From 3c643c57dfee9956697e8629a746bc04439be5a2 Mon Sep 17 00:00:00 2001
From: whitequark <whitequark@whitequark.org>
Date: Fri, 15 Nov 2019 03:11:46 +0000
Subject: [PATCH] write_verilog: add -extmem option, to write split memory init
files.
Some toolchains (in particular Quartus) are pathologically slow if
a large amount of assignments in `initial` blocks are used.
---
backends/verilog/verilog_backend.cc | 90 +++++++++++++++++++++++++----
1 file changed, 80 insertions(+), 10 deletions(-)
diff --git a/backends/verilog/verilog_backend.cc b/backends/verilog/verilog_backend.cc
index 24e397bda..54d0f6148 100644
--- a/backends/verilog/verilog_backend.cc
+++ b/backends/verilog/verilog_backend.cc
@@ -33,11 +33,11 @@
USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN
-bool verbose, norename, noattr, attr2comment, noexpr, nodec, nohex, nostr, defparam, decimal, siminit;
-int auto_name_counter, auto_name_offset, auto_name_digits;
+bool verbose, norename, noattr, attr2comment, noexpr, nodec, nohex, nostr, extmem, defparam, decimal, siminit;
+int auto_name_counter, auto_name_offset, auto_name_digits, extmem_counter;
std::map<RTLIL::IdString, int> auto_name_map;
std::set<RTLIL::IdString> reg_wires, reg_ct;
-std::string auto_prefix;
+std::string auto_prefix, extmem_prefix;
RTLIL::Module *active_module;
dict<RTLIL::SigBit, RTLIL::State> active_initdata;
@@ -1069,14 +1069,64 @@ bool dump_cell_expr(std::ostream &f, std::string indent, RTLIL::Cell *cell)
f << stringf("%s" "reg [%d:%d] %s [%d:%d];\n", indent.c_str(), width-1, 0, mem_id.c_str(), size+offset-1, offset);
if (use_init)
{
- f << stringf("%s" "initial begin\n", indent.c_str());
- for (int i=0; i<size; i++)
+ if (extmem)
{
- f << stringf("%s" " %s[%d] = ", indent.c_str(), mem_id.c_str(), i);
- dump_const(f, cell->parameters["\\INIT"].extract(i*width, width));
- f << stringf(";\n");
+ std::string extmem_filename = stringf("%s-%d.mem", extmem_prefix.c_str(), extmem_counter++);
+
+ std::string extmem_filename_esc;
+ for (auto c : extmem_filename)
+ {
+ if (c == '\n')
+ extmem_filename_esc += "\\n";
+ else if (c == '\t')
+ extmem_filename_esc += "\\t";
+ else if (c < 32)
+ extmem_filename_esc += stringf("\\%03o", c);
+ else if (c == '"')
+ extmem_filename_esc += "\\\"";
+ else if (c == '\\')
+ extmem_filename_esc += "\\\\";
+ else
+ extmem_filename_esc += c;
+ }
+ f << stringf("%s" "initial $readmemb(\"%s\", %s);\n", indent.c_str(), extmem_filename_esc.c_str(), mem_id.c_str());
+
+ std::ofstream extmem_f(extmem_filename, std::ofstream::trunc);
+ if (extmem_f.fail())
+ log_error("Can't open file `%s' for writing: %s\n", extmem_filename.c_str(), strerror(errno));
+ else
+ {
+ for (int i=0; i<size; i++)
+ {
+ RTLIL::Const element = cell->parameters["\\INIT"].extract(i*width, width);
+ for (int j=0; j<element.size(); j++)
+ {
+ switch (element[element.size()-j-1])
+ {
+ case State::S0: extmem_f << '0'; break;
+ case State::S1: extmem_f << '1'; break;
+ case State::Sx: extmem_f << 'x'; break;
+ case State::Sz: extmem_f << 'z'; break;
+ case State::Sa: extmem_f << '_'; break;
+ case State::Sm: log_error("Found marker state in final netlist.");
+ }
+ }
+ extmem_f << '\n';
+ }
+ }
+
+ }
+ else
+ {
+ f << stringf("%s" "initial begin\n", indent.c_str());
+ for (int i=0; i<size; i++)
+ {
+ f << stringf("%s" " %s[%d] = ", indent.c_str(), mem_id.c_str(), i);
+ dump_const(f, cell->parameters["\\INIT"].extract(i*width, width));
+ f << stringf(";\n");
+ }
+ f << stringf("%s" "end\n", indent.c_str());
}
- f << stringf("%s" "end\n", indent.c_str());
}
// create a map : "edge clk" -> expressions within that clock domain
@@ -1777,8 +1827,16 @@ struct VerilogBackend : public Backend {
log(" deactivates this feature and instead will write string constants\n");
log(" as binary numbers.\n");
log("\n");
+ log(" -extmem\n");
+ log(" instead of initializing memories using assignments to individual\n");
+ log(" elements, use the '$readmemh' function to read initialization data\n");
+ log(" from a file. This data is written to a file named by appending\n");
+ log(" a sequential index to the Verilog filename and replacing the extension\n");
+ log(" with '.mem', e.g. 'write_verilog -extmem foo.v' writes 'foo-1.mem',\n");
+ log(" 'foo-2.mem' and so on.\n");
+ log("\n");
log(" -defparam\n");
- log(" Use 'defparam' statements instead of the Verilog-2001 syntax for\n");
+ log(" use 'defparam' statements instead of the Verilog-2001 syntax for\n");
log(" cell parameters.\n");
log("\n");
log(" -blackboxes\n");
@@ -1812,6 +1870,7 @@ struct VerilogBackend : public Backend {
nodec = false;
nohex = false;
nostr = false;
+ extmem = false;
defparam = false;
decimal = false;
siminit = false;
@@ -1885,6 +1944,11 @@ struct VerilogBackend : public Backend {
nostr = true;
continue;
}
+ if (arg == "-extmem") {
+ extmem = true;
+ extmem_counter = 1;
+ continue;
+ }
if (arg == "-defparam") {
defparam = true;
continue;
@@ -1912,6 +1976,12 @@ struct VerilogBackend : public Backend {
break;
}
extra_args(f, filename, args, argidx);
+ if (extmem)
+ {
+ if (filename.empty())
+ log_cmd_error("Option -extmem must be used with a filename.\n");
+ extmem_prefix = filename.substr(0, filename.rfind('.'));
+ }
design->sort();