Gas & Memory ops refactoring - uses native integer instead of uint256 f…

…ixes #35 and #39 (#40)

* Gas refactoring - uses int64

* Use primitive int in test_vm_json

src/computation.nim

@@ -6,7 +6,7 @@
 # at your option. This file may not be copied, modified, or distributed except according to those terms.
 
 import
- strformat, strutils, sequtils, tables, macros, stint, terminal,
+ strformat, strutils, sequtils, tables, macros, stint, terminal, math,
  constants, errors, utils/hexadecimal, utils_numeric, validation, vm_state, logging, opcode_values, types,
  vm / [code_stream, gas_meter, memory, message, stack],
 
@@ -15,7 +15,7 @@ import
  vm/forks/f20150730_frontier/frontier_vm_state,
  vm/forks/f20161018_tangerine_whistle/tangerine_vm_state
 
-proc memoryGasCost*(sizeInBytes: UInt256): UInt256 =
+proc memoryGasCost*(sizeInBytes: Natural): GasInt =
  let
  sizeInWords = ceil32(sizeInBytes) div 32
  linearCost = sizeInWords * GAS_MEMORY
@@ -86,7 +86,7 @@ method shouldEraseReturnData*(c: BaseComputation): bool =
 
 method prepareChildMessage*(
  c: var BaseComputation,
- gas: UInt256,
+ gas: GasInt,
  to: string,
  value: UInt256,
  data: seq[byte],
@@ -105,13 +105,10 @@ method prepareChildMessage*(
  code,
  childOptions)
 
-method extendMemory*(c: var BaseComputation, startPosition: UInt256, size: UInt256) =
+method extendMemory*(c: var BaseComputation, startPosition: Natural, size: Natural) =
  # Memory Management
- #
- # validate_uint256(start_position, title="Memory start position")
- # validate_uint256(size, title="Memory size")
 
- let beforeSize = ceil32(len(c.memory).u256)
+ let beforeSize = ceil32(len(c.memory))
  let afterSize = ceil32(startPosition + size)
 
  let beforeCost = memoryGasCost(beforeSize)
@@ -201,21 +198,21 @@ method getLogEntries*(c: BaseComputation): seq[(string, seq[UInt256], string)] =
  else:
  result = @[]
 
-method getGasRefund*(c: BaseComputation): UInt256 =
+method getGasRefund*(c: BaseComputation): GasInt =
  if c.isError:
- result = 0.u256
+ result = 0
  else:
- result = c.gasMeter.gasRefunded + c.children.mapIt(it.getGasRefund()).foldl(a + b, 0.u256)
+ result = c.gasMeter.gasRefunded + c.children.mapIt(it.getGasRefund()).foldl(a + b, 0'i64)
 
-method getGasUsed*(c: BaseComputation): UInt256 =
+method getGasUsed*(c: BaseComputation): GasInt =
  if c.shouldBurnGas:
  result = c.msg.gas
  else:
- result = max(0.u256, c.msg.gas - c.gasMeter.gasRemaining)
+ result = max(0, c.msg.gas - c.gasMeter.gasRemaining)
 
-method getGasRemaining*(c: BaseComputation): UInt256 =
+method getGasRemaining*(c: BaseComputation): GasInt =
  if c.shouldBurnGas:
- result = 0.u256
+ result = 0
  else:
  result = c.gasMeter.gasRemaining
 

src/constants.nim

@@ -46,13 +46,13 @@ proc `==`*(a: UInt256, b: int): bool =
 proc `!=`*(a: UInt256, b: int): bool =
  a != b.u256
 
-proc `^`*(base: int; exp: int): UInt256 =
- let base = base.u256
- var ex = exp
- result = 1.u256
- while ex > 0:
- result = result * base
- dec(ex)
+# proc `^`*(base: int; exp: int): UInt256 =
+#  let base = base.u256
+#  var ex = exp
+#  result = 1.u256
+#  while ex > 0:
+#  result = result * base
+#  dec(ex)
 
 proc `^`*(left: Int256, right: int): Int256 =
  var value = right.i256
@@ -123,7 +123,7 @@ let
  INT_256_MAX_AS_UINT256* = cast[Uint256](high(Int256))
  NULLBYTE* = "\x00"
  EMPTYWORD* = repeat(NULLBYTE, 32)
- UINT160CEILING*: UInt256 = 2 ^ 160
+ UINT160CEILING*: UInt256 = 2.u256 ^ 160
  CREATE_CONTRACT_ADDRESS* = ""
  ZERO_ADDRESS* = repeat("\x00", 20)
  ZERO_HASH32* = repeat("\x00", 20)
@@ -147,34 +147,34 @@ let
  # GAS_SLOAD_COST* = 20.u256
  # GAS_SELF_DESTRUCT_COST* = 0.u256
  # GAS_IN_HANDLER* = 0.u256 # to be calculated in handler
- REFUND_SCLEAR* = 15_000.u256
+ REFUND_SCLEAR* = 15_000
 
