fp: Implement FPMulAdd

src/common/fp/op/FPMulAdd.cpp

@@ -0,0 +1,79 @@
+/* This file is part of the dynarmic project.
+ * Copyright (c) 2018 MerryMage
+ * This software may be used and distributed according to the terms of the GNU
+ * General Public License version 2 or any later version.
+ */
+
+#include "common/common_types.h"
+#include "common/fp/fpcr.h"
+#include "common/fp/fpsr.h"
+#include "common/fp/info.h"
+#include "common/fp/fused.h"
+#include "common/fp/op/FPMulAdd.h"
+#include "common/fp/process_exception.h"
+#include "common/fp/process_nan.h"
+#include "common/fp/unpacked.h"
+
+namespace Dynarmic::FP {
+
+template<typename FPT>
+FPT FPMulAdd(FPT addend, FPT op1, FPT op2, FPCR fpcr, FPSR& fpsr) {
+    const RoundingMode rounding = fpcr.RMode();
+
+    const auto [typeA, signA, valueA] = FPUnpack(addend, fpcr, fpsr);
+    const auto [type1, sign1, value1] = FPUnpack(op1, fpcr, fpsr);
+    const auto [type2, sign2, value2] = FPUnpack(op2, fpcr, fpsr);
+
+    const bool infA = typeA == FPType::Infinity;
+    const bool inf1 = type1 == FPType::Infinity;
+    const bool inf2 = type2 == FPType::Infinity;
+    const bool zeroA = typeA == FPType::Zero;
+    const bool zero1 = type1 == FPType::Zero;
+    const bool zero2 = type2 == FPType::Zero;
+
+    const auto maybe_nan = FPProcessNaNs3<FPT>(typeA, type1, type2, addend, op1, op2, fpcr, fpsr);
+
+    if (typeA == FPType::QNaN && ((inf1 && zero2) || (zero1 && inf2))) {
+        FPProcessException(FPExc::InvalidOp, fpcr, fpsr);
+        return FPInfo<FPT>::DefaultNaN();
+    }
+
+    if (maybe_nan) {
+        return *maybe_nan;
+    }
+
+    // Calculate properties of product (op1 * op2).
+    const bool signP = sign1 != sign2;
+    const bool infP = inf1 || inf2;
+    const bool zeroP = zero1 || zero2;
+
+    // Raise NaN on (inf * inf) of opposite signs or (inf * zero).
+    if ((inf1 && zero2) || (zero1 && inf2) || (infA && infP && signA != signP)) {
+        FPProcessException(FPExc::InvalidOp, fpcr, fpsr);
+        return FPInfo<FPT>::DefaultNaN();
+    }
+
+    // Handle infinities
+    if ((infA && !signA) || (infP && !signP)) {
+        return FPInfo<FPT>::Infinity(false);
+    }
+    if ((infA && signA) || (infP && signP)) {
+        return FPInfo<FPT>::Infinity(true);
+    }
+
+    // Result is exactly zero
+    if (zeroA && zeroP && signA == signP) {
+        return FPInfo<FPT>::Zero(signA);
+    }
+
+    const FPUnpacked result_value = FusedMulAdd(valueA, value1, value2);
+    if (result_value.mantissa == 0) {
+        return FPInfo<FPT>::Zero(rounding == RoundingMode::TowardsMinusInfinity);
+    }
+    return FPRound<FPT>(result_value, fpcr, fpsr);
+}
+
+template u32 FPMulAdd<u32>(u32 addend, u32 op1, u32 op2, FPCR fpcr, FPSR& fpsr);
+template u64 FPMulAdd<u64>(u64 addend, u64 op1, u64 op2, FPCR fpcr, FPSR& fpsr);
+
+} // namespace Dynarmic::FP