diff options
-rw-r--r-- | src/emu/machine/z8536.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/src/emu/machine/z8536.c b/src/emu/machine/z8536.c index c1393b2988d..a497f3aefc4 100644 --- a/src/emu/machine/z8536.c +++ b/src/emu/machine/z8536.c @@ -828,6 +828,7 @@ void z8536_device::external_port_w(int port, int bit, int state) case PORT_A: case PORT_B: { + assert((PORT_A_DATA_DIRECTION + (port << 3)) >= 0 && (PORT_A_DATA_DIRECTION + (port << 3)) < ARRAY_LENGTH(m_register)); UINT8 ddr = m_register[PORT_A_DATA_DIRECTION + (port << 3)]; if (!BIT(ddr, bit)) return; |