shader_decode: Implement R2P

src/video_core/shader/decode/register_set_predicate.cpp

@@ -16,7 +16,34 @@ u32 ShaderIR::DecodeRegisterSetPredicate(BasicBlock& bb, u32 pc) {
     const Instruction instr = {program_code[pc]};
     const auto opcode = OpCode::Decode(instr);
 
-    UNIMPLEMENTED();
+    UNIMPLEMENTED_IF(instr.r2p.mode != Tegra::Shader::R2pMode::Pr);
+
+    const Node apply_mask = [&]() {
+        switch (opcode->get().GetId()) {
+        case OpCode::Id::R2P_IMM:
+            return Immediate(static_cast<u32>(instr.r2p.immediate_mask));
+        default:
+            UNREACHABLE();
+            return Immediate(static_cast<u32>(instr.r2p.immediate_mask));
+        }
+    }();
+    const Node mask =
+        Operation(OperationCode::ULogicalShiftRight, NO_PRECISE, GetRegister(instr.gpr8),
+                  Immediate(static_cast<u32>(instr.r2p.byte)));
+
+    constexpr u32 programmable_preds = 7;
+    for (u64 pred = 0; pred < programmable_preds; ++pred) {
+        const Node shift = Immediate(1u << static_cast<u32>(pred));
+
+        const Node apply_compare = Operation(OperationCode::UBitwiseAnd, NO_PRECISE, apply_mask, shift);
+        const Node condition = Operation(OperationCode::LogicalUEqual, apply_compare, Immediate(0));
+
+        const Node value_compare = Operation(OperationCode::UBitwiseAnd, NO_PRECISE, mask, shift);
+        const Node value = Operation(OperationCode::LogicalUEqual, value_compare, Immediate(0));
+
+        const Node code = Operation(OperationCode::LogicalAssign, GetPredicate(pred), value);
+        bb.push_back(Conditional(condition, {code}));
+    }
 
     return pc;
 }