diff --git a/nimbus/vm/computation.nim b/nimbus/vm/computation.nim
index 73eee2ae2..a972104bb 100644
--- a/nimbus/vm/computation.nim
+++ b/nimbus/vm/computation.nim
@@ -17,6 +17,64 @@ import
 logScope:
   topics = "vm computation"
 
+const
+  evmc_enabled* {.booldefine.} = true
+
+template getCoinbase*(c: Computation): EthAddress =
+  when evmc_enabled:
+    fromEvmc c.host.getTxContext().block_coinbase
+  else:
+    c.vmState.coinbase
+
+template getTimestamp*(c: Computation): int64 =
+  when evmc_enabled:
+    c.host.getTxContext().block_timestamp
+  else:
+    c.vmState.timestamp.toUnix
+
+template getBlockNumber*(c: Computation): Uint256 =
+  when evmc_enabled:
+    c.host.getTxContext().block_number.u256
+  else:
+    c.vmState.blockNumber.blockNumberToVmWord
+
+template getDifficulty*(c: Computation): DifficultyInt =
+  when evmc_enabled:
+    Uint256.fromEvmc c.host.getTxContext().block_difficulty
+  else:
+    c.vmState.difficulty
+
+template getGasLimit*(c: Computation): GasInt =
+  when evmc_enabled:
+    c.host.getTxContext().block_gas_limit.GasInt
+  else:
+    c.vmState.gasLimit
+
+template getChainId*(c: Computation): uint =
+  when evmc_enabled:
+    Uint256.fromEvmc(c.host.getTxContext().chain_id).truncate(uint)
+  else:
+    c.vmState.chaindb.config.chainId
+
+template getOrigin*(c: Computation): EthAddress =
+  when evmc_enabled:
+    fromEvmc c.host.getTxContext().tx_origin
+  else:
+    c.vmState.txOrigin
+
+template getGasPrice*(c: Computation): GasInt =
+  when evmc_enabled:
+    Uint256.fromEvmc(c.host.getTxContext().tx_gas_price).truncate(GasInt)
+  else:
+    c.vmState.txGasPrice
+
+template getBlockHash*(c: Computation, blockNumber: Uint256): Hash256 =
+  #when evmc_enabled:
+  #  c.host.getBlockHash(blockNumber.truncate(int64))
+  #else:
+    #randomStatetest7.json
+    c.vmState.getAncestorHash(blockNumber.vmWordToBlockNumber)
+
 proc newComputation*(vmState: BaseVMState, message: Message): Computation =
   new result
   result.vmState = vmState
@@ -27,6 +85,13 @@ proc newComputation*(vmState: BaseVMState, message: Message): Computation =
   result.touchedAccounts = initHashSet[EthAddress]()
   result.suicides = initHashSet[EthAddress]()
   result.code = newCodeStream(message.code)
+
+  when evmc_enabled:
+    result.host.init(
+      nim_host_get_interface(),
+      cast[evmc_host_context](result)
+    )
+
   # a dummy/terminus continuation proc
   result.nextProc = proc() =
     discard
diff --git a/nimbus/vm/evmc_api.nim b/nimbus/vm/evmc_api.nim
index 6adabf59b..f11fda4c6 100644
--- a/nimbus/vm/evmc_api.nim
+++ b/nimbus/vm/evmc_api.nim
@@ -7,14 +7,14 @@
 
 import evmc/evmc, evmc_helpers, eth/common
 
-proc nim_host_get_interface(): ptr evmc_host_interface {.importc, cdecl.}
-proc nim_host_create_context(vmstate: pointer, msg: ptr evmc_message): evmc_host_context {.importc, cdecl.}
-proc nim_host_destroy_context(ctx: evmc_host_context) {.importc, cdecl.}
-proc nim_create_nimbus_vm(): ptr evmc_vm {.importc, cdecl.}
+proc nim_host_get_interface*(): ptr evmc_host_interface {.importc, cdecl.}
+proc nim_host_create_context*(vmstate: pointer, msg: ptr evmc_message): evmc_host_context {.importc, cdecl.}
+proc nim_host_destroy_context*(ctx: evmc_host_context) {.importc, cdecl.}
+proc nim_create_nimbus_vm*(): ptr evmc_vm {.importc, cdecl.}
 
 type
   HostContext* = object
-    host: ptr evmc_host_interface
+    host*: ptr evmc_host_interface
     context*: evmc_host_context
 
 proc init*(x: var HostContext, host: ptr evmc_host_interface, context: evmc_host_context) =
@@ -25,10 +25,12 @@ proc init*(x: typedesc[HostContext], host: ptr evmc_host_interface, context: evm
   result.init(host, context)
 
