mirrors/yosys
3
0
Fork 0
mirror of https://github.com/YosysHQ/yosys synced 2026-05-05 01:45:17 +00:00
Code Activity

Consolidate Wallace from booth and CSA.

Browse source
This commit is contained in:
nella 2026-04-01 11:03:41 +02:00 • committed by nella
parent 4bbffecf98
commit a02c238874
3 changed files with 124 additions and 106 deletions
Download patch file Download diff file Expand all files Collapse all files

39
passes/techmap/booth.cc
View file

@ -58,6 +58,7 @@ synth -top my_design -booth
#include "kernel/sigtools.h"
#include "kernel/yosys.h"
#include "kernel/macc.h"
#include "kernel/wallace_tree.h"
USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN
@ -317,36 +318,6 @@ struct BoothPassWorker {
}
}
SigSig WallaceSum(int width, std::vector<SigSpec> summands)
{
for (auto &s : summands)
s.extend_u0(width);
while (summands.size() > 2) {
std::vector<SigSpec> new_summands;
int i;
for (i = 0; i < (int) summands.size() - 2; i += 3) {
SigSpec x = module->addWire(NEW_ID, width);
SigSpec y = module->addWire(NEW_ID, width);
BuildBitwiseFa(module, NEW_ID.str(), summands[i], summands[i + 1],
summands[i + 2], x, y);
new_summands.push_back(y);
new_summands.push_back({x.extract(0, width - 1), State::S0});
}
new_summands.insert(new_summands.begin(), summands.begin() + i, summands.end());
std::swap(summands, new_summands);
}
if (!summands.size())
return SigSig(SigSpec(width, State::S0), SigSpec(width, State::S0));
else if (summands.size() == 1)
return SigSig(summands[0], SigSpec(width, State::S0));
else
return SigSig(summands[0], summands[1]);
}
/*
Build Multiplier.
-------------------------
@ -415,16 +386,16 @@ struct BoothPassWorker {
// Later on yosys will clean up unused constants
// DebugDumpAlignPP(aligned_pp);
SigSig wtree_sum = WallaceSum(z_sz, aligned_pp);
auto [wtree_a, wtree_b] = wallace_reduce_scheduled(module, aligned_pp, z_sz);
// Debug code: Dump out the csa trees
// DumpCSATrees(debug_csa_trees);
// Build the CPA to do the final accumulation.
log_assert(wtree_sum.second[0] == State::S0);
log_assert(wtree_b[0] == State::S0);
if (mapped_cpa)
BuildCPA(module, wtree_sum.first, {State::S0, wtree_sum.second.extract_end(1)}, Z);
BuildCPA(module, wtree_a, wtree_b, Z);
else
module->addAdd(NEW_ID, wtree_sum.first, {wtree_sum.second.extract_end(1), State::S0}, Z);
module->addAdd(NEW_ID, wtree_a, wtree_b, Z);
}
/*