  # GAS_SELF_DESTRUCT* = 0.u256
  # GAS_SELF_DESTRUCT_NEW_ACCOUNT* = 25_000.u256
  GAS_CREATE* = 32_000.u256
  # GAS_CALL* = 40.u256
- GAS_CALL_VALUE* = 9_000.u256
- GAS_CALL_STIPEND* = 2_300.u256
- GAS_NEW_ACCOUNT* = 25_000.u256
+ GAS_CALL_VALUE* = 9_000
+ GAS_CALL_STIPEND* = 2_300
+ GAS_NEW_ACCOUNT* = 25_000
 
  # GAS_COST_BALANCE* = 400.u256 # TODO: this is post-eip150, see also GAS_BALANCE
 
  # GAS_EXP* = 10.u256
  # GAS_EXP_BYTE* = 10.u256
- GAS_MEMORY* = 3.u256
+ GAS_MEMORY* = 3
  GAS_TX_CREATE* = 32_000.u256
  GAS_TX_DATA_ZERO* = 4.u256
  GAS_TX_DATA_NON_ZERO* = 68.u256
  GAS_TX* = 21_000.u256
  GAS_LOG* = 375.u256
- GAS_LOG_DATA* = 8.u256
- GAS_LOG_TOPIC* = 375.u256
+ GAS_LOG_DATA* = 8
+ GAS_LOG_TOPIC* = 375
  # GAS_SHA3* = 30.u256
- GAS_SHA3_WORD* = 6.u256
- GAS_COPY* = 3.u256
+ GAS_SHA3_WORD* = 6
+ GAS_COPY* = 3
  GAS_BLOCK_HASH* = 20.u256
  GAS_CODE_DEPOSIT* = 200.u256
- GAS_MEMORY_QUADRATIC_DENOMINATOR* = 512.u256
+ GAS_MEMORY_QUADRATIC_DENOMINATOR* = 512
  GAS_SHA256* = 60.u256
  GAS_SHA256WORD* = 12.u256
  GAS_RIP_EMD160* = 600.u256
@@ -188,7 +188,7 @@ let
  GAS_ECPAIRING_PER_POINT* = 80_000.u256
  GAS_LIMIT_EMA_DENOMINATOR* = 1_024.u256
  GAS_LIMIT_ADJUSTMENT_FACTOR* = 1_024.u256
- GAS_LIMIT_MAXIMUM*: UInt256 = 2 ^ 63 - 1.u256
+ GAS_LIMIT_MAXIMUM* =  high(int64)
  GAS_LIMIT_USAGE_ADJUSTMENT_NUMERATOR* = 3.u256
  GAS_LIMIT_USAGE_ADJUSTMENT_DENOMINATOR* = 2.u256
 
@@ -206,7 +206,7 @@ let
  MAX_UNCLE_DEPTH* = 6.u256
  MAX_UNCLES* = 2.u256
 
- SECPK1_P*: UInt256 = 2 ^ 256 - 2 ^ 32 - 977.u256
+ SECPK1_P*: UInt256 = 2.u256 ^ 256 - 2.u256 ^ 32 - 977.u256
  SECPK1_N*: UInt256 = "115792089237316195423570985008687907852837564279074904382605163141518161494337".u256
  SECPK1_A* = 0.u256
  SECPK1_B* = 7.u256

src/logic/arithmetic.nim

@@ -92,7 +92,7 @@ proc exp*(computation: var BaseComputation) =
 
  var gasCost = computation.gasCosts[GasExp]
  if not exponent.isZero:
- gasCost += gasCost * (one(Uint256) + log256(exponent))
+ gasCost += gasCost * (1 + log256(exponent))
  computation.gasMeter.consumeGas(gasCost, reason="EXP: exponent bytes")
 
  let res = if base.isZero: 0.u256 # 0^0 is 0 in py-evm

src/logic/call.nim

@@ -39,13 +39,13 @@ type
 using
  computation: var BaseComputation
 
-method msgExtraGas*(call: BaseCall, computation; gas: UInt256, to: string, value: UInt256): UInt256 {.base.} =
+method msgExtraGas*(call: BaseCall, computation; gas: GasInt, to: string, value: UInt256): GasInt {.base.} =
  raise newException(NotImplementedError, "Must be implemented by subclasses")
 
