fix(evm): fix interpreter exp gas

src/evm/evm.h

@@ -24,6 +24,9 @@ constexpr auto CALL_VALUE_COST = 9000;
 constexpr auto ACCOUNT_CREATION_COST = 25000;
 constexpr auto CALL_GAS_STIPEND = 2300;
 constexpr uint64_t LegacyModExpBaseGas = 600;
+constexpr auto EXP_BYTE_GAS = 50;
+constexpr auto EXP_BYTE_GAS_PRE_SPURIOUS_DRAGON = 10;
+
 /// The limit of the size of created contract
 /// defined by [EIP-170](https://eips.ethereum.org/EIPS/eip-170)
 constexpr auto MAX_CODE_SIZE = 0x6000;

src/evm/opcode_handlers.cpp

@@ -64,7 +64,6 @@ DEFINE_CALCULATE_GAS(Sub, OP_SUB);
 DEFINE_CALCULATE_GAS(Mul, OP_MUL);
 DEFINE_CALCULATE_GAS(Div, OP_DIV);
 DEFINE_CALCULATE_GAS(Mod, OP_MOD);
-DEFINE_CALCULATE_GAS(Exp, OP_EXP);
 DEFINE_CALCULATE_GAS(SDiv, OP_SDIV);
 DEFINE_CALCULATE_GAS(SMod, OP_SMOD);
 
@@ -92,6 +91,7 @@ DEFINE_CALCULATE_GAS(Sgt, OP_SGT);
 DEFINE_NOT_TEMPLATE_CALCULATE_GAS(SignExtend, OP_SIGNEXTEND);
 DEFINE_NOT_TEMPLATE_CALCULATE_GAS(Byte, OP_BYTE);
 DEFINE_NOT_TEMPLATE_CALCULATE_GAS(Sar, OP_SAR);
+DEFINE_NOT_TEMPLATE_CALCULATE_GAS(Exp, OP_EXP);
 
 // Environmental information
 DEFINE_NOT_TEMPLATE_CALCULATE_GAS(Address, OP_ADDRESS);
@@ -348,6 +348,26 @@ void SarHandler::doExecute() {
   }
   Frame->push(Res);
 }
+
+void ExpHandler::doExecute() {
+  auto *Frame = getFrame();
+  auto *Context = getContext();
+  EVM_STACK_CHECK(Frame, 2);
+
+  auto &A = Frame->Stack[Frame->Sp - 1];
+  auto &B = Frame->Stack[Frame->Sp - 2];
+  uint64_t BytesNum = intx::count_significant_bytes(B);
+  uint64_t ByteGas = currentRevision() < EVMC_SPURIOUS_DRAGON
+                         ? EXP_BYTE_GAS_PRE_SPURIOUS_DRAGON
+                         : EXP_BYTE_GAS;
+  if (!chargeGas(Frame, BytesNum * ByteGas)) {
+    Context->setStatus(EVMC_OUT_OF_GAS);
+    return;
+  }
+  B = intx::exp(A, B);
+  --Frame->Sp;
+}
+
 // environmental information operations
 void AddressHandler::doExecute() {
   auto *Frame = getFrame();

src/evm/opcode_handlers.h

@@ -170,7 +170,6 @@ DEFINE_BINARY_OP(Sub, (A - B));
 DEFINE_BINARY_OP(Mul, (A * B));
 DEFINE_BINARY_OP(Div, ((B == 0) ? intx::uint256(0) : (A / B)));
 DEFINE_BINARY_OP(Mod, ((B == 0) ? intx::uint256(0) : A % B));
-DEFINE_BINARY_OP(Exp, intx::exp(A, B));
 DEFINE_BINARY_OP(SDiv,
                  ((B == 0) ? intx::uint256(0) : intx::sdivrem(A, B).quot));
 DEFINE_BINARY_OP(SMod, ((B == 0) ? intx::uint256(0) : intx::sdivrem(A, B).rem));
@@ -257,6 +256,7 @@ DEFINE_UNIMPLEMENT_HANDLER(SStore);
 DEFINE_UNIMPLEMENT_HANDLER(SignExtend);
 DEFINE_UNIMPLEMENT_HANDLER(Byte);
 DEFINE_UNIMPLEMENT_HANDLER(Sar);
+DEFINE_UNIMPLEMENT_HANDLER(Exp);
 
 // Memory operations
 DEFINE_UNIMPLEMENT_HANDLER(MStore);

tests/evmone_unittests/EVMOneInterpreterUnitTestsRunList.txt

@@ -200,3 +200,6 @@ multi_vm/evm.sload_cost_pre_tangerine_whistle/external_vm
 multi_vm/evm.staticcall_then_oog/external_vm
 multi_vm/evm.staticmode/external_vm
 multi_vm/evm.storage/external_vm
+multi_vm/evm.exp/external_vm
+multi_vm/evm.exp_oog/external_vm
+multi_vm/evm.exp_pre_spurious_dragon/external_vm