Initial Alloy implementation.

This is a regression in functionality and performance, but a much better
foundation for the future of the project (I think). It can run basic
apps under an SSA interpreter but doesn't support some of the features
required to do real 360 apps yet.

src/alloy/backend/ivm/ivm_function.cc

@@ -0,0 +1,66 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2013 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#include <alloy/backend/ivm/ivm_function.h>
+
+#include <alloy/backend/tracing.h>
+#include <alloy/runtime/thread_state.h>
+
+using namespace alloy;
+using namespace alloy::backend;
+using namespace alloy::backend::ivm;
+using namespace alloy::runtime;
+
+
+IVMFunction::IVMFunction(FunctionInfo* symbol_info) :
+    register_count_(0), intcode_count_(0), intcodes_(0),
+    GuestFunction(symbol_info) {
+}
+
+IVMFunction::~IVMFunction() {
+  xe_free(intcodes_);
+}
+
+void IVMFunction::Setup(TranslationContext& ctx) {
+  register_count_ = ctx.register_count;
+  intcode_count_ = ctx.intcode_count;
+  intcodes_ = (IntCode*)ctx.intcode_arena->CloneContents();
+}
+
+int IVMFunction::CallImpl(ThreadState* thread_state) {
+  // Setup register file on stack.
+  size_t register_file_size = register_count_ * sizeof(Register);
+  Register* register_file = (Register*)alloca(register_file_size);
+
+  IntCodeState ics;
+  ics.rf = register_file;
+  ics.context = (uint8_t*)thread_state->raw_context();
+  ics.membase = thread_state->memory()->membase();
+  ics.did_carry = 0;
+  ics.thread_state = thread_state;
+  ics.return_address = 0xBEBEBEBE;
+
+  // TODO(benvanik): DID_CARRY -- need HIR to set a OPCODE_FLAG_SET_CARRY
+  //                 or something so the fns can set an ics flag.
+
+  uint32_t ia = 0;
+  while (true) {
+    const IntCode* i = &intcodes_[ia];
+    uint32_t new_ia = i->intcode_fn(ics, i);
+    if (new_ia == IA_NEXT) {
+      ia++;
+    } else if (new_ia == IA_RETURN) {
+      break;
+    } else {
+      ia = new_ia;
+    }
+  }
+
+  return 0;
+}