-method msgGas*(call: BaseCall, computation; gas: UInt256, to: string, value: UInt256): (UInt256, UInt256) {.base.} =
+method msgGas*(call: BaseCall, computation; gas: GasInt, to: string, value: UInt256): (GasInt, GasInt) {.base.} =
  let extraGas = call.msgExtraGas(computation, gas, to, value)
  let totalFee = gas + extraGas
- let childMsgGas = gas + (if value != 0: GAS_CALL_STIPEND else: 0.u256)
+ let childMsgGas = gas + (if value != 0: GAS_CALL_STIPEND else: 0)
  (childMsgGas, totalFee)
 
 method callParams*(call: BaseCall, computation): (UInt256, UInt256, string, string, string, UInt256, UInt256, UInt256, UInt256, bool, bool) {.base.} =
@@ -60,11 +60,13 @@ method runLogic*(call: BaseCall, computation) =
  shouldTransferValue,
  isStatic) = call.callParams(computation)
 
- computation.extendMemory(memoryInputStartPosition, memoryInputSize)
- computation.extendMemory(memoryOutputStartPosition, memoryOutputSize)
+ let (memInPos, memInLen, memOutPos, memOutLen) = (memoryInputStartPosition.toInt, memoryInputSize.toInt, memoryOutputStartPosition.toInt, memoryOutputSize.toInt)
 
- let callData = computation.memory.read(memoryInputStartPosition, memoryInputSize)
- let (childMsgGas, childMsgGasFee) = call.msgGas(computation, gas, to, value)
+ computation.extendMemory(memInPos, memInLen)
+ computation.extendMemory(memOutPos, memOutLen)
+
+ let callData = computation.memory.read(memInPos, memInLen)
+ let (childMsgGas, childMsgGasFee) = call.msgGas(computation, gas.toInt, to, value)
  computation.gasMeter.consumeGas(childMsgGasFee, reason = $call.kind)
 
  # TODO: Pre-call checks
@@ -116,22 +118,22 @@ method runLogic*(call: BaseCall, computation) =
  else:
  computation.stack.push(1.u256)
  if not childComputation.shouldEraseReturnData:
- let actualOutputSize = min(memoryOutputSize, childComputation.output.len.u256)
+ let actualOutputSize = min(memOutLen, childComputation.output.len)
  computation.memory.write(
- memoryOutputStartPosition,
+ memOutPos,
  actualOutputSize,
- childComputation.output.toBytes[0 ..< actualOutputSize.toInt])
+ childComputation.output.toBytes[0 ..< actualOutputSize])
  if not childComputation.shouldBurnGas:
  computation.gasMeter.returnGas(childComputation.gasMeter.gasRemaining)
 
-method msgExtraGas(call: Call, computation; gas: UInt256, to: string, value: UInt256): UInt256 =
+method msgExtraGas(call: Call, computation; gas: GasInt, to: string, value: UInt256): GasInt =
  # TODO: db
  # with computation.vm_state.state_db(read_only=True) as state_db:
  # let accountExists = db.accountExists(to)
  let accountExists = false
 
- let transferGasFee = if value != 0: GAS_CALL_VALUE else: 0.u256
- let createGasFee = if not accountExists: GAS_NEW_ACCOUNT else: 0.u256
+ let transferGasFee = if value != 0: GAS_CALL_VALUE else: 0
+ let createGasFee = if not accountExists: GAS_NEW_ACCOUNT else: 0
  transferGasFee + createGasFee
 
 method callParams(call: CallCode, computation): (UInt256, UInt256, string, string, string, UInt256, UInt256, UInt256, UInt256, bool, bool) =
@@ -154,8 +156,8 @@ method callParams(call: CallCode, computation): (UInt256, UInt256, string, strin
  true, # should_transfer_value,
  computation.msg.isStatic)
 
-method msgExtraGas(call: CallCode, computation; gas: UInt256, to: string, value: UInt256): UInt256 =
- if value != 0: GAS_CALL_VALUE else: 0.u256
+method msgExtraGas(call: CallCode, computation; gas: GasInt, to: string, value: UInt256): GasInt =
+ if value != 0: GAS_CALL_VALUE else: 0
 
 method callParams(call: Call, computation): (UInt256, UInt256, string, string, string, UInt256, UInt256, UInt256, UInt256, bool, bool) =
  let gas = computation.stack.popInt()
@@ -180,11 +182,11 @@ method callParams(call: Call, computation): (UInt256, UInt256, string, string, s
  true, # should_transfer_value,
  computation.msg.isStatic)
 
