From 2031240485a4290345ad2828d84477767b0b1a68 Mon Sep 17 00:00:00 2001
From: artur-zawlocki <artur.zawlocki@gmail.com>
Date: Mon, 13 Oct 2014 17:22:56 +0100
Subject: [PATCH] Implemented ADDMOD, MULMOD and GAS [Delivers #80566276]

---
 evmcc/Compiler.cpp          | 30 ++++++++++++++++++++++++++++++
 evmcc/GasMeter.cpp          |  7 ++++++-
 evmcc/GasMeter.h            |  2 ++
 evmcc/test/arith/addmod.evm |  1 +
 evmcc/test/arith/addmod.lll | 12 ++++++++++++
 evmcc/test/arith/mulmod.evm |  1 +
 evmcc/test/arith/mulmod.lll | 12 ++++++++++++
 7 files changed, 64 insertions(+), 1 deletion(-)
 create mode 100644 evmcc/test/arith/addmod.evm
 create mode 100644 evmcc/test/arith/addmod.lll
 create mode 100644 evmcc/test/arith/mulmod.evm
 create mode 100644 evmcc/test/arith/mulmod.lll

diff --git a/evmcc/Compiler.cpp b/evmcc/Compiler.cpp
index 91758984d..b5270d85a 100644
--- a/evmcc/Compiler.cpp
+++ b/evmcc/Compiler.cpp
@@ -434,6 +434,36 @@ std::unique_ptr<llvm::Module> Compiler::compile(const dev::bytes& bytecode)
 				break;
 			}
 
+			case Instruction::ADDMOD:
+			{
+				auto val1 = stack.pop();
+				auto val2 = stack.pop();
+				auto sum = builder.CreateAdd(val1, val2);
+				auto mod = stack.pop();
+
+				auto sum128 = builder.CreateTrunc(sum, Type::lowPrecision);
+				auto mod128 = builder.CreateTrunc(mod, Type::lowPrecision);
+				auto res128 = builder.CreateURem(sum128, mod128);
+				auto res256 = builder.CreateZExt(res128, Type::i256);
+				stack.push(res256);
+				break;
+			}
+
+			case Instruction::MULMOD:
+			{
+				auto val1 = stack.pop();
+				auto val2 = stack.pop();
+				auto prod = builder.CreateMul(val1, val2);
+				auto mod = stack.pop();
+
+				auto prod128 = builder.CreateTrunc(prod, Type::lowPrecision);
+				auto mod128 = builder.CreateTrunc(mod, Type::lowPrecision);
+				auto res128 = builder.CreateURem(prod128, mod128);
+				auto res256 = builder.CreateZExt(res128, Type::i256);
+				stack.push(res256);
+				break;
+			}
+
 			case Instruction::SHA3:
 			{
 				auto inOff = stack.pop();
diff --git a/evmcc/GasMeter.cpp b/evmcc/GasMeter.cpp
index 13d81b080..918be7bf7 100644
--- a/evmcc/GasMeter.cpp
+++ b/evmcc/GasMeter.cpp
@@ -130,4 +130,9 @@ void GasMeter::checkMemory(llvm::Value* _additionalMemoryInWords, llvm::IRBuilde
 	_builder.CreateCall(m_gasCheckFunc, cost);
 }
 
-}
\ No newline at end of file
+llvm::GlobalVariable* GasMeter::getLLVMGasVar()
+{
+	return m_gas;
+}
+
+}
diff --git a/evmcc/GasMeter.h b/evmcc/GasMeter.h
index 1fcbe6459..c3ea9f84f 100644
--- a/evmcc/GasMeter.h
+++ b/evmcc/GasMeter.h
@@ -25,6 +25,8 @@ public:
 	/// Generate code that checks the cost of additional memory used by program
 	void checkMemory(llvm::Value* _additionalMemoryInWords, llvm::IRBuilder<>& _builder);
 
+	llvm::GlobalVariable* getLLVMGasVar();
+
 private:
 	/// Cumulative gas cost of a block of instructions
 	/// @TODO Handle overflow
diff --git a/evmcc/test/arith/addmod.evm b/evmcc/test/arith/addmod.evm
new file mode 100644
index 000000000..4ca71e065
--- /dev/null
+++ b/evmcc/test/arith/addmod.evm
@@ -0,0 +1 @@
+60646107b760271460005560006001f2
diff --git a/evmcc/test/arith/addmod.lll b/evmcc/test/arith/addmod.lll
new file mode 100644
index 000000000..11a6b2cb9
--- /dev/null
+++ b/evmcc/test/arith/addmod.lll
@@ -0,0 +1,12 @@
+;; Should return (1975 + 39) `mod` 100  = 14 = 0x0e
+(asm
+100
+1975
+39
+ADDMOD
+0 
+MSTORE8 
+0
+1
+RETURN
+)
\ No newline at end of file
diff --git a/evmcc/test/arith/mulmod.evm b/evmcc/test/arith/mulmod.evm
new file mode 100644
index 000000000..e34a06154
--- /dev/null
+++ b/evmcc/test/arith/mulmod.evm
@@ -0,0 +1 @@
+6064601b60251560005560006001f2
diff --git a/evmcc/test/arith/mulmod.lll b/evmcc/test/arith/mulmod.lll
new file mode 100644
index 000000000..5e87f0843
--- /dev/null
+++ b/evmcc/test/arith/mulmod.lll
@@ -0,0 +1,12 @@
+;; Should return (27 * 37) `mod` 100  = 99 = 0x63
+(asm
+100
+27
+37
+MULMOD
+0 
+MSTORE8 
+0
+1
+RETURN
+)
\ No newline at end of file