make the ARM clock shift configurable. nothing fancy there, just paving the way for DSi support later.

src/ARM.h

@@ -38,6 +38,12 @@ public:
 
     void Reset();
 
+    void SetClockShift(u32 shift)
+    {
+        ClockShift = shift;
+        ClockDiffMask = (1<<shift) - 1;
+    }
+
     void DoSavestate(Savestate* file);
 
     void JumpTo(u32 addr, bool restorecpsr = false);
@@ -227,6 +233,11 @@ public:
 
     u32 Num;
 
+    // shift relative to system clock
+    // 0=33MHz 1=66MHz 2=133MHz
+    u32 ClockShift;
+    u32 ClockDiffMask;
+
     // waitstates:
     // 0=code16 1=code32 2=data16 3=data32
     // TODO eventually: nonsequential waitstates