ARM: Improved double to integer truncation....

src/arm/lithium-codegen-arm.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 197 matching lines @@
   void EmitIntegerMathAbs(LUnaryMathOperation* instr);
   void DoMathAbs(LUnaryMathOperation* instr);
   void DoMathFloor(LUnaryMathOperation* instr);
   void DoMathRound(LUnaryMathOperation* instr);
   void DoMathSqrt(LUnaryMathOperation* instr);
   void DoMathPowHalf(LUnaryMathOperation* instr);
   void DoMathLog(LUnaryMathOperation* instr);
   void DoMathCos(LUnaryMathOperation* instr);
   void DoMathSin(LUnaryMathOperation* instr);
 
+  // Helpers for math operations.
+
+  // Helper for EmitECMATruncate.
+  // Tries to truncate using a vcvt instruction.
+  enum TruncationType {
+    kUnsignedTruncation,
+    kSignedTruncation
+  };
+
+  void TryVcvtTruncation(Register result,
+                         DwVfpRegister double_input,
+                         Register saved_fpscr,
+                         Register current_fpscr,
+                         SwVfpRegister single_scratch,
+                         TruncationType type,
+                         Label* success);
+
+  // Performs a truncating conversion of a floating point number as used by
+  // the JS bitwise operations. See ECMA-262 9.5: ToInt32.
+  // Jumps to the 'done' label if the truncation is successful, and falls
+  // through if it was not.
+  void EmitECMATruncate(Register result,
+                        Register scratch1,
+                        Register scratch2,
+                        DwVfpRegister double_input,
+                        DwVfpRegister double_scratch1,
+                        DwVfpRegister double_scratch2,
+                        Label* done);

[Karl Klose, 2011/03/09 10:37:51]

These functions should perhaps be in the macro assembler, because they are not
specific for lithium code generation and the macro assembler already contains FP
conversion and truncation operations.

[Alexandre, 2011/03/15 08:45:39]

Done.

+
   // Support for recording safepoint and position information.
   void RecordSafepoint(LPointerMap* pointers,
                        Safepoint::Kind kind,
                        int arguments,
                        int deoptimization_index);
   void RecordSafepoint(LPointerMap* pointers, int deoptimization_index);
   void RecordSafepoint(int deoptimization_index);
   void RecordSafepointWithRegisters(LPointerMap* pointers,
                                     int arguments,
                                     int deoptimization_index);
@@ skipping 80 matching lines @@
  private:
   LCodeGen* codegen_;
   Label entry_;
   Label exit_;
   Label* external_exit_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_LITHIUM_CODEGEN_ARM_H_