diff options
| -rw-r--r-- | miasm2/arch/x86/sem.py | 47 |
1 files changed, 37 insertions, 10 deletions
diff --git a/miasm2/arch/x86/sem.py b/miasm2/arch/x86/sem.py index 597f19df..9b961de8 100644 --- a/miasm2/arch/x86/sem.py +++ b/miasm2/arch/x86/sem.py @@ -415,6 +415,42 @@ def get_shift(a, b): shift = expr_simp(shift) return shift +def _rotate_tpl(ir, instr, a, b, op, op_cf=None): + """Template for generate rotater with operation @op + A temporary basic block is generated to handle 0-rotate + @op: operation to execute + @op_cf (optional): operation to use for carry flag. If not set, use @op + """ + if op_cf is None: + op_cf = op + + shifter = get_shift(a, b) + res = m2_expr.ExprOp(op, a, shifter, cf.zeroExtend(a.size)) + new_cf = m2_expr.ExprOp(op_cf, a, shifter, cf.zeroExtend(a.size))[:1] + + # Build basic blocks + e_do = [ + m2_expr.ExprAff(cf, new_cf), + # hack (only valid if b=1) + m2_expr.ExprAff(of, res.msb() ^ new_cf), + m2_expr.ExprAff(a, res), + ] + + # Don't generate conditional shifter on constant + if isinstance(shifter, m2_expr.ExprInt): + if int(shifter.arg) != 0: + return e_do, [] + else: + return [], [] + + e = [] + lbl_do = m2_expr.ExprId(ir.gen_label(), instr.mode) + lbl_skip = m2_expr.ExprId(ir.get_next_label(instr), instr.mode) + e_do.append(m2_expr.ExprAff(ir.IRDst, lbl_skip)) + e.append(m2_expr.ExprAff(ir.IRDst, m2_expr.ExprCond(shifter, lbl_do, + lbl_skip))) + return e, [irbloc(lbl_do.name, [e_do])] + def l_rol(ir, instr, a, b): e = [] @@ -442,16 +478,7 @@ def l_ror(ir, instr, a, b): def rcl(ir, instr, a, b): - e = [] - shifter = get_shift(a, b) - c = m2_expr.ExprOp('<<<c_rez', a, shifter, cf.zeroExtend(a.size)) - new_cf = m2_expr.ExprOp('<<<c_cf', a, shifter, cf.zeroExtend(a.size))[:1] - - e.append(m2_expr.ExprAff(cf, new_cf)) - # hack (only valid if b=1) - e.append(m2_expr.ExprAff(of, c.msb() ^ new_cf)) - e.append(m2_expr.ExprAff(a, c)) - return e, [] + return _rotate_tpl(ir, instr, a, b, '<<<c_rez', '<<<c_cf') def rcr(ir, instr, a, b): |