FullSystem {
+                    0x4: decode FullSystemInt {
                         0: syscall_se({{ xc->syscall(R2); }},
                                 IsSerializeAfter, IsNonSpeculative);
                         default: syscall({{ fault = new SystemCallFault(); }});
@@ -2431,7 +2431,7 @@
                     }
                 }
                 0x3: decode OP default FailUnimpl::rdhwr() {
-                    0x0: decode FullSystem {
+                    0x0: decode FullSystemInt {
                         0: decode RD {
                             29: BasicOp::rdhwr_se({{ Rt = TpValue; }});
                         }
diff -r 51e15701116e -r 1562a22c4474 src/arch/x86/isa/decoder/one_byte_opcodes.isa
--- a/src/arch/x86/isa/decoder/one_byte_opcodes.isa	Sat Mar 10 19:55:48 2012 +0000
+++ b/src/arch/x86/isa/decoder/one_byte_opcodes.isa	Sat Mar 10 19:55:51 2012 +0000
@@ -394,7 +394,7 @@
                     default: Inst::RET_FAR();
                 }
                 0x4: int3();
-                0x5: decode FullSystem default int_Ib() {
+                0x5: decode FullSystemInt default int_Ib() {
                     0: decode IMMEDIATE {
                         // Really only the LSB matters, but the predecoder
                         // will sign extend it, and there's no easy way to
diff -r 51e15701116e -r 1562a22c4474 src/arch/x86/isa/decoder/two_byte_opcodes.isa
--- a/src/arch/x86/isa/decoder/two_byte_opcodes.isa	Sat Mar 10 19:55:48 2012 +0000
+++ b/src/arch/x86/isa/decoder/two_byte_opcodes.isa	Sat Mar 10 19:55:51 2012 +0000
@@ -216,7 +216,7 @@
                         default: Inst::UD2();
                     }
                 }
-                0x05: decode FullSystem {
+                0x05: decode FullSystemInt {
                     0: SyscallInst::syscall('xc->syscall(Rax)',
                             IsSyscall, IsNonSpeculative, IsSerializeAfter);
                     default: decode MODE_MODE {
@@ -398,7 +398,7 @@
                 0x1: Inst::RDTSC();
                 0x2: Inst::RDMSR();
                 0x3: rdpmc();
-                0x4: decode FullSystem {
+                0x4: decode FullSystemInt {
                     0: SyscallInst::sysenter('xc->syscall(Rax)',
                             IsSyscall, IsNonSpeculative, IsSerializeAfter);
                     default: sysenter();
diff -r 51e15701116e -r 1562a22c4474 src/cpu/base.hh
--- a/src/cpu/base.hh	Sat Mar 10 19:55:48 2012 +0000
+++ b/src/cpu/base.hh	Sat Mar 10 19:55:51 2012 +0000
@@ -58,7 +58,7 @@
 #include "sim/full_system.hh"
 #include "sim/insttracer.hh"
 
-class BaseCPUParams;
+struct BaseCPUParams;
 class BranchPred;
 class CheckerCPU;
 class ThreadContext;
diff -r 51e15701116e -r 1562a22c4474 src/sim/full_system.hh
--- a/src/sim/full_system.hh	Sat Mar 10 19:55:48 2012 +0000
+++ b/src/sim/full_system.hh	Sat Mar 10 19:55:51 2012 +0000
@@ -31,6 +31,18 @@
 #ifndef __SIM_FULL_SYSTEM_HH__
 #define __SIM_FULL_SYSTEM_HH__
 
+/**
+ * The FullSystem variable can be used to determine the current mode
+ * of simulation.
+ */
 extern bool FullSystem;
 
+/**
+ * In addition to the boolean flag we make use of an unsigned int
+ * since the CPU instruction decoder makes use of the variable in
+ * switch statements. A value of 0 signifies syscall emulation, and
+ * any other value full system.
+ */
+extern unsigned int FullSystemInt;
+
 #endif // __SIM_FULL_SYSTEM_HH__
diff -r 51e15701116e -r 1562a22c4474 src/sim/root.cc
--- a/src/sim/root.cc	Sat Mar 10 19:55:48 2012 +0000
+++ b/src/sim/root.cc	Sat Mar 10 19:55:51 2012 +0000
@@ -125,6 +125,7 @@
 }
 
 bool FullSystem;
+unsigned int FullSystemInt;
 
 Root *
 RootParams::create()
@@ -136,6 +137,7 @@
     created = true;
 
     FullSystem = full_system;
+    FullSystemInt = full_system ? 1 : 0;
 
     return new Root(this);
 }