diff --git a/src/cpu/simple_thread.hh b/src/cpu/simple_thread.hh
index c018e3e491..2b79c97081 100644
--- a/src/cpu/simple_thread.hh
+++ b/src/cpu/simple_thread.hh
@@ -241,25 +241,25 @@ class SimpleThread : public ThreadState
 
     FloatReg readFloatReg(int reg_idx, int width)
     {
-        int flatIndex = TheISA::flattenIntIndex(getTC(), reg_idx);
+        int flatIndex = TheISA::flattenFloatIndex(getTC(), reg_idx);
         return regs.readFloatReg(flatIndex, width);
     }
 
     FloatReg readFloatReg(int reg_idx)
     {
-        int flatIndex = TheISA::flattenIntIndex(getTC(), reg_idx);
+        int flatIndex = TheISA::flattenFloatIndex(getTC(), reg_idx);
         return regs.readFloatReg(flatIndex);
     }
 
     FloatRegBits readFloatRegBits(int reg_idx, int width)
     {
-        int flatIndex = TheISA::flattenIntIndex(getTC(), reg_idx);
+        int flatIndex = TheISA::flattenFloatIndex(getTC(), reg_idx);
         return regs.readFloatRegBits(flatIndex, width);
     }
 
     FloatRegBits readFloatRegBits(int reg_idx)
     {
-        int flatIndex = TheISA::flattenIntIndex(getTC(), reg_idx);
+        int flatIndex = TheISA::flattenFloatIndex(getTC(), reg_idx);
         return regs.readFloatRegBits(flatIndex);
     }
 
@@ -271,25 +271,25 @@ class SimpleThread : public ThreadState
 
     void setFloatReg(int reg_idx, FloatReg val, int width)
     {
-        int flatIndex = TheISA::flattenIntIndex(getTC(), reg_idx);
+        int flatIndex = TheISA::flattenFloatIndex(getTC(), reg_idx);
         regs.setFloatReg(flatIndex, val, width);
     }
 
     void setFloatReg(int reg_idx, FloatReg val)
     {
-        int flatIndex = TheISA::flattenIntIndex(getTC(), reg_idx);
+        int flatIndex = TheISA::flattenFloatIndex(getTC(), reg_idx);
         regs.setFloatReg(flatIndex, val);
     }
 
     void setFloatRegBits(int reg_idx, FloatRegBits val, int width)
     {
-        int flatIndex = TheISA::flattenIntIndex(getTC(), reg_idx);
+        int flatIndex = TheISA::flattenFloatIndex(getTC(), reg_idx);
         regs.setFloatRegBits(flatIndex, val, width);
     }
 
     void setFloatRegBits(int reg_idx, FloatRegBits val)
     {
-        int flatIndex = TheISA::flattenIntIndex(getTC(), reg_idx);
+        int flatIndex = TheISA::flattenFloatIndex(getTC(), reg_idx);
         regs.setFloatRegBits(flatIndex, val);
     }