void ttl74153_device::update()
{
int sel;
int section;
sel = (m_b << 1) | m_a;
/* process both sections */
for (section = 0; section < 2; section++)
{
if (m_enable[section])
m_output[section] = 0; // row 1 in truth table
else
m_output[section] = m_input_lines[section][sel];
}
/* call callback if either of the outputs changed */
if (!m_output_cb.isnull() &&
((m_output[0] != m_last_output[0]) || (m_output[1] != m_last_output[1])))
{
m_last_output[0] = m_output[0];
m_last_output[1] = m_output[1];
m_output_cb();
}
}
void mm5837_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
{
int tap_14 = BIT(m_shift, 13);
int tap_17 = BIT(m_shift, 16);
int zero = (m_shift == 0) ? 1 : 0;
m_shift <<= 1;
m_shift |= tap_14 ^ tap_17 ^ zero;
m_output_cb(BIT(m_shift, 16));
}
void ttl74148_device::update()
{
if (m_enable_input)
{
// row 1 in truth table
m_output = 0x07;
m_output_valid = 1;
m_enable_output = 1;
}
else
{
int bit0, bit1, bit2;
/* this comes straight off the data sheet schematics */
bit0 = !(((!m_input_lines[1]) &
m_input_lines[2] &
m_input_lines[4] &
m_input_lines[6]) |
((!m_input_lines[3]) &
m_input_lines[4] &
m_input_lines[6]) |
((!m_input_lines[5]) &
m_input_lines[6]) |
(!m_input_lines[7]));
bit1 = !(((!m_input_lines[2]) &
m_input_lines[4] &
m_input_lines[5]) |
((!m_input_lines[3]) &
m_input_lines[4] &
m_input_lines[5]) |
(!m_input_lines[6]) |
(!m_input_lines[7]));
bit2 = !((!m_input_lines[4]) |
(!m_input_lines[5]) |
(!m_input_lines[6]) |
(!m_input_lines[7]));
m_output = (bit2 << 2) | (bit1 << 1) | bit0;
m_output_valid = (m_input_lines[0] &
m_input_lines[1] &
m_input_lines[2] &
m_input_lines[3] &
m_input_lines[4] &
m_input_lines[5] &
m_input_lines[6] &
m_input_lines[7]);
m_enable_output = !m_output_valid;
}
/* call callback if any of the outputs changed */
if (!m_output_cb.isnull() &&
((m_output != m_last_output) ||
(m_output_valid != m_last_output_valid) || (m_enable_output != m_last_enable_output)))
{
m_last_output = m_output;
m_last_output_valid = m_output_valid;
m_last_enable_output = m_enable_output;
m_output_cb();
}
}
