emit_x64_floating_point: Simplify indexers

src/backend_x64/emit_x64_vector_floating_point.cpp

@@ -5,12 +5,14 @@
  */
 
 #include <array>
+#include <tuple>
 #include <type_traits>
 #include <utility>
 
 #include "backend_x64/abi.h"
 #include "backend_x64/block_of_code.h"
 #include "backend_x64/emit_x64.h"
+#include "common/assert.h"
 #include "common/bit_util.h"
 #include "common/fp/fpcr.h"
 #include "common/fp/info.h"
@@ -26,7 +28,7 @@ namespace Dynarmic::BackendX64 {
 using namespace Xbyak::util;
 namespace mp = Common::mp;
 
-template <size_t fsize, typename T>
+template<size_t fsize, typename T>
 static T ChooseOnFsize(T f32, T f64) {
     static_assert(fsize == 32 || fsize == 64, "fsize must be either 32 or 64");
 
@@ -39,12 +41,12 @@ static T ChooseOnFsize(T f32, T f64) {
 
 #define FCODE(NAME) (code.*ChooseOnFsize<fsize>(&Xbyak::CodeGenerator::NAME##s, &Xbyak::CodeGenerator::NAME##d))
 
-template<typename T, auto IndexFunction, size_t... argi>
+template<typename T, template<typename> class Indexer, size_t... argi>
 static auto GetRuntimeNaNFunction(std::index_sequence<argi...>) {
     auto result = [](std::array<VectorArray<T>, sizeof...(argi) + 1>& values) {
         VectorArray<T>& result = values[0];
         for (size_t elementi = 0; elementi < result.size(); ++elementi) {
-            const auto current_values = IndexFunction(elementi, values[argi + 1]...);
+            const auto current_values = Indexer<T>{}(elementi, values[argi + 1]...);
             if (auto r = FP::ProcessNaNs(std::get<argi>(current_values)...)) {
                 result[elementi] = *r;
             } else if (FP::IsNaN(result[elementi])) {
@@ -55,7 +57,7 @@ static auto GetRuntimeNaNFunction(std::index_sequence<argi...>) {
     return static_cast<mp::equivalent_function_type_t<decltype(result)>*>(result);
 }
 
-template <size_t fsize, size_t nargs, auto IndexFunction>
+template<size_t fsize, size_t nargs, template<typename> class Indexer>
 static void HandleNaNs(BlockOfCode& code, EmitContext& ctx, std::array<Xbyak::Xmm, nargs + 1> xmms, const Xbyak::Xmm& nan_mask) {
     static_assert(fsize == 32 || fsize == 64, "fsize must be either 32 or 64");
 
@@ -90,7 +92,7 @@ static void HandleNaNs(BlockOfCode& code, EmitContext& ctx, std::array<Xbyak::Xm
     code.lea(code.ABI_PARAM1, ptr[rsp + ABI_SHADOW_SPACE + 0 * 16]);
 
     using T = mp::unsigned_integer_of_size<fsize>;
-    code.CallFunction(GetRuntimeNaNFunction<T, IndexFunction>(std::make_index_sequence<nargs>{}));
+    code.CallFunction(GetRuntimeNaNFunction<T, Indexer>(std::make_index_sequence<nargs>{}));
 
     code.movaps(result, xword[rsp + ABI_SHADOW_SPACE + 0 * 16]);
     code.add(rsp, stack_space + ABI_SHADOW_SPACE);
@@ -100,41 +102,59 @@ static void HandleNaNs(BlockOfCode& code, EmitContext& ctx, std::array<Xbyak::Xm
     code.SwitchToNearCode();
 }
 
-static std::tuple<u32, u32> DefaultIndexFunction32(size_t i, const VectorArray<u32>& a, const VectorArray<u32>& b) {
+template<typename T>
+struct DefaultIndexer {
+    std::tuple<T, T> operator()(size_t i, const VectorArray<T>& a, const VectorArray<T>& b) {
         return std::make_tuple(a[i], b[i]);
-}
-
-static std::tuple<u64, u64> DefaultIndexFunction64(size_t i, const VectorArray<u64>& a, const VectorArray<u64>& b) {
-    return std::make_tuple(a[i], b[i]);
-}
-
-static std::tuple<u32, u32> PairedIndexFunction32(size_t i, const VectorArray<u32>& a, const VectorArray<u32>& b) {
-    if (i < 2) {
-        return std::make_tuple(a[2 * i], a[2 * i + 1]);
     }
-    return std::make_tuple(b[2 * (i - 2)], b[2 * (i - 2) + 1]);
-}
 
-static std::tuple<u64, u64> PairedIndexFunction64(size_t i, const VectorArray<u64>& a, const VectorArray<u64>& b) {
+    std::tuple<T, T, T> operator()(size_t i, const VectorArray<T>& a, const VectorArray<T>& b, const VectorArray<T>& c) {
-    return i == 0 ? std::make_tuple(a[0], a[1]) : std::make_tuple(b[0], b[1]);
+        return std::make_tuple(a[i], b[i], c[i]);
-}
+    }
+};
 
