yosys/passes/opt/opt_mem_widen.cc

108 lines
3.6 KiB
C++

/*
* yosys -- Yosys Open SYnthesis Suite
*
* Copyright (C) 2021 Marcelina Kościelnicka <mwk@0x04.net>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
*/
#include "kernel/yosys.h"
#include "kernel/mem.h"
USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN
struct OptMemWidenPass : public Pass {
OptMemWidenPass() : Pass("opt_mem_widen", "optimize memories where all ports are wide") { }
void help() override
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" opt_mem_widen [options] [selection]\n");
log("\n");
log("This pass looks for memories where all ports are wide and adjusts the base\n");
log("memory width up until that stops being the case.\n");
log("\n");
}
void execute(std::vector<std::string> args, RTLIL::Design *design) override
{
log_header(design, "Executing OPT_MEM_WIDEN pass (optimize memories where all ports are wide).\n");
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++) {
// if (args[argidx] == "-nomux") {
// mode_nomux = true;
// continue;
// }
break;
}
extra_args(args, argidx, design);
int total_count = 0;
for (auto module : design->selected_modules()) {
for (auto &mem : Mem::get_selected_memories(module)) {
// If the memory has no read ports, opt_clean will remove it
// instead.
if (mem.rd_ports.empty())
continue;
int factor_log2 = mem.rd_ports[0].wide_log2;
for (auto &port : mem.rd_ports)
if (port.wide_log2 < factor_log2)
factor_log2 = port.wide_log2;
for (auto &port : mem.wr_ports)
if (port.wide_log2 < factor_log2)
factor_log2 = port.wide_log2;
if (factor_log2 == 0)
continue;
log("Widening base width of memory %s in module %s by factor %d.\n", log_id(mem.memid), log_id(module->name), 1 << factor_log2);
total_count++;
// The inits are too messy to expand one-by-one, for they may
// collide with one another after expansion. Just hit it with
// a hammer.
bool has_init = !mem.inits.empty();
Const init_data;
if (has_init) {
init_data = mem.get_init_data();
mem.clear_inits();
}
mem.width <<= factor_log2;
mem.size >>= factor_log2;
mem.start_offset >>= factor_log2;
if (has_init) {
MemInit new_init;
new_init.addr = mem.start_offset;
new_init.data = init_data;
new_init.en = Const(State::S1, mem.width);
mem.inits.push_back(new_init);
}
for (auto &port : mem.rd_ports) {
port.wide_log2 -= factor_log2;
port.addr = port.addr.extract_end(factor_log2);
}
for (auto &port : mem.wr_ports) {
port.wide_log2 -= factor_log2;
port.addr = port.addr.extract_end(factor_log2);
}
mem.emit();
}
}
if (total_count)
design->scratchpad_set_bool("opt.did_something", true);
log("Performed a total of %d transformations.\n", total_count);
}
} OptMemWidenPass;
PRIVATE_NAMESPACE_END