diff options
Diffstat (limited to 'miasm/expression')
| -rw-r--r-- | miasm/expression/simplifications.py | 2 | ||||
| -rw-r--r-- | miasm/expression/simplifications_common.py | 22 |
2 files changed, 22 insertions, 2 deletions
diff --git a/miasm/expression/simplifications.py b/miasm/expression/simplifications.py index 585a9c6b..8f63ab91 100644 --- a/miasm/expression/simplifications.py +++ b/miasm/expression/simplifications.py @@ -58,7 +58,7 @@ class ExpressionSimplifier(object): simplifications_common.simp_test_signext_inf, simplifications_common.simp_test_zeroext_inf, simplifications_common.simp_cond_inf_eq_unsigned_zero, - + simplifications_common.simp_compose_and_mask, ], m2_expr.ExprSlice: [ diff --git a/miasm/expression/simplifications_common.py b/miasm/expression/simplifications_common.py index cda9c5e2..ddd21a63 100644 --- a/miasm/expression/simplifications_common.py +++ b/miasm/expression/simplifications_common.py @@ -607,7 +607,6 @@ def simp_compose(e_s, expr): return ExprCond(cond, arg1, arg2) return ExprCompose(*args) - def simp_cond(_, expr): """ Common simplifications on ExprCond. @@ -1554,3 +1553,24 @@ def simp_add_multiple(_, expr): if len(out) == 1: return out[0] return ExprOp('+', *out) + +def simp_compose_and_mask(_, expr): + """ + {X 0 8, Y 8 16} & 0xFF => X + {X 0 32} & 0xFFFF => X[0:16] + {X 0 8, Y 8 24, Z 24 32} & 0xFFFFFF => X|Y + """ + if not expr.is_op('&'): + return expr + # handle the case where arg2 = arg1.mask + if len(expr.args) != 2: + return expr + arg1, arg2 = expr.args + if not arg1.is_compose(): + return expr + if not arg2.is_int(): + return expr + for i in range(8, arg1.size, 8): + if arg2.arg == ExprInt(0, i).mask.arg: + return ExprSlice(arg1, 0, i) + return expr |