shader: Initial recompiler work

src/shader_recompiler/frontend/maxwell/termination_code.cpp

@@ -0,0 +1,79 @@
+// Copyright 2021 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <span>
+
+#include "shader_recompiler/exception.h"
+#include "shader_recompiler/frontend/ir/basic_block.h"
+#include "shader_recompiler/frontend/ir/ir_emitter.h"
+#include "shader_recompiler/frontend/maxwell/control_flow.h"
+#include "shader_recompiler/frontend/maxwell/termination_code.h"
+
+namespace Shader::Maxwell {
+
+static void EmitExit(IR::IREmitter& ir) {
+    ir.Exit();
+}
+
+static IR::U1 GetFlowTest(IR::FlowTest flow_test, IR::IREmitter& ir) {
+    switch (flow_test) {
+    case IR::FlowTest::T:
+        return ir.Imm1(true);
+    case IR::FlowTest::F:
+        return ir.Imm1(false);
+    case IR::FlowTest::NE:
+        // FIXME: Verify this
+        return ir.LogicalNot(ir.GetZFlag());
+    case IR::FlowTest::NaN:
+        // FIXME: Verify this
+        return ir.LogicalAnd(ir.GetSFlag(), ir.GetZFlag());
+    default:
+        throw NotImplementedException("Flow test {}", flow_test);
+    }
+}
+
+static IR::U1 GetCond(IR::Condition cond, IR::IREmitter& ir) {
+    const IR::FlowTest flow_test{cond.FlowTest()};
+    const auto [pred, pred_negated]{cond.Pred()};
+    if (pred == IR::Pred::PT && !pred_negated) {
+        return GetFlowTest(flow_test, ir);
+    }
+    if (flow_test == IR::FlowTest::T) {
+        return ir.GetPred(pred, pred_negated);
+    }
+    return ir.LogicalAnd(ir.GetPred(pred, pred_negated), GetFlowTest(flow_test, ir));
+}
+
+static void EmitBranch(const Flow::Block& flow_block, std::span<IR::Block* const> block_map,
+                       IR::IREmitter& ir) {
+    if (flow_block.cond == true) {
+        return ir.Branch(block_map[flow_block.branch_true]);
+    }
+    if (flow_block.cond == false) {
+        return ir.Branch(block_map[flow_block.branch_false]);
+    }
+    return ir.BranchConditional(GetCond(flow_block.cond, ir), block_map[flow_block.branch_true],
+                                block_map[flow_block.branch_false]);
+}
+
+void EmitTerminationCode(const Flow::Block& flow_block, std::span<IR::Block* const> block_map) {
+    IR::Block* const block{block_map[flow_block.id]};
+    IR::IREmitter ir(*block);
+    switch (flow_block.end_class) {
+    case Flow::EndClass::Branch:
+        EmitBranch(flow_block, block_map, ir);
+        break;
+    case Flow::EndClass::Exit:
+        EmitExit(ir);
+        break;
+    case Flow::EndClass::Return:
+        ir.Return();
+        break;
+    case Flow::EndClass::Unreachable:
+        ir.Unreachable();
+        break;
+    }
+}
+
+} // namespace Shader::Maxwell