shader_decode: Implement EXIT

src/video_core/shader/decode/other.cpp

@@ -16,7 +16,38 @@ u32 ShaderIR::DecodeOther(BasicBlock& bb, u32 pc) {
     const Instruction instr = {program_code[pc]};
     const auto opcode = OpCode::Decode(instr);
 
-    UNIMPLEMENTED();
+    switch (opcode->get().GetId()) {
+    case OpCode::Id::EXIT: {
+        const Tegra::Shader::ConditionCode cc = instr.flow_condition_code;
+        UNIMPLEMENTED_IF_MSG(cc != Tegra::Shader::ConditionCode::T, "EXIT condition code used: {}",
+                             static_cast<u32>(cc));
+
+        switch (instr.flow.cond) {
+        case Tegra::Shader::FlowCondition::Always:
+            bb.push_back(Operation(OperationCode::Exit));
+            if (instr.pred.pred_index == static_cast<u64>(Tegra::Shader::Pred::UnusedIndex)) {
+                // If this is an unconditional exit then just end processing here,
+                // otherwise we have to account for the possibility of the condition
+                // not being met, so continue processing the next instruction.
+                pc = MAX_PROGRAM_LENGTH - 1;
+            }
+            break;
+
+        case Tegra::Shader::FlowCondition::Fcsm_Tr:
+            // TODO(bunnei): What is this used for? If we assume this conditon is not
+            // satisifed, dual vertex shaders in Farming Simulator make more sense
+            UNIMPLEMENTED_MSG("Skipping unknown FlowCondition::Fcsm_Tr");
+            break;
+
+        default:
+            UNIMPLEMENTED_MSG("Unhandled flow condition: {}",
+                              static_cast<u32>(instr.flow.cond.Value()));
+        }
+        break;
+    }
+    default:
+        UNIMPLEMENTED_MSG("Unhandled instruction: {}", opcode->get().GetName());
+    }
 
     return pc;
 }