From d7b8b5c0b8751caf5b51622f2329b363ecabc267 Mon Sep 17 00:00:00 2001
From: Roland Reichwein <mail@reichwein.it>
Date: Sat, 28 Nov 2020 13:41:39 +0100
Subject: Complete: Shift Left and Shift Right

---
 asm/intel64/encode.cpp | 57 ++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 51 insertions(+), 6 deletions(-)

(limited to 'asm/intel64')

diff --git a/asm/intel64/encode.cpp b/asm/intel64/encode.cpp
index 388639d..c02349c 100644
--- a/asm/intel64/encode.cpp
+++ b/asm/intel64/encode.cpp
@@ -195,13 +195,56 @@ std::vector<std::shared_ptr<Chunk>> makeShiftLeftValue(const FlowGraph::Data& da
 
   index_t index { graph.scope()->indexOfData(data)};
   std::vector<std::shared_ptr<Chunk>> result;
-  result.push_back(makeOp("mov", Asm::Args{{Asm::Args::Register32("ecx"), Asm::Args::Mem32Ptr64("rbp", int32_t(index + 1) * -4)}})); // TODO: limit ecx to 0xff
+  result.push_back(makeOp("mov", Asm::Args{{Asm::Args::Register32("ecx"), Asm::Args::Mem32Ptr64("rbp", int32_t(index + 1) * -4)}}));
+  
+  // limit ecx to 0xff (for saving in cl)
+  result.push_back(makeOp("mov", Asm::Args{{Asm::Args::Register32("edx"), Asm::Args::Immediate32(0xff)}}));
+  result.push_back(makeOp("cmp", Asm::Args{{Asm::Args::Register32("ecx"), Asm::Args::Register32("edx")}}));
+  result.push_back(makeOp("cmova", Asm::Args{{Asm::Args::Register32("ecx"), Asm::Args::Register32("edx")}}));
+  
   result.push_back(makeOp("shl", Asm::Args{{Asm::Args::Register32("eax"), Asm::Args::Register8("cl")}}));
   return result;
  } else
   throw std::runtime_error("ICE: Unsupported type for operand data at shift left: "s + demangle(typeid(data_storage)));
 }
 
+std::vector<std::shared_ptr<Chunk>> makeShiftRightValue(const FlowGraph::Data& data, const FlowGraph::Graph& graph)
+{
+ if (data.type() != FlowGraph::DataType::Int) {
+  throw std::runtime_error("Bad type for operand: "s + std::to_string(int(data.type())));
+ }
+
+ if (!data.storage())
+  throw std::runtime_error("ICE: Operand storage is 0");
+
+ auto& data_storage{*data.storage()};
+ if (typeid(data_storage) == typeid(FlowGraph::Constant)) {
+  FlowGraph::Constant& value {dynamic_cast<FlowGraph::Constant&>(data_storage)};
+  if (value.value().size() < sizeof(uint32_t))
+   throw std::runtime_error("ICE: Int data from operand needs at least 4 bytes, got "s + std::to_string(value.value().size()));
+
+  uint32_t immediate = endian::from_little32(value.value());
+  immediate = std::min(immediate, uint32_t(0xFF));
+
+  return {makeOp("shr", Asm::Args{{Asm::Args::Register32("eax"), Asm::Args::Immediate8(static_cast<uint8_t>(immediate))}})};
+ } else if (typeid(data_storage) == typeid(FlowGraph::TemporaryStorage)) {
+  //FlowGraph::TemporaryStorage& storage {dynamic_cast<FlowGraph::TemporaryStorage&>(data_storage)};
+
+  index_t index { graph.scope()->indexOfData(data)};
+  std::vector<std::shared_ptr<Chunk>> result;
+  result.push_back(makeOp("mov", Asm::Args{{Asm::Args::Register32("ecx"), Asm::Args::Mem32Ptr64("rbp", int32_t(index + 1) * -4)}}));
+  
+  // limit ecx to 0xff (for saving in cl)
+  result.push_back(makeOp("mov", Asm::Args{{Asm::Args::Register32("edx"), Asm::Args::Immediate32(0xff)}}));
+  result.push_back(makeOp("cmp", Asm::Args{{Asm::Args::Register32("ecx"), Asm::Args::Register32("edx")}}));
+  result.push_back(makeOp("cmova", Asm::Args{{Asm::Args::Register32("ecx"), Asm::Args::Register32("edx")}}));
+  
+  result.push_back(makeOp("shr", Asm::Args{{Asm::Args::Register32("eax"), Asm::Args::Register8("cl")}}));
+  return result;
+ } else
+  throw std::runtime_error("ICE: Unsupported type for operand data at shift right: "s + demangle(typeid(data_storage)));
+}
+
 } // namespace
 
 void Asm::toMachineCode(const FlowGraph::Graph& graph, Segment& segment)
@@ -225,11 +268,9 @@ void Asm::toMachineCode(const FlowGraph::Graph& graph, Segment& segment)
      segment.push_back(makeStoreValue(operands[0], graph));
     } else if (op.type() == FlowGraph::UnaryOperationType::LogicalNot) {
      segment.push_back(makeLoadValue(operands[1], graph));
-     // TODO: cmp eax, 0 \n sete al \n movsx eax, al
-     segment.append(parseAsm("bsr eax")); // ZF=1 iff eax=0
-     segment.append(parseAsm("lahf")); // ZF in AH bit 6
-     segment.append(parseAsm("shr eax, 14")); // ZF in eax bit 0
-     segment.append(parseAsm("and eax, 1")); // now, 0 or 1 is in eax, negated because of zero flag
+     segment.append(parseAsm("cmp eax, 0"));
+     segment.append(parseAsm("sete al"));
+     segment.append(parseAsm("movsx eax, al"));
      segment.push_back(makeStoreValue(operands[0], graph));
     } else if (op.type() == FlowGraph::UnaryOperationType::Minus) {
      segment.push_back(makeLoadValue(operands[1], graph));
@@ -275,6 +316,10 @@ void Asm::toMachineCode(const FlowGraph::Graph& graph, Segment& segment)
      segment.push_back(makeLoadValue(operands[1], graph));
      segment.append(makeShiftLeftValue(operands[2], graph));
      segment.push_back(makeStoreValue(operands[0], graph));
+    } else if (op.type() == FlowGraph::BinaryOperationType::ShiftRight) {
+     segment.push_back(makeLoadValue(operands[1], graph));
+     segment.append(makeShiftRightValue(operands[2], graph));
+     segment.push_back(makeStoreValue(operands[0], graph));
     } else
      throw std::runtime_error("ICE: Asm: Unsupported binary operation type: "s + std::to_string(static_cast<int>(op.type())));
 
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