nimbus-eth1/nimbus/evm/interpreter/utils/macros_gen_opcodes.nim

58 lines
1.6 KiB
Nim

# Nimbus
# Copyright (c) 2018 Status Research & Development GmbH
# Licensed under either of
# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
# * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
# at your option. This file may not be copied, modified, or distributed except according to those terms.
# ##################################################################
# Macros to facilitate opcode enum and table creation
import macros
macro fill_enum_table_holes*(enumTy: typedesc[enum], nop_filler, body: untyped): untyped =
## Fill the holes of table mapping for enum with a default value
##
## For example for enum
## type Foo = enum
## A = 0x00,
## B = 0x01,
## C = 0x02
## let foo = fill_enum_table_holes(Foo, 999):
## [A: 10, C: 20]
##
## will result into `[A: 10, B: 999, C: 20]`
# Sanity checks - body
# StmtList
# Bracket
# ExprColonExpr
# Ident "Stop"
# Command
# Ident "fixed"
# Ident "GasZero"
# ExprColonExpr
# Ident "Add"
# Command
# Ident "fixed"
# Ident "GasVeryLow"
body[0].expectKind(nnkBracket)
let
enumImpl = enumTy.getType[1]
opctable = body[0]
result = nnkBracket.newTree()
var
opcode = 1 # enumImpl[0] is an empty node
body_idx = 0
while opcode < enumImpl.len:
opctable[body_idx].expectKind(nnkExprColonExpr)
if eqIdent(enumImpl[opcode], opctable[body_idx][0]):
result.add opctable[body_idx]
inc body_idx
else:
result.add nop_filler
inc opcode