xform_expr_basic.py

   1 # ScratchABlock - Program analysis and decompilation framework
   2 #
   3 # Copyright (c) 2020 Paul Sokolovsky
   4 #
   5 # This program is free software: you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License as published by
   7 # the Free Software Foundation, either version 3 of the License, or
   8 # (at your option) any later version.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License
  16 # along with this program. If not, see <http://www.gnu.org/licenses/>.
  17
  18 from core import *
  19
  20
  21 def expr_neg_if_possible(expr):
  22     if is_value(expr):
  23         return VALUE(-expr.val, expr.base)
  24     if is_expr(expr):
  25         if expr.op == "NEG":
  26             return expr.args[0]
  27         if expr.op == "+":
  28             new_args = [expr_neg(x) for x in expr.args]
  29             return EXPR("+", new_args)
  30
  31
  32 def expr_neg(expr):
  33     new = expr_neg_if_possible(expr)
  34     if new:
  35         return new
  36
  37     return EXPR("NEG", expr)