From 61db05a4127790da3219fccce87c34aa890d1d08 Mon Sep 17 00:00:00 2001
From: Roland Reichwein <mail@reichwein.it>
Date: Mon, 23 Nov 2020 22:01:49 +0100
Subject: Add Subtract, generalized binary operations

---
 asm/intel64/encode.cpp | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

(limited to 'asm/intel64/encode.cpp')

diff --git a/asm/intel64/encode.cpp b/asm/intel64/encode.cpp
index 6118743..d3bfd91 100644
--- a/asm/intel64/encode.cpp
+++ b/asm/intel64/encode.cpp
@@ -83,6 +83,33 @@ std::shared_ptr<Op> makeAddValue(const FlowGraph::Data& data, const FlowGraph::G
   throw std::runtime_error("ICE: Unsupported type for operand data at add: "s + demangle(typeid(data_storage)));
 }
 
+std::shared_ptr<Op> makeSubValue(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());
+
+  return makeOp("sub", Asm::Args{{Asm::Args::Register32("eax"), Asm::Args::Immediate32(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)};
+  return makeOp("sub", Asm::Args{{Asm::Args::Register32("eax"), Asm::Args::Mem32Ptr64("rbp", int32_t(index + 1) * -4)}});
+ } else
+  throw std::runtime_error("ICE: Unsupported type for operand data at sub: "s + demangle(typeid(data_storage)));
+}
+
 std::vector<std::shared_ptr<Chunk>> makeMulValue(const FlowGraph::Data& data, const FlowGraph::Graph& graph)
 {
  if (data.type() != FlowGraph::DataType::Int) {
@@ -192,6 +219,10 @@ void Asm::toMachineCode(const FlowGraph::Graph& graph, Segment& segment)
      segment.push_back(makeLoadValue(operands[1], graph));
      segment.push_back(makeAddValue(operands[2], graph));
      segment.push_back(makeStoreValue(operands[0], graph));
+    } else if (op.type() == FlowGraph::BinaryOperationType::Subtract) {
+     segment.push_back(makeLoadValue(operands[1], graph));
+     segment.push_back(makeSubValue(operands[2], graph));
+     segment.push_back(makeStoreValue(operands[0], graph));
     } else if (op.type() == FlowGraph::BinaryOperationType::Multiply) {
      segment.push_back(makeLoadValue(operands[1], graph));
      segment.append(makeMulValue(operands[2], graph));
-- 
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