-static std::tuple<u32, u32> PairedLowerIndexFunction32(size_t i, const VectorArray<u32>& a, const VectorArray<u32>& b) {
+template<typename T>
+struct PairedIndexer {
+    std::tuple<T, T> operator()(size_t i, const VectorArray<T>& a, const VectorArray<T>& b) {
+        constexpr size_t halfway = std::tuple_size_v<VectorArray<T>> / 2;
+        const size_t which_array = i / halfway;
+        i %= halfway;
+        switch (which_array) {
+        case 0:
+            return std::make_tuple(a[2 * i], a[2 * i + 1]);
+        case 1:
+            return std::make_tuple(b[2 * i], b[2 * i + 1]);
+        }
+        UNREACHABLE();
+        return {};
+    }
+};
+
+template<typename T>
+struct PairedLowerIndexer {
+    std::tuple<T, T> operator()(size_t i, const VectorArray<T>& a, const VectorArray<T>& b) {
+        constexpr size_t array_size = std::tuple_size_v<VectorArray<T>>;
+        if constexpr (array_size == 4) {
             switch (i) {
             case 0:
                 return std::make_tuple(a[0], a[1]);
             case 1:
                 return std::make_tuple(b[0], b[1]);
             default:
-        return std::make_tuple(u32(0), u32(0));
+                return std::make_tuple(0, 0);
             }
-}
+        } else if constexpr (array_size == 2) {
+            if (i == 0) {
+                return std::make_tuple(a[0], b[0]);
+            }
+            return std::make_tuple(0, 0);
+        }
+        UNREACHABLE();
+        return {};
+    }
+};
 
-static std::tuple<u64, u64> PairedLowerIndexFunction64(size_t i, const VectorArray<u64>& a, const VectorArray<u64>& b) {
+template<size_t fsize, template<typename> class Indexer, typename Function>
-    return i == 0 ? std::make_tuple(a[0], b[0]) : std::make_tuple(u64(0), u64(0));
-}
-
-template <size_t fsize, auto IndexFunction, typename Function>
 static void EmitThreeOpVectorOperation(BlockOfCode& code, EmitContext& ctx, IR::Inst* inst, Function fn) {
     static_assert(fsize == 32 || fsize == 64, "fsize must be either 32 or 64");
 
@@ -182,7 +202,7 @@ static void EmitThreeOpVectorOperation(BlockOfCode& code, EmitContext& ctx, IR::
     }
     FCODE(cmpunordp)(nan_mask, result);
 
-    HandleNaNs<fsize, 2, IndexFunction>(code, ctx, {result, xmm_a, xmm_b}, nan_mask);
+    HandleNaNs<fsize, 2, Indexer>(code, ctx, {result, xmm_a, xmm_b}, nan_mask);
 
     ctx.reg_alloc.DefineValue(inst, result);
 }
@@ -212,7 +232,7 @@ inline void EmitOneArgumentFallback(BlockOfCode& code, EmitContext& ctx, IR::Ins
     ctx.reg_alloc.DefineValue(inst, xmm0);
 }
 
-template <typename Lambda>
+template<typename Lambda>
 inline void EmitTwoArgumentFallback(BlockOfCode& code, EmitContext& ctx, IR::Inst* inst, Lambda lambda) {
     const auto fn = static_cast<mp::equivalent_function_type_t<Lambda>*>(lambda);
 
@@ -290,19 +310,19 @@ void EmitX64::EmitFPVectorAbs64(EmitContext& ctx, IR::Inst* inst) {
 }
 
 void EmitX64::EmitFPVectorAdd32(EmitContext& ctx, IR::Inst* inst) {
-    EmitThreeOpVectorOperation<32, DefaultIndexFunction32>(code, ctx, inst, &Xbyak::CodeGenerator::addps);
+    EmitThreeOpVectorOperation<32, DefaultIndexer>(code, ctx, inst, &Xbyak::CodeGenerator::addps);
 }
 
 void EmitX64::EmitFPVectorAdd64(EmitContext& ctx, IR::Inst* inst) {
-    EmitThreeOpVectorOperation<64, DefaultIndexFunction64>(code, ctx, inst, &Xbyak::CodeGenerator::addpd);
+    EmitThreeOpVectorOperation<64, DefaultIndexer>(code, ctx, inst, &Xbyak::CodeGenerator::addpd);
 }
 
 void EmitX64::EmitFPVectorDiv32(EmitContext& ctx, IR::Inst* inst) {
-    EmitThreeOpVectorOperation<32, DefaultIndexFunction32>(code, ctx, inst, &Xbyak::CodeGenerator::divps);
+    EmitThreeOpVectorOperation<32, DefaultIndexer>(code, ctx, inst, &Xbyak::CodeGenerator::divps);
 }
 
