DBC: Implement OneByteStringFromCharCode and StringToCharCode.

runtime/vm/simulator_dbc.cc

 // Copyright (c) 2016, 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 <setjmp.h>  // NOLINT
 #include <stdlib.h>
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_DBC)
 
@@ skipping 10 matching lines @@
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
 #include "vm/disassembler.h"
 #include "vm/lockers.h"
 #include "vm/native_arguments.h"
 #include "vm/native_entry.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/os_thread.h"
 #include "vm/stack_frame.h"
+#include "vm/symbols.h"
 
 namespace dart {
 
 DEFINE_FLAG(uint64_t, trace_sim_after, ULLONG_MAX,
             "Trace simulator execution after instruction count reached.");
 DEFINE_FLAG(uint64_t, stop_sim_at, ULLONG_MAX,
             "Instruction address or instruction count to stop simulator at.");
 
 // SimulatorSetjmpBuffer are linked together, and the last created one
 // is referenced by the Simulator. When an exception is thrown, the exception
@@ skipping 1477 matching lines @@
     SP[-0] = 0;  // argc_tag is not smi tagged!
     SP[-1] = null_value;
     Exit(thread, FP, SP + 1, pc);
     NativeArguments args(thread, argc_tag, incoming_args, SP - 1);
     INVOKE_NATIVE_WRAPPER(native_target, args);
     SP -= 1;
     DISPATCH();
   }
 
   {
+    BYTECODE(OneByteStringFromCharCode, A_X);
+    const intptr_t char_code = Smi::Value(RAW_CAST(Smi, FP[rD]));
+    ASSERT(char_code >= 0);
+    ASSERT(char_code <= 255);
+    RawString** strings = Symbols::PredefinedAddress();
+    const intptr_t index = char_code + Symbols::kNullCharCodeSymbolOffset;
+    FP[rA] = strings[index];
+    DISPATCH();
+  }
+
+  {
+    BYTECODE(StringToCharCode, A_X);
+    RawOneByteString* str = RAW_CAST(OneByteString, FP[rD]);
+    if (str->ptr()->length_ == Smi::New(1)) {
+      FP[rA] = Smi::New(str->ptr()->data()[0]);
+    } else {
+      FP[rA] = Smi::New(-1);
+    }
+    DISPATCH();
+  }
+
+  {
     BYTECODE(AddTOS, A_B_C);
     SMI_FASTPATH_TOS(intptr_t, SignedAddWithOverflow);
     DISPATCH();
   }
   {
     BYTECODE(SubTOS, A_B_C);
     SMI_FASTPATH_TOS(intptr_t, SignedSubWithOverflow);
     DISPATCH();
   }
   {
@@ skipping 819 matching lines @@
   special_[kExceptionSpecialIndex] = raw_exception;
   special_[kStacktraceSpecialIndex] = raw_stacktrace;
   buf->Longjmp();
   UNREACHABLE();
 }
 
 }  // namespace dart
 
 
 #endif  // defined TARGET_ARCH_DBC