Basic control flow skeleton and jumps implemented.

A-train's trees draw right now!
Helps a bit with #473 but still need to implement loops.

src/xenia/gpu/glsl_shader_translator.cc

@@ -287,23 +287,50 @@ void main() {
   EmitSource("  vec4 src0;\n");
   EmitSource("  vec4 src1;\n");
   EmitSource("  vec4 src2;\n");
+
+  // Master loop and switch for flow control.
+  EmitSourceDepth("int pc = 0;\n");
+  EmitSourceDepth("while (pc != 0xFFFF) {\n");
+  Indent();
+  EmitSourceDepth("switch (pc) {\n");
 }
 
 std::vector<uint8_t> GlslShaderTranslator::CompleteTranslation() {
+  // End of master switch.
+  EmitSourceDepth("default: pc = 0xFFFF; break;\n");
+  EmitSourceDepth("};  // switch\n");
+  Unindent();
+  EmitSourceDepth("}  // while\n");
+
   // End of process*() function.
   EmitSource("}\n");
 
   return source_.ToBytes();
 }
 
-void GlslShaderTranslator::ProcessLabel(uint32_t cf_index) {
+void GlslShaderTranslator::ProcessLabel(uint32_t cf_index) {}
-  EmitUnimplementedTranslationError();
-}
 
 void GlslShaderTranslator::ProcessControlFlowNopInstruction() {
   EmitSource("//        cnop\n");
 }
 
+void GlslShaderTranslator::ProcessControlFlowInstructionBegin(
+    uint32_t cf_index) {
+  cf_wrote_pc_ = false;
+  EmitSourceDepth("case 0x%X:  // L%d\n", cf_index, cf_index);
+  Indent();
+}
+
+void GlslShaderTranslator::ProcessControlFlowInstructionEnd(uint32_t cf_index) {
+  if (!cf_wrote_pc_) {
+    uint32_t next_index = cf_index + 1;
+    EmitSourceDepth("pc = 0x%X;  // Fallthrough to L%d\n", next_index,
+                    next_index);
+  }
+  EmitSourceDepth("break;\n");
+  Unindent();
+}
+
 void GlslShaderTranslator::ProcessExecInstructionBegin(
     const ParsedExecInstruction& instr) {
   EmitSource("// ");
@@ -330,6 +357,10 @@ void GlslShaderTranslator::ProcessExecInstructionEnd(
     const ParsedExecInstruction& instr) {
   Unindent();
   EmitSourceDepth("}\n");
+  if (instr.is_end) {
+    EmitSourceDepth("pc = 0xFFFF;\n");
+    cf_wrote_pc_ = true;
+  }
 }
 
 void GlslShaderTranslator::ProcessLoopStartInstruction(
@@ -369,7 +400,39 @@ void GlslShaderTranslator::ProcessJumpInstruction(
   EmitSource("// ");
   instr.Disassemble(&source_);
 
-  EmitUnimplementedTranslationError();
+  bool needs_fallthrough = false;
+  switch (instr.type) {
+    case ParsedJumpInstruction::Type::kUnconditional:
+      EmitSourceDepth("{\n");
+      break;
+    case ParsedJumpInstruction::Type::kConditional:
+      EmitSourceDepth("if ((state.bool_consts[%d] & (1 << %d)) == %c) {\n",
+                      instr.bool_constant_index / 32,
+                      instr.bool_constant_index % 32,
+                      instr.condition ? '1' : '0');
+      needs_fallthrough = true;
+      break;
+    case ParsedJumpInstruction::Type::kPredicated:
+      EmitSourceDepth("if (%cp0) {\n", instr.condition ? ' ' : '!');
+      needs_fallthrough = true;
+      break;
+  }
+  Indent();
+
+  EmitSourceDepth("pc = 0x%X;  // L%d\n", instr.target_address,
+                  instr.target_address);
+  cf_wrote_pc_ = true;
+
+  Unindent();
+  if (needs_fallthrough) {
+    uint32_t next_address = instr.dword_index + 1;
+    EmitSourceDepth("} else {\n");
+    EmitSourceDepth("  pc = 0x%X;  // Fallthrough to L%d\n", next_address,
+                    next_address);
+    EmitSourceDepth("}\n");
+  } else {
+    EmitSourceDepth("}\n");
+  }
 }
 