 void EmitX64::EmitFPVectorDiv64(EmitContext& ctx, IR::Inst* inst) {
-    EmitThreeOpVectorOperation<64, DefaultIndexFunction64>(code, ctx, inst, &Xbyak::CodeGenerator::divpd);
+    EmitThreeOpVectorOperation<64, DefaultIndexer>(code, ctx, inst, &Xbyak::CodeGenerator::divpd);
 }
 
 void EmitX64::EmitFPVectorEqual32(EmitContext& ctx, IR::Inst* inst) {
@@ -366,23 +386,23 @@ void EmitX64::EmitFPVectorGreaterEqual64(EmitContext& ctx, IR::Inst* inst) {
 }
 
 void EmitX64::EmitFPVectorMul32(EmitContext& ctx, IR::Inst* inst) {
-    EmitThreeOpVectorOperation<32, DefaultIndexFunction32>(code, ctx, inst, &Xbyak::CodeGenerator::mulps);
+    EmitThreeOpVectorOperation<32, DefaultIndexer>(code, ctx, inst, &Xbyak::CodeGenerator::mulps);
 }
 
 void EmitX64::EmitFPVectorMul64(EmitContext& ctx, IR::Inst* inst) {
-    EmitThreeOpVectorOperation<64, DefaultIndexFunction64>(code, ctx, inst, &Xbyak::CodeGenerator::mulpd);
+    EmitThreeOpVectorOperation<64, DefaultIndexer>(code, ctx, inst, &Xbyak::CodeGenerator::mulpd);
 }
 
 void EmitX64::EmitFPVectorPairedAdd32(EmitContext& ctx, IR::Inst* inst) {
-    EmitThreeOpVectorOperation<32, PairedIndexFunction32>(code, ctx, inst, &Xbyak::CodeGenerator::haddps);
+    EmitThreeOpVectorOperation<32, PairedIndexer>(code, ctx, inst, &Xbyak::CodeGenerator::haddps);
 }
 
 void EmitX64::EmitFPVectorPairedAdd64(EmitContext& ctx, IR::Inst* inst) {
-    EmitThreeOpVectorOperation<64, PairedIndexFunction64>(code, ctx, inst, &Xbyak::CodeGenerator::haddpd);
+    EmitThreeOpVectorOperation<64, PairedIndexer>(code, ctx, inst, &Xbyak::CodeGenerator::haddpd);
 }
 
 void EmitX64::EmitFPVectorPairedAddLower32(EmitContext& ctx, IR::Inst* inst) {
-    EmitThreeOpVectorOperation<32, PairedLowerIndexFunction32>(code, ctx, inst, [&](Xbyak::Xmm result, Xbyak::Xmm xmm_b) {
+    EmitThreeOpVectorOperation<32, PairedLowerIndexer>(code, ctx, inst, [&](Xbyak::Xmm result, Xbyak::Xmm xmm_b) {
         const Xbyak::Xmm zero = ctx.reg_alloc.ScratchXmm();
         code.xorps(zero, zero);
         code.punpcklqdq(result, xmm_b);
@@ -391,7 +411,7 @@ void EmitX64::EmitFPVectorPairedAddLower32(EmitContext& ctx, IR::Inst* inst) {
 }
 
 void EmitX64::EmitFPVectorPairedAddLower64(EmitContext& ctx, IR::Inst* inst) {
-    EmitThreeOpVectorOperation<64, PairedLowerIndexFunction64>(code, ctx, inst, [&](Xbyak::Xmm result, Xbyak::Xmm xmm_b) {
+    EmitThreeOpVectorOperation<64, PairedLowerIndexer>(code, ctx, inst, [&](Xbyak::Xmm result, Xbyak::Xmm xmm_b) {
         const Xbyak::Xmm zero = ctx.reg_alloc.ScratchXmm();
         code.xorps(zero, zero);
         code.punpcklqdq(result, xmm_b); 
@@ -484,11 +504,11 @@ void EmitX64::EmitFPVectorS64ToDouble(EmitContext& ctx, IR::Inst* inst) {
 }
 
 void EmitX64::EmitFPVectorSub32(EmitContext& ctx, IR::Inst* inst) {
-    EmitThreeOpVectorOperation<32, DefaultIndexFunction32>(code, ctx, inst, &Xbyak::CodeGenerator::subps);
+    EmitThreeOpVectorOperation<32, DefaultIndexer>(code, ctx, inst, &Xbyak::CodeGenerator::subps);
 }
 
 void EmitX64::EmitFPVectorSub64(EmitContext& ctx, IR::Inst* inst) {
-    EmitThreeOpVectorOperation<64, DefaultIndexFunction64>(code, ctx, inst, &Xbyak::CodeGenerator::subpd);
+    EmitThreeOpVectorOperation<64, DefaultIndexer>(code, ctx, inst, &Xbyak::CodeGenerator::subpd);
 }
 
 void EmitX64::EmitFPVectorU32ToSingle(EmitContext& ctx, IR::Inst* inst) {