From b11e0b94c7ce0d965a6149c98c48cda967ec3c04 Mon Sep 17 00:00:00 2001
From: ReinUsesLisp <reinuseslisp@airmail.cc>
Date: Mon, 24 Dec 2018 00:51:52 -0300
Subject: [PATCH] shader_decode: Implement HSET2

---
 src/video_core/shader/decode/half_set.cpp | 44 ++++++++++++++++++++++-
 src/video_core/shader/glsl_decompiler.cpp |  6 ++++
 src/video_core/shader/shader_ir.h         |  1 +
 3 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/src/video_core/shader/decode/half_set.cpp b/src/video_core/shader/decode/half_set.cpp
index af363d5d2..b4ac06144 100644
--- a/src/video_core/shader/decode/half_set.cpp
+++ b/src/video_core/shader/decode/half_set.cpp
@@ -2,6 +2,8 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
+#include <array>
+
 #include "common/assert.h"
 #include "common/common_types.h"
 #include "video_core/engines/shader_bytecode.h"
@@ -16,7 +18,47 @@ u32 ShaderIR::DecodeHalfSet(BasicBlock& bb, u32 pc) {
     const Instruction instr = {program_code[pc]};
     const auto opcode = OpCode::Decode(instr);
 
-    UNIMPLEMENTED();
+    UNIMPLEMENTED_IF(instr.hset2.ftz != 0);
+
+    // instr.hset2.type_a
+    // instr.hset2.type_b
+    Node op_a = GetRegister(instr.gpr8);
+    Node op_b = [&]() {
+        switch (opcode->get().GetId()) {
+        case OpCode::Id::HSET2_R:
+            return GetRegister(instr.gpr20);
+        default:
+            UNREACHABLE();
+            return Immediate(0);
+        }
+    }();
+
+    op_a = GetOperandAbsNegHalf(op_a, instr.hset2.abs_a, instr.hset2.negate_a);
+    op_b = GetOperandAbsNegHalf(op_b, instr.hset2.abs_b, instr.hset2.negate_b);
+
+    const Node second_pred = GetPredicate(instr.hset2.pred39, instr.hset2.neg_pred);
+
+    MetaHalfArithmetic meta{false, {instr.hset2.type_a, instr.hset2.type_b}};
+    const Node comparison_pair = GetPredicateComparisonHalf(instr.hset2.cond, meta, op_a, op_b);
+
+    const OperationCode combiner = GetPredicateCombiner(instr.hset2.op);
+
+    // HSET2 operates on each half float in the pack.
+    std::array<Node, 2> values;
+    for (u32 i = 0; i < 2; ++i) {
+        const u32 raw_value = instr.hset2.bf ? 0x3c00 : 0xffff;
+        const Node true_value = Immediate(raw_value << (i * 16));
+        const Node false_value = Immediate(0);
+
+        const Node comparison =
+            Operation(OperationCode::LogicalPick2, comparison_pair, Immediate(i));
+        const Node predicate = Operation(combiner, comparison, second_pred);
+
+        values[i] = Operation(OperationCode::Select, NO_PRECISE, predicate, true_value, false_value);
+    }
+
+    const Node value = Operation(OperationCode::UBitwiseOr, NO_PRECISE, values[0], values[1]);
+    SetRegister(bb, instr.gpr0, value);
 
     return pc;
 }
diff --git a/src/video_core/shader/glsl_decompiler.cpp b/src/video_core/shader/glsl_decompiler.cpp
index 8a2cc3c31..2e9323df7 100644
--- a/src/video_core/shader/glsl_decompiler.cpp
+++ b/src/video_core/shader/glsl_decompiler.cpp
@@ -1012,6 +1012,11 @@ private:
         return GenerateUnary(operation, "!", Type::Bool, Type::Bool, false);
     }
 
+    std::string LogicalPick2(Operation operation) {
+        const std::string pair = VisitOperand(operation, 0, Type::Bool2);
+        return pair + '[' + VisitOperand(operation, 1, Type::Uint) + ']';
+    }
+
     std::string LogicalAll2(Operation operation) {
         return GenerateUnary(operation, "all", Type::Bool, Type::Bool2);
     }
@@ -1306,6 +1311,7 @@ private:
         &LogicalOr,
         &LogicalXor,
         &LogicalNegate,
+        &LogicalPick2,
         &LogicalAll2,
         &LogicalAny2,
 
diff --git a/src/video_core/shader/shader_ir.h b/src/video_core/shader/shader_ir.h
index 5ef0a7779..69ff18058 100644
--- a/src/video_core/shader/shader_ir.h
+++ b/src/video_core/shader/shader_ir.h
@@ -122,6 +122,7 @@ enum class OperationCode {
     LogicalOr,     /// (bool a, bool b) -> bool
     LogicalXor,    /// (bool a, bool b) -> bool
     LogicalNegate, /// (bool a) -> bool
+    LogicalPick2,  /// (bool2 pair, uint index) -> bool
     LogicalAll2,   /// (bool2 a) -> bool
     LogicalAny2,   /// (bool2 a) -> bool