 void GlslShaderTranslator::ProcessAllocInstruction(

src/xenia/gpu/glsl_shader_translator.h

@@ -40,6 +40,8 @@ class GlslShaderTranslator : public ShaderTranslator {
 
   void ProcessLabel(uint32_t cf_index) override;
   void ProcessControlFlowNopInstruction() override;
+  void ProcessControlFlowInstructionBegin(uint32_t cf_index) override;
+  void ProcessControlFlowInstructionEnd(uint32_t cf_index) override;
   void ProcessExecInstructionBegin(const ParsedExecInstruction& instr) override;
   void ProcessExecInstructionEnd(const ParsedExecInstruction& instr) override;
   void ProcessLoopStartInstruction(
@@ -70,6 +72,7 @@ class GlslShaderTranslator : public ShaderTranslator {
   StringBuffer source_;
   int depth_ = 0;
   char depth_prefix_[16] = {0};
+  bool cf_wrote_pc_ = false;
 
   void ProcessVectorAluInstruction(const ParsedAluInstruction& instr);
   void ProcessScalarAluInstruction(const ParsedAluInstruction& instr);

src/xenia/gpu/shader.h

@@ -195,6 +195,8 @@ struct ParsedExecInstruction {
   // Required condition value of the comparision (true or false).
   bool condition = false;
 
+  // Whether this exec ends the shader.
+  bool is_end = false;
   // Whether to reset the current predicate.
   bool clean = true;
   // ?

src/xenia/gpu/shader_translator.cc

@@ -303,22 +303,28 @@ bool ShaderTranslator::TranslateBlocks() {
     ControlFlowInstruction cf_b;
     UnpackControlFlowInstructions(ucode_dwords_ + i, &cf_a, &cf_b);
 
+    cf_index_ = cf_index;
     MarkUcodeInstruction(i);
     if (label_addresses.count(cf_index)) {
       AppendUcodeDisasmFormat("                label L%u\n", cf_index);
       ProcessLabel(cf_index);
     }
     AppendUcodeDisasmFormat("/* %4u.0 */ ", cf_index / 2);
+    ProcessControlFlowInstructionBegin(cf_index);
     TranslateControlFlowInstruction(cf_a);
+    ProcessControlFlowInstructionEnd(cf_index);
     ++cf_index;
 
+    cf_index_ = cf_index;
     MarkUcodeInstruction(i);
     if (label_addresses.count(cf_index)) {
       AppendUcodeDisasmFormat("                label L%u\n", cf_index);
       ProcessLabel(cf_index);
     }
     AppendUcodeDisasmFormat("/* %4u.1 */ ", cf_index / 2);
+    ProcessControlFlowInstructionBegin(cf_index);
     TranslateControlFlowInstruction(cf_b);
+    ProcessControlFlowInstructionEnd(cf_index);
     ++cf_index;
   }
 
