Clarify result returned by remainder intrinsics.

runtime/vm/intrinsifier_mips.cc

 // 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.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_MIPS.
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/intrinsifier.h"
 
 #include "vm/assembler.h"
@@ skipping 346 matching lines @@
 
 
 // Optimizations:
 // - result is 0 if:
 //   - left is 0
 //   - left equals right
 // - result is left if
 //   - left > 0 && left < right
 // T1: Tagged left (dividend).
 // T0: Tagged right (divisor).
-// V0: Untagged result.
+// Returns:
+//   V0: Untagged fallthrough result (remainder to be adjusted), or
+//   V0: Tagged return result (remainder).

[zra, 2015/02/06 22:27:34]

V1 is available here if it would help to be consistent with the other
architectures.

[regis, 2015/02/06 22:42:40]

It does not have to be. X64 uses RAX in both cases as well.

 static void EmitRemainderOperation(Assembler* assembler) {
   Label return_zero, modulo;
   const Register left = T1;
   const Register right = T0;
   const Register result = V0;
 
   __ beq(left, ZR, &return_zero);
   __ beq(left, right, &return_zero);
 
   __ bltz(left, &modulo);
@@ skipping 1649 matching lines @@
   Isolate* isolate = Isolate::Current();
   __ LoadImmediate(V0, reinterpret_cast<uword>(isolate));
   // Set return value.
   __ Ret();
   __ delay_slot()->lw(V0, Address(V0, Isolate::current_tag_offset()));
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS