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ice40: Working on the placement legaliser

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Signed-off-by: David Shah <davey1576@gmail.com>
This commit is contained in:
David Shah 2018-06-25 16:15:47 +02:00
parent 6d154cfa13
commit bee6bc461d
1 changed files with 43 additions and 4 deletions
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47
ice40/place_legaliser.cc
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@ -66,11 +66,11 @@ std::vector<CellChain> find_chains(const Context *ctx, F1 cell_type_predicate, F
return chains;
}
static void get_chain_midpoint(const Context *ctx, const std::vector<CellInfo *> &chain, float &x, float &y)
static void get_chain_midpoint(const Context *ctx, const CellChain &chain, float &x, float &y)
{
float total_x = 0, total_y = 0;
int N = 0;
for (auto cell : chain) {
for (auto cell : chain.cells) {
if (cell->bel == BelId())
continue;
int bel_x, bel_y;
@ -89,6 +89,7 @@ class PlacementLegaliser
{
public:
PlacementLegaliser(Context *ctx) : ctx(ctx){};
bool legalise()
{
bool legalised_carries = legalise_carries();
@ -98,6 +99,27 @@ class PlacementLegaliser
}
private:
void init_logic_cells()
{
for (auto bel : ctx->getBels()) {
// Initialise the logic bels vector with unavailable invalid bels, dimensions [0..width][0..height[0..7]
logic_bels.resize(ctx->chip_info->width + 1,
std::vector<std::vector<std::pair<BelId, bool>>>(
ctx->chip_info->height + 1,
std::vector<std::pair<BelId, bool>>(8, std::make_pair(BelId(), true))));
if (ctx->getBelType(bel) == TYPE_ICESTORM_LC) {
// Using the non-standard API here to get (x, y, z) rather than just (x, y)
auto bi = ctx->chip_info->bel_data[bel.index];
int x = bi.x, y = bi.y, z = bi.z;
IdString cell = ctx->getBoundBelCell(bel);
if (cell != IdString() && ctx->cells.at(cell)->belStrength >= STRENGTH_FIXED)
logic_bels.at(x).at(y).at(z) = std::make_pair(bel, true);
else
logic_bels.at(x).at(y).at(z) = std::make_pair(bel, false);
}
}
}
bool legalise_carries()
{
std::vector<CellChain> carry_chains = find_chains(
@ -108,13 +130,28 @@ class PlacementLegaliser
[](const Context *ctx, const CellInfo *cell) {
return net_only_drives(ctx, cell->ports.at(ctx->id("COUT")).net, is_lc, ctx->id("CIN"), false);
});
for (auto chain : carry_chains) {
int width = ctx->chip_info->width, height = ctx->chip_info->height;
for (auto &base_chain : carry_chains) {
std::vector<CellChain> split_chains = split_carry_chain(base_chain);
for (auto &chain : split_chains) {
float mid_x, mid_y;
get_chain_midpoint(ctx, chain, mid_x, mid_y);
float base_x = mid_x, base_y = mid_y - (chain.cells.size() / 16.0f);
// Find Bel meeting requirements closest to the target base
}
}
return true;
}
// Find Bel closest to a location, meeting chain requirements
BelId find_closest_bel(float x, float y, int chain_size)
{
// TODO
return BelId();
}
// Split a carry chain into multiple legal chains
std::vector<CellChain> split_carry_chain(Context *ctx, CellChain &carryc)
std::vector<CellChain> split_carry_chain(CellChain &carryc)
{
bool start_of_chain = true;
std::vector<CellChain> chains;
@ -213,6 +250,8 @@ class PlacementLegaliser
Context *ctx;
std::unordered_set<IdString> rippedCells;
std::unordered_set<IdString> createdCells;
// Go from X and Y position to logic cells, setting occupied to true if a Bel is unavailable
std::vector<std::vector<std::vector<std::pair<BelId, bool>>>> logic_bels;
};
bool legalise_design(Context *ctx)