diff options
Diffstat (limited to 'miasm2/expression/simplifications_common.py')
| -rw-r--r-- | miasm2/expression/simplifications_common.py | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/miasm2/expression/simplifications_common.py b/miasm2/expression/simplifications_common.py index 82f2cf75..d89b7518 100644 --- a/miasm2/expression/simplifications_common.py +++ b/miasm2/expression/simplifications_common.py @@ -477,6 +477,21 @@ def simp_slice(e_s, e): args = [e_s.expr_simp_wrapper(a[e.start:e.stop]) for a in e.arg.args] e = ExprOp(e.arg.op, *args) + # (a >> int)[x:y] => a[x+int:y+int] with int+y <= a.size + # (a << int)[x:y] => a[x-int:y-int] with x-int >= 0 + elif (isinstance(e.arg, ExprOp) and e.arg.op in [">>", "<<"] and + isinstance(e.arg.args[1], ExprInt)): + arg, shift = e.arg.args + shift = int(shift.arg) + if e.arg.op == ">>": + if shift + e.stop <= arg.size: + return arg[e.start + shift:e.stop + shift] + elif e.arg.op == "<<": + if e.start - shift >= 0: + return arg[e.start - shift:e.stop - shift] + else: + raise ValueError('Bad case') + return e |