From 48c7f8630c29e896702132fddd731d12e1c64af3 Mon Sep 17 00:00:00 2001
From: Lioncash <mathew1800@gmail.com>
Date: Fri, 20 Apr 2018 15:33:14 -0400
Subject: [PATCH] A64: Implement ADDHN{2} and SUBHN{2}

---
 src/frontend/A64/decoder/a64.inc              |  4 +-
 .../A64/translate/impl/simd_three_same.cpp    | 43 +++++++++++++++++++
 2 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/src/frontend/A64/decoder/a64.inc b/src/frontend/A64/decoder/a64.inc
index 3ae84873..73655bd0 100644
--- a/src/frontend/A64/decoder/a64.inc
+++ b/src/frontend/A64/decoder/a64.inc
@@ -679,9 +679,9 @@ INST(SADDL,                  "SADDL, SADDL2",                             "0Q001
 INST(SADDW,                  "SADDW, SADDW2",                             "0Q001110zz1mmmmm000100nnnnnddddd")
 INST(SSUBL,                  "SSUBL, SSUBL2",                             "0Q001110zz1mmmmm001000nnnnnddddd")
 INST(SSUBW,                  "SSUBW, SSUBW2",                             "0Q001110zz1mmmmm001100nnnnnddddd")
-//INST(ADDHN,                  "ADDHN, ADDHN2",                             "0Q001110zz1mmmmm010000nnnnnddddd")
+INST(ADDHN,                  "ADDHN, ADDHN2",                             "0Q001110zz1mmmmm010000nnnnnddddd")
 //INST(SABAL,                  "SABAL, SABAL2",                             "0Q001110zz1mmmmm010100nnnnnddddd")
-//INST(SUBHN,                  "SUBHN, SUBHN2",                             "0Q001110zz1mmmmm011000nnnnnddddd")
+INST(SUBHN,                  "SUBHN, SUBHN2",                             "0Q001110zz1mmmmm011000nnnnnddddd")
 //INST(SABDL,                  "SABDL, SABDL2",                             "0Q001110zz1mmmmm011100nnnnnddddd")
 //INST(SMLAL_vec,              "SMLAL, SMLAL2 (vector)",                    "0Q001110zz1mmmmm100000nnnnnddddd")
 //INST(SMLSL_vec,              "SMLSL, SMLSL2 (vector)",                    "0Q001110zz1mmmmm101000nnnnnddddd")
diff --git a/src/frontend/A64/translate/impl/simd_three_same.cpp b/src/frontend/A64/translate/impl/simd_three_same.cpp
index 71b6130e..1ca87cdd 100644
--- a/src/frontend/A64/translate/impl/simd_three_same.cpp
+++ b/src/frontend/A64/translate/impl/simd_three_same.cpp
@@ -7,6 +7,31 @@
 #include "frontend/A64/translate/impl/impl.h"
 
 namespace Dynarmic::A64 {
+namespace {
+enum class HighNarrowingOp {
+    Add,
+    Subtract,
+};
+
+static void HighNarrowingOperation(TranslatorVisitor& v, bool Q, Imm<2> size, Vec Vm, Vec Vn, Vec Vd,
+                                   HighNarrowingOp op) {
+    const size_t part = Q;
+    const size_t esize = 8 << size.ZeroExtend();
+
+    const IR::U128 operand1 = v.ir.GetQ(Vn);
+    const IR::U128 operand2 = v.ir.GetQ(Vm);
+    const IR::U128 wide = [&] {
+        if (op == HighNarrowingOp::Add) {
+            return v.ir.VectorAdd(2 * esize, operand1, operand2);
+        }
+        return v.ir.VectorSub(2 * esize, operand1, operand2);
+    }();
+    const IR::U128 result = v.ir.VectorNarrow(2 * esize,
+                                              v.ir.VectorLogicalShiftRight(2 * esize, wide, static_cast<u8>(esize)));
+
+    v.Vpart(64, Vd, part, result);
+}
+} // Anonymous namespace
 
 bool TranslatorVisitor::CMGT_reg_2(bool Q, Imm<2> size, Vec Vm, Vec Vn, Vec Vd) {
     if (size == 0b11 && !Q) return ReservedValue();
@@ -109,6 +134,24 @@ bool TranslatorVisitor::MUL_vec(bool Q, Imm<2> size, Vec Vm, Vec Vn, Vec Vd) {
     return true;
 }
 
+bool TranslatorVisitor::ADDHN(bool Q, Imm<2> size, Vec Vm, Vec Vn, Vec Vd) {
+    if (size == 0b11) {
+        return ReservedValue();
+    }
+
+    HighNarrowingOperation(*this, Q, size, Vm, Vn, Vd, HighNarrowingOp::Add);
+    return true;
+}
+
+bool TranslatorVisitor::SUBHN(bool Q, Imm<2> size, Vec Vm, Vec Vn, Vec Vd) {
+    if (size == 0b11) {
+        return ReservedValue();
+    }
+
+    HighNarrowingOperation(*this, Q, size, Vm, Vn, Vd, HighNarrowingOp::Subtract);
+    return true;
+}
+
 bool TranslatorVisitor::ADDP_vec(bool Q, Imm<2> size, Vec Vm, Vec Vn, Vec Vd) {
     if (size == 0b11 && !Q) return ReservedValue();
     const size_t esize = 8 << size.ZeroExtend<size_t>();