-method msgGas(call: DelegateCall, computation; gas: UInt256, to: string, value: UInt256): (UInt256, UInt256) =
+method msgGas(call: DelegateCall, computation; gas: GasInt, to: string, value: UInt256): (GasInt, GasInt) =
  (gas, gas)
 
-method msgExtraGas(call: DelegateCall, computation; gas: UInt256, to: string, value: UInt256): UInt256 =
- 0.u256
+method msgExtraGas(call: DelegateCall, computation; gas: GasInt, to: string, value: UInt256): GasInt =
+ 0
 
 method callParams(call: DelegateCall, computation): (UInt256, UInt256, string, string, string, UInt256, UInt256, UInt256, UInt256, bool, bool) =
  let gas = computation.stack.popInt()
@@ -209,39 +211,39 @@ method callParams(call: DelegateCall, computation): (UInt256, UInt256, string, s
  false, # should_transfer_value,
  computation.msg.isStatic)
 
-proc maxChildGasEIP150*(gas: UInt256): UInt256 =
+proc maxChildGasEIP150*(gas: GasInt): GasInt =
  gas - gas div 64
 
-proc computeEIP150MsgGas(computation; gas: UInt256, extraGas: UInt256, value: UInt256, name: string, callStipend: UInt256): (UInt256, UInt256) =
+proc computeEIP150MsgGas(computation; gas, extraGas: GasInt, value: UInt256, name: string, callStipend: GasInt): (GasInt, GasInt) =
  if computation.gasMeter.gasRemaining < extraGas:
  raise newException(OutOfGas, &"Out of gas: Needed {extraGas} - Remaining {computation.gasMeter.gasRemaining} - Reason: {name}")
  let gas = min(gas, maxChildGasEIP150(computation.gasMeter.gasRemaining - extraGas))
  let totalFee = gas + extraGas
- let childMsgGas = gas + (if value != 0: callStipend else: 0.u256)
+ let childMsgGas = gas + (if value != 0: callStipend else: 0)
  (childMsgGas, totalFee)
 
-method msgGas(call: CallEIP150, computation; gas: UInt256, to: string, value: UInt256): (UInt256, UInt256) =
+method msgGas(call: CallEIP150, computation; gas: GasInt, to: string, value: UInt256): (GasInt, GasInt) =
  let extraGas = call.msgExtraGas(computation, gas, to, value)
  computeEIP150MsgGas(computation, gas, extraGas, value, $call.kind, GAS_CALL_STIPEND)
 
-method msgGas(call: CallCodeEIP150, computation; gas: UInt256, to: string, value: UInt256): (UInt256, UInt256) =
+method msgGas(call: CallCodeEIP150, computation; gas: GasInt, to: string, value: UInt256): (GasInt, GasInt) =
  let extraGas = call.msgExtraGas(computation, gas, to, value)
  computeEIP150MsgGas(computation, gas, extraGas, value, $call.kind, GAS_CALL_STIPEND)
 
-method msgGas(call: DelegateCallEIP150, computation; gas: UInt256, to: string, value: UInt256): (UInt256, UInt256) =
+method msgGas(call: DelegateCallEIP150, computation; gas: GasInt, to: string, value: UInt256): (GasInt, GasInt) =
  let extraGas = call.msgExtraGas(computation, gas, to, value)
- computeEIP150MsgGas(computation, gas, extraGas, value, $call.kind, 0.u256)
+ computeEIP150MsgGas(computation, gas, extraGas, value, $call.kind, 0)
 
-proc msgExtraGas*(call: CallEIP161, computation; gas: UInt256, to: string, value: UInt256): UInt256 =
+proc msgExtraGas*(call: CallEIP161, computation; gas: GasInt, to: string, value: UInt256): GasInt =
  # TODO: with
  # with computation.vm_state.state_db(read_only=True) as state_db:
  # account_is_dead = (
  # not state_db.account_exists(to) or
  # state_db.account_is_empty(to))
  let accountIsDead = true
 
- let transferGasFee = if value != 0: GAS_CALL_VALUE else: 0.u256
- let createGasFee = if accountIsDead and value != 0: GAS_NEW_ACCOUNT else: 0.u256
+ let transferGasFee = if value != 0: GAS_CALL_VALUE else: 0
+ let createGasFee = if accountIsDead and value != 0: GAS_NEW_ACCOUNT else: 0
  transferGasFee + createGasFee
 