 proc getTxContext*(ctx: HostContext): evmc_tx_context =
-  ctx.host.get_tx_context(ctx.context)
+  {.gcsafe.}:
+    ctx.host.get_tx_context(ctx.context)
 
 proc getBlockHash*(ctx: HostContext, number: int64): Hash256 =
-  Hash256.fromEvmc ctx.host.get_block_hash(ctx.context, number)
+  {.gcsafe.}:
+    Hash256.fromEvmc ctx.host.get_block_hash(ctx.context, number)
 
 proc accountExists*(ctx: HostContext, address: EthAddress): bool =
   var address = toEvmc(address)
diff --git a/nimbus/vm/interpreter/opcodes_impl.nim b/nimbus/vm/interpreter/opcodes_impl.nim
index ed19dc8c4..d5c753323 100644
--- a/nimbus/vm/interpreter/opcodes_impl.nim
+++ b/nimbus/vm/interpreter/opcodes_impl.nim
@@ -12,7 +12,7 @@ import
   ./gas_meter, ./gas_costs, ./opcode_values, ./vm_forks,
   ../memory, ../message, ../stack, ../code_stream, ../computation,
   ../../vm_state, ../../errors, ../../constants, ../../vm_types,
-  ../../db/[db_chain, state_db], ../../utils
+  ../../db/[db_chain, state_db], ../../utils, ../evmc_api, ../evmc_helpers
 
 logScope:
   topics = "opcode impl"
@@ -240,7 +240,7 @@ op balance, inline = true:
 
 op origin, inline = true:
   ## 0x32, Get execution origination address.
-  push: c.vmState.txOrigin
+  push: c.getOrigin()
 
 op caller, inline = true:
   ## 0x33, Get caller address.
@@ -301,7 +301,7 @@ op codeCopy, inline = false, memStartPos, copyStartPos, size:
 
 op gasprice, inline = true:
   ## 0x3A, Get price of gas in current environment.
-  push: c.vmState.txGasPrice
+  push: c.getGasPrice()
 
 op extCodeSize, inline = true:
   ## 0x3b, Get size of an account's code
@@ -350,32 +350,31 @@ op returnDataCopy, inline = false,  memStartPos, copyStartPos, size:
 
 op blockhash, inline = true, blockNumber:
   ## 0x40, Get the hash of one of the 256 most recent complete blocks.
-  push: c.vmState.getAncestorHash(blockNumber.vmWordToBlockNumber)
+  push: c.getBlockHash(blockNumber)
 
 op coinbase, inline = true:
   ## 0x41, Get the block's beneficiary address.
-  push: c.vmState.coinbase
+  push: c.getCoinbase()
 
 op timestamp, inline = true:
   ## 0x42, Get the block's timestamp.
-  push: c.vmState.timestamp.toUnix
+  push: c.getTimestamp()
 
 op blocknumber, inline = true:
   ## 0x43, Get the block's number.
-  push: c.vmState.blockNumber.blockNumberToVmWord
+  push: c.getBlockNumber()
 
 op difficulty, inline = true:
   ## 0x44, Get the block's difficulty
-  push: c.vmState.difficulty
+  push: c.getDifficulty()
 
 op gasLimit, inline = true:
   ## 0x45, Get the block's gas limit
-  push: c.vmState.gasLimit
+  push: c.getGasLimit()
 
 op chainId, inline = true:
   ## 0x46, Get current chain’s EIP-155 unique identifier.
-  # TODO: this is a stub
-  push: c.vmState.chaindb.config.chainId
+  push: c.getChainId()
 
 op selfBalance, inline = true:
   ## 0x47, Get current contract's balance.
diff --git a/nimbus/vm_types.nim b/nimbus/vm_types.nim
index dbb6c6066..d9a82e1b7 100644
--- a/nimbus/vm_types.nim
+++ b/nimbus/vm_types.nim
@@ -8,7 +8,7 @@
 import
   tables, eth/common, eth/trie/db,
   options, json, sets,
-  ./vm/[memory, stack, code_stream],
+  ./vm/[memory, stack, code_stream, evmc_api],
   ./vm/interpreter/[gas_costs, opcode_values, vm_forks], # TODO - will be hidden at a lower layer
   ./db/[db_chain, state_db]
 
@@ -59,6 +59,7 @@ type
   Computation* = ref object
     # The execution computation
     vmState*:               BaseVMState
+    host*:                  HostContext
     msg*:                   Message
     memory*:                Memory
     stack*:                 Stack