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// license:BSD-3-Clause
// copyright-holders:Ryan Holtz
/*
* nld_7485.cpp
*
* FIXME: Truthtable candidate
*
* DM7485: 4-bit Magnitude Comparators
*
* +------------+
* B3 |1 ++ 16| VCC
* LTIN |2 15| A3
* EQIN |3 14| B2
* GTIN |4 7485 13| A2
* GTOUT |5 12| A1
* EQOUT |6 11| B1
* LTOUT |7 10| A0
* GND |8 9| B0
* +------------+
*
* Naming convention attempts to follow Texas Instruments datasheet
*
*/
#include "nld_7485.h"
#include "nl_base.h"
namespace netlist
{
namespace devices
{
NETLIB_OBJECT(7485)
{
NETLIB_CONSTRUCTOR(7485)
, m_A(*this, {"A0", "A1", "A2", "A3"}, NETLIB_DELEGATE(inputs))
, m_B(*this, {"B0", "B1", "B2", "B3"}, NETLIB_DELEGATE(inputs))
, m_LTIN(*this, "LTIN", NETLIB_DELEGATE(inputs))
, m_EQIN(*this, "EQIN", NETLIB_DELEGATE(inputs))
, m_GTIN(*this, "GTIN", NETLIB_DELEGATE(inputs))
, m_LTOUT(*this, "LTOUT")
, m_EQOUT(*this, "EQOUT")
, m_GTOUT(*this, "GTOUT")
, m_power_pins(*this)
{
}
private:
// FIXME: Timing
NETLIB_HANDLERI(inputs)
{
for (std::size_t i = 4; i-- > 0; )
{
if (m_A[i]() > m_B[i]())
{
update_outputs(1, 0, 0);
return;
}
if (m_A[i]() < m_B[i]())
{
update_outputs(0, 1, 0);
return;
}
}
// must be == if we got here
if (m_EQIN())
update_outputs(0, 0, 1);
else if (m_GTIN() && m_LTIN())
update_outputs(0, 0, 0);
else if (m_GTIN())
update_outputs(1, 0, 0);
else if (m_LTIN())
update_outputs(0, 1, 0);
else
update_outputs(1, 1, 0);
}
void update_outputs(unsigned gt, unsigned lt, unsigned eq)
{
m_GTOUT.push(gt, NLTIME_FROM_NS(23));
m_LTOUT.push(lt, NLTIME_FROM_NS(23));
m_EQOUT.push(eq, NLTIME_FROM_NS(23));
}
object_array_t<logic_input_t, 4> m_A;
object_array_t<logic_input_t, 4> m_B;
logic_input_t m_LTIN;
logic_input_t m_EQIN;
logic_input_t m_GTIN;
logic_output_t m_LTOUT;
logic_output_t m_EQOUT;
logic_output_t m_GTOUT;
nld_power_pins m_power_pins;
};
NETLIB_DEVICE_IMPL(7485, "TTL_7485", "+A0,+A1,+A2,+A3,+B0,+B1,+B2,+B3,+LTIN,+EQIN,+GTIN,@VCC,@GND")
} //namespace devices
} // namespace netlist
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