// license:BSD-3-Clause // copyright-holders:Curt Coder, hap /********************************************************************** PLA (Programmable Logic Array) emulation **********************************************************************/ #include "pla.h" #include "jedparse.h" #include "plaparse.h" const device_type PLA = &device_creator; //------------------------------------------------- // pla_device - constructor //------------------------------------------------- pla_device::pla_device(const machine_config &mconfig, std::string tag, device_t *owner, UINT32 clock) : device_t(mconfig, PLA, "PLA", tag, owner, clock, "pla", __FILE__), m_format(PLA_FMT_JEDBIN), m_inputs(0), m_outputs(0), m_terms(0), m_input_mask(0), m_xor(0), m_cache_size(0), m_cache2_ptr(0) { } //------------------------------------------------- // device_start - device-specific startup //------------------------------------------------- void pla_device::device_start() { assert(region() != nullptr); assert(m_terms < MAX_TERMS); assert(m_inputs < 32 && m_outputs <= 32); if (m_input_mask == 0) m_input_mask = ((UINT64)1 << m_inputs) - 1; m_input_mask = ((UINT64)m_input_mask << 32) | m_input_mask; // parse fusemap parse_fusemap(); // initialize cache m_cache2_ptr = 0; for (auto & elem : m_cache2) elem = 0x80000000; m_cache_size = 0; int csize = 1 << ((m_inputs > MAX_CACHE_BITS) ? MAX_CACHE_BITS : m_inputs); m_cache.resize(csize); for (int i = 0; i < csize; i++) m_cache[i] = read(i); m_cache_size = csize; } //------------------------------------------------- // parse_fusemap - //------------------------------------------------- void pla_device::parse_fusemap() { jed_data jed; int result = JEDERR_NONE; // read pla file switch (m_format) { case PLA_FMT_JEDBIN: result = jedbin_parse(region()->base(), region()->bytes(), &jed); break; case PLA_FMT_BERKELEY: result = pla_parse(region()->base(), region()->bytes(), &jed); break; } if (result != JEDERR_NONE) { for (int p = 0; p < m_terms; p++) { m_term[p].and_mask = 0; m_term[p].or_mask = 0; } logerror("%s PLA parse error %d!\n", tag().c_str(), result); return; } // parse it UINT32 fusenum = 0; for (int p = 0; p < m_terms; p++) { term *term = &m_term[p]; // AND mask term->and_mask = 0; for (int i = 0; i < m_inputs; i++) { // complement term->and_mask |= (UINT64)jed_get_fuse(&jed, fusenum++) << (i + 32); // true term->and_mask |= (UINT64)jed_get_fuse(&jed, fusenum++) << i; } // OR mask term->or_mask = 0; for (int f = 0; f < m_outputs; f++) { term->or_mask |= !jed_get_fuse(&jed, fusenum++) << f; } term->or_mask <<= 32; } // XOR mask m_xor = 0; for (int f = 0; f < m_outputs; f++) { m_xor |= jed_get_fuse(&jed, fusenum++) << f; } m_xor <<= 32; } //------------------------------------------------- // read - //------------------------------------------------- UINT32 pla_device::read(UINT32 input) { // try the cache first if (input < m_cache_size) return m_cache[input]; for (auto cache2_entry : m_cache2) { if ((UINT32)cache2_entry == input) { // cache2 hit return cache2_entry >> 32; } } // cache miss, process terms UINT64 inputs = ((~(UINT64)input << 32) | input) & m_input_mask; UINT64 s = 0; for (int i = 0; i < m_terms; ++i) { term* term = &m_term[i]; if ((term->and_mask | inputs) == m_input_mask) { s |= term->or_mask; } } s ^= m_xor; // store output in cache2 m_cache2[m_cache2_ptr] = s | input; ++m_cache2_ptr &= (CACHE2_SIZE - 1); return s >> 32; }