 

src/logic/context.nim

@@ -47,14 +47,15 @@ proc callDataCopy*(computation: var BaseComputation) =
  let (memStartPosition,
  calldataStartPosition,
  size) = computation.stack.popInt(3)
- computation.extendMemory(memStartPosition, size)
+ let (memPos, callPos, len) = (memStartPosition.toInt, calldataStartPosition.toInt, size.toInt)
+ computation.extendMemory(memPos, len)
 
- let wordCount = ceil32(size) div 32
+ let wordCount = ceil32(len) div 32
  let copyGasCost = wordCount * constants.GAS_COPY
  computation.gasMeter.consumeGas(copyGasCost, reason="CALLDATACOPY fee")
- let value = computation.msg.data[calldataStartPosition.toInt ..< (calldataStartPosition + size).toInt]
- let paddedValue = padRight(value, size.toInt, 0.byte)
- computation.memory.write(memStartPosition, size, paddedValue)
+ let value = computation.msg.data[callPos ..< callPos + len]
+ let paddedValue = padRight(value, len, 0.byte)
+ computation.memory.write(memPos, len, paddedValue)
 
 
 proc codesize*(computation: var BaseComputation) =
@@ -66,8 +67,10 @@ proc codecopy*(computation: var BaseComputation) =
  let (memStartPosition,
  codeStartPosition,
  size) = computation.stack.popInt(3)
- computation.extendMemory(memStartPosition, size)
- let wordCount = ceil32(size) div 32
+ let (memPos, codePos, len) = (memStartPosition.toInt, codeStartPosition.toInt, size.toInt)
+ computation.extendMemory(memPos, len)
+
+ let wordCount = ceil32(len) div 32
  let copyGasCost = constants.GAS_COPY * wordCount
 
  computation.gasMeter.consumeGas(copyGasCost, reason="CODECOPY: word gas cost")
@@ -79,7 +82,7 @@ proc codecopy*(computation: var BaseComputation) =
 
 
 proc gasprice*(computation: var BaseComputation) =
- computation.stack.push(computation.msg.gasPrice)
+ computation.stack.push(computation.msg.gasPrice.u256)
 
 
 proc extCodeSize*(computation: var BaseComputation) =
@@ -93,8 +96,9 @@ proc extCodeSize*(computation: var BaseComputation) =
 proc extCodeCopy*(computation: var BaseComputation) =
  let account = forceBytesToAddress(computation.stack.popString)
  let (memStartPosition, codeStartPosition, size) = computation.stack.popInt(3)
- computation.extendMemory(memStartPosition, size)
- let wordCount = ceil32(size) div 32
+ let (memPos, codePos, len) = (memStartPosition.toInt, codeStartPosition.toInt, size.toInt)
+ computation.extendMemory(memPos, len)
+ let wordCount = ceil32(len) div 32
  let copyGasCost = constants.GAS_COPY * wordCount
 
  computation.gasMeter.consumeGas(copyGasCost, reason="EXTCODECOPY: word gas cost")
@@ -112,15 +116,16 @@ proc returnDataSize*(computation: var BaseComputation) =
 
 proc returnDataCopy*(computation: var BaseComputation) =
  let (memStartPosition, returnDataStartPosition, size) = computation.stack.popInt(3)
- if returnDataStartPosition + size > computation.returnData.len:
+ let (memPos, returnPos, len) = (memStartPosition.toInt, returnDataStartPosition.toInt, size.toInt)
+ if returnPos + len > computation.returnData.len:
  raise newException(OutOfBoundsRead,
  "Return data length is not sufficient to satisfy request. Asked \n" &
  &"for data from index {returnDataStartPosition} to {returnDataStartPosition + size}. Return data is {computation.returnData.len} in \n" &
  "length")
 
- computation.extendMemory(memStartPosition, size)
- let wordCount = ceil32(size) div 32
+ computation.extendMemory(memPos, len)
+ let wordCount = ceil32(len) div 32
  let copyGasCost = wordCount * constants.GAS_COPY
  computation.gasMeter.consumeGas(copyGasCost, reason="RETURNDATACOPY fee")
- let value = ($computation.returnData)[returnDataStartPosition.toInt ..< (returnDataStartPosition + size).toInt]
- computation.memory.write(memStartPosition, size, value)
+ let value = ($computation.returnData)[returnPos ..< returnPos + len]
+ computation.memory.write(memPos, len, value)

src/logic/flow.nim

@@ -55,4 +55,4 @@ proc pc*(computation) =
 
 proc gas*(computation) =
  let gasRemaining = gasMeter.gasRemaining
- stack.push(gasRemaining)
+ stack.push(gasRemaining.u256)