From 8f0f1cfd66eb85be94010a92217862c5d0b4416b Mon Sep 17 00:00:00 2001
From: MerryMage <MerryMage@users.noreply.github.com>
Date: Sun, 21 Jun 2020 16:27:33 +0100
Subject: [PATCH] A32: Implement ASIMD VST{1,2,3,4} (single n-element structure
 from one lane)

---
 src/frontend/A32/decoder/asimd.inc            |  2 +-
 .../impl/asimd_load_store_structures.cpp      | 63 ++++++++++++++++++-
 .../A32/translate/impl/translate_arm.h        |  1 +
 3 files changed, 64 insertions(+), 2 deletions(-)

diff --git a/src/frontend/A32/decoder/asimd.inc b/src/frontend/A32/decoder/asimd.inc
index ab06ed9f..7f38100b 100644
--- a/src/frontend/A32/decoder/asimd.inc
+++ b/src/frontend/A32/decoder/asimd.inc
@@ -127,5 +127,5 @@ INST(arm_UDF,               "UNALLOCATED",              "111101000--0--------11-
 INST(arm_UDF,               "UNALLOCATED",              "111101001-00--------11----------") // v8
 INST(v8_VLD_all_lanes,      "VLD{1-4} (all lanes)",     "111101001D10nnnndddd11nnzzTammmm") // v8
 INST(arm_UDF,               "UNALLOCATED",              "111101001-10--------1110---1----") // v8
-//INST(v8_VST_single,         "VST{1-4} (single)",        "111101001D00nnnnddddzzNNaaaammmm") // v8
+INST(v8_VST_single,         "VST{1-4} (single)",        "111101001D00nnnnddddzzNNaaaammmm") // v8
 INST(v8_VLD_single,         "VLD{1-4} (single)",        "111101001D10nnnnddddzzNNaaaammmm") // v8
diff --git a/src/frontend/A32/translate/impl/asimd_load_store_structures.cpp b/src/frontend/A32/translate/impl/asimd_load_store_structures.cpp
index cf0ed9d0..80b0847f 100644
--- a/src/frontend/A32/translate/impl/asimd_load_store_structures.cpp
+++ b/src/frontend/A32/translate/impl/asimd_load_store_structures.cpp
@@ -235,6 +235,68 @@ bool ArmTranslatorVisitor::v8_VLD_all_lanes(bool D, Reg n, size_t Vd, size_t nn,
     return true;
 }
 
+bool ArmTranslatorVisitor::v8_VST_single(bool D, Reg n, size_t Vd, size_t sz, size_t nn, size_t index_align, Reg m) {
+    const size_t nelem = nn + 1;
+
+    ASSERT_MSG(sz != 0b11, "Decode Error");
+
+    if (nelem == 1 && Common::Bit(sz, index_align)) {
+        return UndefinedInstruction();
+    }
+
+    const size_t ebytes = 1 << sz;
+    const size_t index = Common::Bits(sz + 1, 3, index_align);
+    const size_t inc = (sz != 0 && Common::Bit(sz, index_align)) ? 2 : 1;
+    const size_t a = Common::Bits(0, sz ? sz - 1 : 0, index_align);
+
+    if (nelem == 1 && inc == 2) {
+        return UndefinedInstruction();
+    }
+    if (nelem == 1 && (a != 0b00 && a != 0b11)) {
+        return UndefinedInstruction();
+    }
+    if (nelem == 2 && Common::Bit<1>(a)) {
+        return UndefinedInstruction();
+    }
+    if (nelem == 3 && a != 0b00) {
+        return UndefinedInstruction();
+    }
+    if (nelem == 4 && a == 0b11) {
+        return UndefinedInstruction();
+    }
+
+    // TODO: alignment
+
+    const ExtReg d = ToExtRegD(Vd, D);
+    const size_t d_last = RegNumber(d) + inc * (nelem - 1);
+    if (n == Reg::R15 || d_last + 1 > 32) {
+        return UnpredictableInstruction();
+    }
+
+    const bool wback = m != Reg::R15;
+    const bool register_index = m != Reg::R15 && m != Reg::R13;
+
+    auto address = ir.GetRegister(n);
+    for (size_t i = 0; i < nelem; i++) {
+        const ExtReg ext_reg = d + i * inc;
+        const auto element = ir.VectorGetElement(ebytes * 8, ir.GetVector(ext_reg), index);
+
+        ir.WriteMemory(ebytes * 8, address, element);
+
+        address = ir.Add(address, ir.Imm32(static_cast<u32>(ebytes)));
+    }
+
+    if (wback) {
+        if (register_index) {
+            ir.SetRegister(n, ir.Add(ir.GetRegister(n), ir.GetRegister(m)));
+        } else {
+            ir.SetRegister(n, ir.Add(ir.GetRegister(n), ir.Imm32(static_cast<u32>(nelem * ebytes))));
+        }
+    }
+
+    return true;
+}
+
 bool ArmTranslatorVisitor::v8_VLD_single(bool D, Reg n, size_t Vd, size_t sz, size_t nn, size_t index_align, Reg m) {
     const size_t nelem = nn + 1;
 
@@ -297,5 +359,4 @@ bool ArmTranslatorVisitor::v8_VLD_single(bool D, Reg n, size_t Vd, size_t sz, si
 
     return true;
 }
-
 } // namespace Dynarmic::A32
diff --git a/src/frontend/A32/translate/impl/translate_arm.h b/src/frontend/A32/translate/impl/translate_arm.h
index 5dfa8738..6b194689 100644
--- a/src/frontend/A32/translate/impl/translate_arm.h
+++ b/src/frontend/A32/translate/impl/translate_arm.h
@@ -545,6 +545,7 @@ struct ArmTranslatorVisitor final {
     bool v8_VST_multiple(bool D, Reg n, size_t Vd, Imm<4> type, size_t sz, size_t align, Reg m);
     bool v8_VLD_multiple(bool D, Reg n, size_t Vd, Imm<4> type, size_t sz, size_t align, Reg m);
     bool v8_VLD_all_lanes(bool D, Reg n, size_t Vd, size_t nn, size_t sz, bool T, bool a, Reg m);
+    bool v8_VST_single(bool D, Reg n, size_t Vd, size_t sz, size_t nn, size_t index_align, Reg m);
     bool v8_VLD_single(bool D, Reg n, size_t Vd, size_t sz, size_t nn, size_t index_align, Reg m);
 };