From 05e9b891f08975dbe0484e8ded5a2f408d556677 Mon Sep 17 00:00:00 2001
From: jangko <jangko128@gmail.com>
Date: Sun, 27 Jun 2021 20:18:17 +0700
Subject: [PATCH] EIP-3198: add baseFee op code in nim-evm

---
 nimbus/transaction/host_services.nim    | 1 +
 nimbus/vm/computation.nim               | 6 ++++++
 nimbus/vm/interpreter/gas_costs.nim     | 1 +
 nimbus/vm/interpreter/opcode_values.nim | 1 +
 nimbus/vm/interpreter/opcodes_impl.nim  | 4 ++++
 nimbus/vm/interpreter_dispatch.nim      | 1 +
 nimbus/vm/state.nim                     | 3 +++
 7 files changed, 17 insertions(+)

diff --git a/nimbus/transaction/host_services.nim b/nimbus/transaction/host_services.nim
index 2af43c76c..3110f1508 100644
--- a/nimbus/transaction/host_services.nim
+++ b/nimbus/transaction/host_services.nim
@@ -63,6 +63,7 @@ proc setupTxContext(host: TransactionHost) =
   # vmState.difficulty now unused
   host.txContext.block_difficulty = vmState.blockHeader.difficulty.toEvmc
   host.txContext.chain_id         = vmState.chaindb.config.chainId.uint.u256.toEvmc
+  host.txContext.block_base_fee   = vmState.blockHeader.baseFee.toEvmc
 
 const use_evmc_glue = defined(evmc_enabled)
 
diff --git a/nimbus/vm/computation.nim b/nimbus/vm/computation.nim
index 9295fa682..d600794a3 100644
--- a/nimbus/vm/computation.nim
+++ b/nimbus/vm/computation.nim
@@ -57,6 +57,12 @@ template getGasLimit*(c: Computation): GasInt =
   else:
     c.vmState.gasLimit
 
+template getBaseFee*(c: Computation): Uint256 =
+  when evmc_enabled:
+    Uint256.fromEvmc c.host.getTxContext().block_base_fee
+  else:
+    c.vmState.baseFee
+
 template getChainId*(c: Computation): uint =
   when evmc_enabled:
     Uint256.fromEvmc(c.host.getTxContext().chain_id).truncate(uint)
diff --git a/nimbus/vm/interpreter/gas_costs.nim b/nimbus/vm/interpreter/gas_costs.nim
index 78eb96cec..d3b2fd01e 100644
--- a/nimbus/vm/interpreter/gas_costs.nim
+++ b/nimbus/vm/interpreter/gas_costs.nim
@@ -537,6 +537,7 @@ template gasCosts(fork: Fork, prefix, ResultGasCostsName: untyped) =
           GasLimit:        fixed GasBase,
           ChainIdOp:       fixed GasBase,
           SelfBalance:     fixed GasLow,
+          BaseFee:         fixed GasBase,
 
           # 50s: Stack, Memory, Storage and Flow Operations
           Pop:            fixed GasBase,
diff --git a/nimbus/vm/interpreter/opcode_values.nim b/nimbus/vm/interpreter/opcode_values.nim
index 7ecbce36a..643b5fce3 100644
--- a/nimbus/vm/interpreter/opcode_values.nim
+++ b/nimbus/vm/interpreter/opcode_values.nim
@@ -81,6 +81,7 @@ fill_enum_holes:
 
       ChainIdOp =      0x46, # Get current chain’s EIP-155 unique identifier.
       SelfBalance =    0x47, # Get current contract's balance.
+      BaseFee =        0x48, # Get block’s base fee. EIP-3198
 
       # 50s: Stack, Memory, Storage and Flow Operations
       Pop =            0x50, # Remove item from stack.
diff --git a/nimbus/vm/interpreter/opcodes_impl.nim b/nimbus/vm/interpreter/opcodes_impl.nim
index e0c405cac..d1fa1e8c1 100644
--- a/nimbus/vm/interpreter/opcodes_impl.nim
+++ b/nimbus/vm/interpreter/opcodes_impl.nim
@@ -384,6 +384,10 @@ op gasLimit, inline = true:
   ## 0x45, Get the block's gas limit
   push: c.getGasLimit()
 
+op baseFee, inline = true:
+  ## 0x45, Get the block's gas limit
+  push: c.getBaseFee()
+
 op chainId, inline = true:
   ## 0x46, Get current chain’s EIP-155 unique identifier.
   push: c.getChainId()
diff --git a/nimbus/vm/interpreter_dispatch.nim b/nimbus/vm/interpreter_dispatch.nim
index 7f8ab2312..ad818e789 100644
--- a/nimbus/vm/interpreter_dispatch.nim
+++ b/nimbus/vm/interpreter_dispatch.nim
@@ -251,6 +251,7 @@ let BerlinOpDispatch {.compileTime.}: array[Op, NimNode] = genBerlinJumpTable(Is
 proc genLondonJumpTable(ops: array[Op, NimNode]): array[Op, NimNode] {.compileTime.} =
   result = ops
   # incoming EIP-3198 and EIP-3529
+  result[BaseFee] = newIdentNode "baseFee"
 
 let LondonOpDispatch {.compileTime.}: array[Op, NimNode] = genLondonJumpTable(BerlinOpDispatch)
 
diff --git a/nimbus/vm/state.nim b/nimbus/vm/state.nim
index 3bebca869..6d6f7a7e7 100644
--- a/nimbus/vm/state.nim
+++ b/nimbus/vm/state.nim
@@ -141,6 +141,9 @@ method difficulty*(vmState: BaseVMState): UInt256 {.base, gcsafe.} =
 method gasLimit*(vmState: BaseVMState): GasInt {.base, gcsafe.} =
   vmState.blockHeader.gasLimit
 
+method baseFee*(vmState: BaseVMState): Uint256 {.base, gcsafe.} =
+  vmState.blockHeader.baseFee
+
 when defined(geth):
   import db/geth_db