@@ -399,12 +405,13 @@ void ShaderTranslator::TranslateControlFlowNop(
 void ShaderTranslator::TranslateControlFlowExec(
     const ControlFlowExecInstruction& cf) {
   ParsedExecInstruction i;
-  i.dword_index = 0;
+  i.dword_index = cf_index_;
   i.opcode = cf.opcode();
   i.opcode_name = cf.opcode() == ControlFlowOpcode::kExecEnd ? "exece" : "exec";
   i.instruction_address = cf.address();
   i.instruction_count = cf.count();
   i.type = ParsedExecInstruction::Type::kUnconditional;
+  i.is_end = cf.opcode() == ControlFlowOpcode::kExecEnd;
   i.clean = cf.clean();
   i.is_yield = cf.is_yield();
   i.sequence = cf.sequence();
@@ -415,13 +422,14 @@ void ShaderTranslator::TranslateControlFlowExec(
 void ShaderTranslator::TranslateControlFlowCondExec(
     const ControlFlowCondExecInstruction& cf) {
   ParsedExecInstruction i;
-  i.dword_index = 0;
+  i.dword_index = cf_index_;
   i.opcode = cf.opcode();
   i.opcode_name = "cexec";
   switch (cf.opcode()) {
     case ControlFlowOpcode::kCondExecEnd:
     case ControlFlowOpcode::kCondExecPredCleanEnd:
       i.opcode_name = "cexece";
+      i.is_end = true;
       break;
   }
   i.instruction_address = cf.address();
@@ -444,7 +452,7 @@ void ShaderTranslator::TranslateControlFlowCondExec(
 void ShaderTranslator::TranslateControlFlowCondExecPred(
     const ControlFlowCondExecPredInstruction& cf) {
   ParsedExecInstruction i;
-  i.dword_index = 0;
+  i.dword_index = cf_index_;
   i.opcode = cf.opcode();
   i.opcode_name =
       cf.opcode() == ControlFlowOpcode::kCondExecPredEnd ? "exece" : "exec";
@@ -452,6 +460,7 @@ void ShaderTranslator::TranslateControlFlowCondExecPred(
   i.instruction_count = cf.count();
   i.type = ParsedExecInstruction::Type::kPredicated;
   i.condition = cf.condition();
+  i.is_end = cf.opcode() == ControlFlowOpcode::kCondExecPredEnd;
   i.clean = cf.clean();
   i.is_yield = cf.is_yield();
   i.sequence = cf.sequence();
@@ -462,7 +471,7 @@ void ShaderTranslator::TranslateControlFlowCondExecPred(
 void ShaderTranslator::TranslateControlFlowLoopStart(
     const ControlFlowLoopStartInstruction& cf) {
   ParsedLoopStartInstruction i;
-  i.dword_index = 0;
+  i.dword_index = cf_index_;
   i.loop_constant_index = cf.loop_id();
   i.is_repeat = cf.is_repeat();
   i.loop_skip_address = cf.address();
@@ -475,7 +484,7 @@ void ShaderTranslator::TranslateControlFlowLoopStart(
 void ShaderTranslator::TranslateControlFlowLoopEnd(
     const ControlFlowLoopEndInstruction& cf) {
   ParsedLoopEndInstruction i;
-  i.dword_index = 0;
+  i.dword_index = cf_index_;
   i.is_predicated_break = cf.is_predicated_break();
   i.predicate_condition = cf.condition();
   i.loop_constant_index = cf.loop_id();
@@ -489,7 +498,7 @@ void ShaderTranslator::TranslateControlFlowLoopEnd(
 void ShaderTranslator::TranslateControlFlowCondCall(
     const ControlFlowCondCallInstruction& cf) {
   ParsedCallInstruction i;
-  i.dword_index = 0;
+  i.dword_index = cf_index_;
   i.target_address = cf.address();
   if (cf.is_unconditional()) {
     i.type = ParsedCallInstruction::Type::kUnconditional;
@@ -510,7 +519,7 @@ void ShaderTranslator::TranslateControlFlowCondCall(
 void ShaderTranslator::TranslateControlFlowReturn(
     const ControlFlowReturnInstruction& cf) {
   ParsedReturnInstruction i;
-  i.dword_index = 0;
+  i.dword_index = cf_index_;
 
   i.Disassemble(&ucode_disasm_buffer_);
 
@@ -520,7 +529,7 @@ void ShaderTranslator::TranslateControlFlowReturn(
 void ShaderTranslator::TranslateControlFlowCondJmp(
     const ControlFlowCondJmpInstruction& cf) {
   ParsedJumpInstruction i;
-  i.dword_index = 0;
+  i.dword_index = cf_index_;
   i.target_address = cf.address();
   if (cf.is_unconditional()) {
     i.type = ParsedJumpInstruction::Type::kUnconditional;
@@ -541,7 +550,7 @@ void ShaderTranslator::TranslateControlFlowCondJmp(
 void ShaderTranslator::TranslateControlFlowAlloc(
     const ControlFlowAllocInstruction& cf) {
   ParsedAllocInstruction i;
-  i.dword_index = 0;
+  i.dword_index = cf_index_;
   i.type = cf.alloc_type();
   i.count = cf.size();
   i.is_vertex_shader = is_vertex_shader();

src/xenia/gpu/shader_translator.h

@@ -74,6 +74,11 @@ class ShaderTranslator {
 
   // Handles translation for control flow nop instructions.
   virtual void ProcessControlFlowNopInstruction() {}
+  // Handles the start of a control flow instruction at the given address.
+  virtual void ProcessControlFlowInstructionBegin(uint32_t cf_index) {}
+  // Handles the end of a control flow instruction that began at the given
+  // address.
+  virtual void ProcessControlFlowInstructionEnd(uint32_t cf_index) {}
   // Handles translation for control flow exec instructions prior to their
   // contained ALU/fetch instructions.
   virtual void ProcessExecInstructionBegin(const ParsedExecInstruction& instr) {
@@ -166,6 +171,9 @@ class ShaderTranslator {
   // Accumulated translation errors.
   std::vector<Shader::Error> errors_;
 
+  // Current control flow dword index.
+  uint32_t cf_index_ = 0;
+
   // Microcode disassembly buffer, accumulated throughout the translation.
   StringBuffer ucode_disasm_buffer_;
   // Current line number in the disasm, which can be used for source annotation.