From a1b845b6514e135a5810b12c20261ec646216c28 Mon Sep 17 00:00:00 2001
From: ReinUsesLisp <reinuseslisp@airmail.cc>
Date: Mon, 24 Dec 2018 01:23:00 -0300
Subject: shader_decode: Implement VMAD and VSETP

---
 src/video_core/shader/decode/video.cpp | 120 +++++++++++++++++++++++++++++++++
 1 file changed, 120 insertions(+)
 create mode 100644 src/video_core/shader/decode/video.cpp

(limited to 'src/video_core/shader/decode/video.cpp')

diff --git a/src/video_core/shader/decode/video.cpp b/src/video_core/shader/decode/video.cpp
new file mode 100644
index 000000000..9510896e4
--- /dev/null
+++ b/src/video_core/shader/decode/video.cpp
@@ -0,0 +1,120 @@
+// Copyright 2018 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "common/assert.h"
+#include "common/common_types.h"
+#include "video_core/engines/shader_bytecode.h"
+#include "video_core/shader/shader_ir.h"
+
+namespace VideoCommon::Shader {
+
+using Tegra::Shader::Instruction;
+using Tegra::Shader::OpCode;
+using Tegra::Shader::Pred;
+using Tegra::Shader::VideoType;
+using Tegra::Shader::VmadShr;
+
+u32 ShaderIR::DecodeVideo(BasicBlock& bb, u32 pc) {
+    const Instruction instr = {program_code[pc]};
+    const auto opcode = OpCode::Decode(instr);
+
+    const Node op_a =
+        GetVideoOperand(GetRegister(instr.gpr8), instr.video.is_byte_chunk_a, instr.video.signed_a,
+                        instr.video.type_a, instr.video.byte_height_a);
+    const Node op_b = [&]() {
+        if (instr.video.use_register_b) {
+            return GetVideoOperand(GetRegister(instr.gpr20), instr.video.is_byte_chunk_b,
+                                   instr.video.signed_b, instr.video.type_b,
+                                   instr.video.byte_height_b);
+        }
+        if (instr.video.signed_b) {
+            const auto imm = static_cast<s16>(instr.alu.GetImm20_16());
+            return Immediate(static_cast<u32>(imm));
+        } else {
+            return Immediate(instr.alu.GetImm20_16());
+        }
+    }();
+
+    switch (opcode->get().GetId()) {
+    case OpCode::Id::VMAD: {
+        UNIMPLEMENTED_IF_MSG(instr.generates_cc,
+                             "Condition codes generation in VMAD is not implemented");
+
+        const bool result_signed = instr.video.signed_a == 1 || instr.video.signed_b == 1;
+        const Node op_c = GetRegister(instr.gpr39);
+
+        Node value = SignedOperation(OperationCode::IMul, result_signed, NO_PRECISE, op_a, op_b);
+        value = SignedOperation(OperationCode::IAdd, result_signed, NO_PRECISE, value, op_c);
+
+        if (instr.vmad.shr == VmadShr::Shr7 || instr.vmad.shr == VmadShr::Shr15) {
+            const Node shift = Immediate(instr.vmad.shr == VmadShr::Shr7 ? 7 : 15);
+            value =
+                SignedOperation(OperationCode::IArithmeticShiftRight, result_signed, value, shift);
+        }
+
+        SetRegister(bb, instr.gpr0, value);
+
+        break;
+    }
+    case OpCode::Id::VSETP: {
+        // We can't use the constant predicate as destination.
+        ASSERT(instr.vsetp.pred3 != static_cast<u64>(Pred::UnusedIndex));
+
+        const bool sign = instr.video.signed_a == 1 || instr.video.signed_b == 1;
+        const Node first_pred = GetPredicateComparisonInteger(instr.vsetp.cond, sign, op_a, op_b);
+        const Node second_pred = GetPredicate(instr.vsetp.pred39, false);
+
+        const OperationCode combiner = GetPredicateCombiner(instr.vsetp.op);
+
+        // Set the primary predicate to the result of Predicate OP SecondPredicate
+        SetPredicate(bb, instr.vsetp.pred3, Operation(combiner, first_pred, second_pred));
+
+        if (instr.vsetp.pred0 != static_cast<u64>(Pred::UnusedIndex)) {
+            // Set the secondary predicate to the result of !Predicate OP SecondPredicate,
+            // if enabled
+            const Node negate_pred = Operation(OperationCode::LogicalNegate, first_pred);
+            SetPredicate(bb, instr.vsetp.pred0, Operation(combiner, negate_pred, second_pred));
+        }
+        break;
+    }
+    default:
+        UNIMPLEMENTED_MSG("Unhandled video instruction: {}", opcode->get().GetName());
+    }
+
+    return pc;
+}
+
+Node ShaderIR::GetVideoOperand(Node op, bool is_chunk, bool is_signed,
+                               Tegra::Shader::VideoType type, u64 byte_height) {
+    if (!is_chunk) {
+        const auto offset = static_cast<u32>(byte_height * 8);
+        const Node shift = SignedOperation(OperationCode::ILogicalShiftRight, is_signed, NO_PRECISE,
+                                           op, Immediate(offset));
+        return SignedOperation(OperationCode::IBitwiseAnd, is_signed, NO_PRECISE, shift,
+                               Immediate(0xff));
+    }
+    const Node zero = Immediate(0);
+
+    switch (type) {
+    case Tegra::Shader::VideoType::Size16_Low:
+        return SignedOperation(OperationCode::IBitwiseAnd, is_signed, NO_PRECISE, op,
+                               Immediate(0xffff));
+    case Tegra::Shader::VideoType::Size16_High:
+        return SignedOperation(OperationCode::ILogicalShiftRight, is_signed, NO_PRECISE, op,
+                               Immediate(16));
+    case Tegra::Shader::VideoType::Size32:
+        // TODO(Rodrigo): From my hardware tests it becomes a bit "mad" when this type is used
+        // (1 * 1 + 0 == 0x5b800000). Until a better explanation is found: abort.
+        UNIMPLEMENTED();
+        return zero;
+    case Tegra::Shader::VideoType::Invalid:
+        UNREACHABLE_MSG("Invalid instruction encoding");
+        return zero;
+    default:
+        UNREACHABLE();
+        return zero;
+    }
+}
+
+} // namespace VideoCommon::Shader
\ No newline at end of file
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