1 files changed, 59 insertions, 0 deletions
diff --git a/externals/dynarmic/src/dynarmic/common/fp/op/FPRecipExponent.cpp b/externals/dynarmic/src/dynarmic/common/fp/op/FPRecipExponent.cpp
new file mode 100644
index 0000000000..171b94e96e
--- /dev/null
+++ b/externals/dynarmic/src/dynarmic/common/fp/op/FPRecipExponent.cpp
@@ -0,0 +1,59 @@
+/* This file is part of the dynarmic project.
+ * Copyright (c) 2018 MerryMage
+ * SPDX-License-Identifier: 0BSD
+ */
+
+#include "dynarmic/common/fp/op/FPRecipExponent.h"
+
+#include <mcl/bit/bit_field.hpp>
+#include <mcl/stdint.hpp>
+
+#include "dynarmic/common/fp/fpcr.h"
+#include "dynarmic/common/fp/fpsr.h"
+#include "dynarmic/common/fp/info.h"
+#include "dynarmic/common/fp/process_nan.h"
+#include "dynarmic/common/fp/unpacked.h"
+
+namespace Dynarmic::FP {
+namespace {
+template<typename FPT>
+FPT DetermineExponentValue(size_t value) {
+    if constexpr (sizeof(FPT) == sizeof(u32)) {
+        return static_cast<FPT>(mcl::bit::get_bits<23, 30>(value));
+    } else if constexpr (sizeof(FPT) == sizeof(u64)) {
+        return static_cast<FPT>(mcl::bit::get_bits<52, 62>(value));
+    } else {
+        return static_cast<FPT>(mcl::bit::get_bits<10, 14>(value));
+    }
+}
+}  // Anonymous namespace
+
+template<typename FPT>
+FPT FPRecipExponent(FPT op, FPCR fpcr, FPSR& fpsr) {
+    const auto [type, sign, value] = FPUnpack<FPT>(op, fpcr, fpsr);
+    (void)value;
+
+    if (type == FPType::SNaN || type == FPType::QNaN) {
+        return FPProcessNaN(type, op, fpcr, fpsr);
+    }
+
+    const FPT sign_bits = FPInfo<FPT>::Zero(sign);
+    const FPT exponent = DetermineExponentValue<FPT>(op);
+
+    // Zero and denormals
+    if (exponent == 0) {
+        const FPT max_exponent = mcl::bit::ones<FPT>(FPInfo<FPT>::exponent_width) - 1;
+        return FPT(sign_bits | (max_exponent << FPInfo<FPT>::explicit_mantissa_width));
+    }
+
+    // Infinities and normals
+    const FPT negated_exponent = FPT(~exponent);
+    const FPT adjusted_exponent = FPT(negated_exponent << FPInfo<FPT>::explicit_mantissa_width) & FPInfo<FPT>::exponent_mask;
+    return FPT(sign_bits | adjusted_exponent);
+}
+
+template u16 FPRecipExponent<u16>(u16 op, FPCR fpcr, FPSR& fpsr);
+template u32 FPRecipExponent<u32>(u32 op, FPCR fpcr, FPSR& fpsr);
+template u64 FPRecipExponent<u64>(u64 op, FPCR fpcr, FPSR& fpsr);
+
+}  // namespace Dynarmic::FP