X86: Fix argument register indexing.

Code was assuming that all argument registers followed in order from ArgumentReg0. There is now an ArgumentReg array which is indexed to find the right index. There is a constant, NumArgumentRegs, which can be used to protect against using an invalid ArgumentReg.

--HG--
extra : convert_revision : f448a3ca4d6adc3fc3323562870f70eec05a8a1f

1 files changed, 4 insertions, 2 deletions

diff --git a/src/cpu/simple_thread.hh b/src/cpu/simple_thread.hh
index c20fe3d90..6c6d5f842 100644
--- a/src/cpu/simple_thread.hh
+++ b/src/cpu/simple_thread.hh
@@ -377,15 +377,17 @@ class SimpleThread : public ThreadState
 #if !FULL_SYSTEM
     TheISA::IntReg getSyscallArg(int i)
     {
+        assert(i < TheISA::NumArgumentRegs);
         return regs.readIntReg(TheISA::flattenIntIndex(getTC(),
-                    TheISA::ArgumentReg0 + i));
+                    TheISA::ArgumentReg[i]));
     }
 
     // used to shift args for indirect syscall
     void setSyscallArg(int i, TheISA::IntReg val)
     {
+        assert(i < TheISA::NumArgumentRegs);
         regs.setIntReg(TheISA::flattenIntIndex(getTC(),
-                    TheISA::ArgumentReg0 + i), val);
+                    TheISA::ArgumentReg[i]), val);
     }
 
     void setSyscallReturn(SyscallReturn return_value)