From 39ab33ee1c976d2653ceef724c0e60ece0c2ba06 Mon Sep 17 00:00:00 2001
From: ReinUsesLisp <reinuseslisp@airmail.cc>
Date: Mon, 22 Jun 2020 20:46:25 -0300
Subject: shader/half_set: Implement HSET2_IMM

Add HSET2_IMM. Due to the complexity of the encoding avoid using
BitField unions and read the relevant bits from the code itself.
This is less error prone.
---
 src/video_core/shader/decode/half_set.cpp | 88 +++++++++++++++++++++++--------
 1 file changed, 67 insertions(+), 21 deletions(-)

(limited to 'src/video_core/shader/decode')

diff --git a/src/video_core/shader/decode/half_set.cpp b/src/video_core/shader/decode/half_set.cpp
index 848e46874..b2e88fa20 100644
--- a/src/video_core/shader/decode/half_set.cpp
+++ b/src/video_core/shader/decode/half_set.cpp
@@ -13,55 +13,101 @@
 
 namespace VideoCommon::Shader {
 
+using std::move;
 using Tegra::Shader::Instruction;
 using Tegra::Shader::OpCode;
+using Tegra::Shader::PredCondition;
 
 u32 ShaderIR::DecodeHalfSet(NodeBlock& bb, u32 pc) {
     const Instruction instr = {program_code[pc]};
     const auto opcode = OpCode::Decode(instr);
 
-    if (instr.hset2.ftz == 0) {
-        LOG_DEBUG(HW_GPU, "{} without FTZ is not implemented", opcode->get().GetName());
+    PredCondition cond;
+    bool bf;
+    bool ftz;
+    bool neg_a;
+    bool abs_a;
+    bool neg_b;
+    bool abs_b;
+    switch (opcode->get().GetId()) {
+    case OpCode::Id::HSET2_C:
+    case OpCode::Id::HSET2_IMM:
+        cond = instr.hsetp2.cbuf_and_imm.cond;
+        bf = instr.Bit(53);
+        ftz = instr.Bit(54);
+        neg_a = instr.Bit(43);
+        abs_a = instr.Bit(44);
+        neg_b = instr.Bit(56);
+        abs_b = instr.Bit(54);
+        break;
+    case OpCode::Id::HSET2_R:
+        cond = instr.hsetp2.reg.cond;
+        bf = instr.Bit(49);
+        ftz = instr.Bit(50);
+        neg_a = instr.Bit(43);
+        abs_a = instr.Bit(44);
+        neg_b = instr.Bit(31);
+        abs_b = instr.Bit(30);
+        break;
+    default:
+        UNREACHABLE();
     }
 
-    Node op_a = UnpackHalfFloat(GetRegister(instr.gpr8), instr.hset2.type_a);
-    op_a = GetOperandAbsNegHalf(op_a, instr.hset2.abs_a, instr.hset2.negate_a);
-
-    Node op_b = [&]() {
+    Node op_b = [this, instr, opcode] {
         switch (opcode->get().GetId()) {
+        case OpCode::Id::HSET2_C:
+            // Inform as unimplemented as this is not tested.
+            UNIMPLEMENTED_MSG("HSET2_C is not implemented");
+            return GetConstBuffer(instr.cbuf34.index, instr.cbuf34.GetOffset());
         case OpCode::Id::HSET2_R:
             return GetRegister(instr.gpr20);
+        case OpCode::Id::HSET2_IMM:
+            return UnpackHalfImmediate(instr, true);
         default:
             UNREACHABLE();
-            return Immediate(0);
+            return Node{};
         }
     }();
-    op_b = UnpackHalfFloat(op_b, instr.hset2.type_b);
-    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);
+    if (!ftz) {
+        LOG_DEBUG(HW_GPU, "{} without FTZ is not implemented", opcode->get().GetName());
+    }
+
+    Node op_a = UnpackHalfFloat(GetRegister(instr.gpr8), instr.hset2.type_a);
+    op_a = GetOperandAbsNegHalf(op_a, abs_a, neg_a);
+
+    switch (opcode->get().GetId()) {
+    case OpCode::Id::HSET2_R:
+        op_b = GetOperandAbsNegHalf(move(op_b), abs_b, neg_b);
+        [[fallthrough]];
+    case OpCode::Id::HSET2_C:
+        op_b = UnpackHalfFloat(move(op_b), instr.hset2.type_b);
+        break;
+    default:
+        break;
+    }
 
-    const Node comparison_pair = GetPredicateComparisonHalf(instr.hset2.cond, op_a, op_b);
+    Node second_pred = GetPredicate(instr.hset2.pred39, instr.hset2.neg_pred);
+
+    Node comparison_pair = GetPredicateComparisonHalf(cond, 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);
+        const u32 raw_value = bf ? 0x3c00 : 0xffff;
+        Node true_value = Immediate(raw_value << (i * 16));
+        Node false_value = Immediate(0);
 
+        Node comparison = Operation(OperationCode::LogicalPick2, comparison_pair, Immediate(i));
+        Node predicate = Operation(combiner, comparison, second_pred);
         values[i] =
-            Operation(OperationCode::Select, NO_PRECISE, predicate, true_value, false_value);
+            Operation(OperationCode::Select, predicate, move(true_value), move(false_value));
     }
 
-    const Node value = Operation(OperationCode::UBitwiseOr, NO_PRECISE, values[0], values[1]);
-    SetRegister(bb, instr.gpr0, value);
+    Node value = Operation(OperationCode::UBitwiseOr, values[0], values[1]);
+    SetRegister(bb, instr.gpr0, move(value));
 
     return pc;
 }
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