Fixes buggy FPU tests for MIPS hardware.

runtime/vm/constants_mips.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_CONSTANTS_MIPS_H_
 #define VM_CONSTANTS_MIPS_H_
 
 #include "platform/assert.h"
 
 namespace dart {
@@ skipping 117 matching lines @@
   kNumberOfFRegisters = 32,
   kNoFRegister = -1,
 };
 
 // The double precision floating point registers are concatenated pairs of the
 // single precision registers, e.g. D0 is F1:F0, D1 is F3:F2, etc.. We only
 // tell the architecture generic code about the double precision registers, then
 // convert to the single precision registers when needed in the mips-specific
 // code.
 enum DRegister {
-  D0  =  0,
-  D1  =  1,
-  D2  =  2,
-  D3  =  3,
-  D4  =  4,
-  D5  =  5,
-  D6  =  6,
-  D7  =  7,
-  D8  =  8,
-  D9  =  9,
-  D10 = 10,
-  D11 = 11,
-  D12 = 12,
-  D13 = 13,
-  D14 = 14,
-  D15 = 15,
-  D16 = 16,
+  D0  =  0,  // Function return value 1.
+  D1  =  1,  // Function return value 2.
+  D2  =  2,  // Not preserved.
+  D3  =  3,  // Not preserved.
+  D4  =  4,  // Not preserved.
+  D5  =  5,  // Not preserved.
+  D6  =  6,  // Argument 1.
+  D7  =  7,  // Argument 2.
+  D8  =  8,  // Not preserved.
+  D9  =  9,  // Not preserved.
+  D10 = 10,  // Preserved.
+  D11 = 11,  // Preserved.
+  D12 = 12,  // Preserved.
+  D13 = 13,  // Preserved.
+  D14 = 14,  // Preserved.
+  D15 = 15,  // Preserved.
   kNumberOfDRegisters = 16,
   kNoDRegister = -1,
 };
 
 // Architecture independent aliases.
 typedef DRegister FpuRegister;
 const FpuRegister FpuTMP = D0;
 const int kNumberOfFpuRegisters = kNumberOfDRegisters;
 const FpuRegister kNoFpuRegister = kNoDRegister;
 
@@ skipping 428 matching lines @@
 #endif  // defined(DEBUG)
 
  private:
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(Instr);
 };
 
 }  // namespace dart
 
 #endif  // VM_CONSTANTS_MIPS_H_