Implement Thumb Instructions: BLX (imm), BL (imm)

src/frontend/decoder/thumb32.h

@@ -0,0 +1,82 @@
+/* This file is part of the dynarmic project.
+ * Copyright (c) 2016 MerryMage
+ * This software may be used and distributed according to the terms of the GNU
+ * General Public License version 2 or any later version.
+ */
+
+#pragma once
+
+#include <array>
+#include <functional>
+#include <vector>
+
+#include <boost/optional.hpp>
+
+#include "common/common_types.h"
+#include "frontend/decoder/decoder_detail.h"
+
+namespace Dynarmic {
+namespace Arm {
+
+template <typename Visitor>
+struct Thumb32Matcher {
+    using CallRetT = typename mp::MemFnInfo<decltype(&Visitor::thumb32_UDF), &Visitor::thumb32_UDF>::return_type;
+
+    Thumb32Matcher(const char* const name, u32 mask, u32 expect, std::function<CallRetT(Visitor&, u32)> fn)
+            : name(name), mask(mask), expect(expect), fn(fn) {}
+
+    /// Gets the name of this type of instruction.
+    const char* GetName() const {
+        return name;
+    }
+
+    /**
+     * Tests to see if the instruction is this type of instruction.
+     * @param instruction The instruction to test
+     * @returns true if the instruction is
+     */
+    bool Matches(u32 instruction) const {
+        return (instruction & mask) == expect;
+    }
+
+    /**
+     * Calls the corresponding instruction handler on visitor for this type of instruction.
+     * @param v The visitor to use
+     * @param instruction The instruction to decode.
+     */
+    CallRetT call(Visitor& v, u32 instruction) const {
+        assert(Matches(instruction));
+        return fn(v, instruction);
+    }
+
+private:
+    const char* name;
+    u32 mask, expect;
+    std::function<CallRetT(Visitor&, u32)> fn;
+};
+
+template<typename V>
+boost::optional<const Thumb32Matcher<V>&> DecodeThumb32(u32 instruction) {
+    const static std::vector<Thumb32Matcher<V>> table = {
+
+#define INST(fn, name, bitstring) detail::detail<Thumb32Matcher, u32, 32>::GetMatcher<decltype(fn), fn>(name, bitstring)
+
+        // Branch instructions
+        INST(&V::thumb32_BL_imm,         "BL (imm)",                 "11110vvvvvvvvvvv11111vvvvvvvvvvv"), // v4T
+        INST(&V::thumb32_BLX_imm,        "BLX (imm)",                "11110vvvvvvvvvvv11101vvvvvvvvvvv"), // v5T
+
+        // Misc instructions
+        INST(&V::thumb32_UDF,            "UDF",                      "111101111111----1010------------"), // v6T2
+
+#undef INST
+
+    };
+
+    const auto matches_instruction = [instruction](const auto& matcher){ return matcher.Matches(instruction); };
+
+    auto iter = std::find_if(table.begin(), table.end(), matches_instruction);
+    return iter != table.end() ? boost::make_optional<const Thumb32Matcher<V>&>(*iter) : boost::none;
+}
+
+} // namespace Arm
+} // namespace Dynarmic