diff options
Diffstat (limited to 'ecp5/pack.cc')
| -rw-r--r-- | ecp5/pack.cc | 74 |
1 files changed, 65 insertions, 9 deletions
diff --git a/ecp5/pack.cc b/ecp5/pack.cc index d8db3b93..14b387d5 100644 --- a/ecp5/pack.cc +++ b/ecp5/pack.cc @@ -637,14 +637,12 @@ class Ecp5Packer flush_cells(); } - void set_lut_input_constant(CellInfo *cell, IdString input, bool value) + int make_init_with_const_input(int init, int input, bool value) { - int index = std::string("ABCD").find(input.str(ctx)); - int init = int_or_default(cell->params, ctx->id("INIT")); int new_init = 0; for (int i = 0; i < 16; i++) { - if (((i >> index) & 0x1) != value) { - int other_i = (i & (~(1 << index))) | (value << index); + if (((i >> input) & 0x1) != value) { + int other_i = (i & (~(1 << input))) | (value << input); if ((init >> other_i) & 0x1) new_init |= (1 << i); } else { @@ -652,10 +650,41 @@ class Ecp5Packer new_init |= (1 << i); } } + return new_init; + } + + void set_lut_input_constant(CellInfo *cell, IdString input, bool value) + { + int index = std::string("ABCD").find(input.str(ctx)); + int init = int_or_default(cell->params, ctx->id("INIT")); + int new_init = make_init_with_const_input(init, index, value); cell->params[ctx->id("INIT")] = std::to_string(new_init); cell->ports.at(input).net = nullptr; } + void set_ccu2c_input_constant(CellInfo *cell, IdString input, bool value) + { + std::string input_str = input.str(ctx); + int lut = std::stoi(input_str.substr(1)); + int index = std::string("ABCD").find(input_str[0]); + int init = int_or_default(cell->params, ctx->id("INIT" + std::to_string(lut))); + int new_init = make_init_with_const_input(init, index, value); + cell->params[ctx->id("INIT" + std::to_string(lut))] = std::to_string(new_init); + cell->ports.at(input).net = nullptr; + } + + bool is_ccu2c_port_high(CellInfo *cell, IdString input) + { + if (!cell->ports.count(input)) + return true; // disconnected port is high + if (cell->ports.at(input).net == nullptr || cell->ports.at(input).net->name == ctx->id("$PACKER_VCC_NET")) + return true; // disconnected or tied-high port + if (cell->ports.at(input).net->driver.cell != nullptr && + cell->ports.at(input).net->driver.cell->type == ctx->id("VCC")) + return true; // pre-pack high + return false; + } + // Merge a net into a constant net void set_net_constant(const Context *ctx, NetInfo *orig, NetInfo *constnet, bool constval) { @@ -670,10 +699,37 @@ class Ecp5Packer } else if (is_ff(ctx, uc) && user.port == ctx->id("CE")) { uc->params[ctx->id("CEMUX")] = constval ? "1" : "0"; uc->ports[user.port].net = nullptr; - } else if (is_carry(ctx, uc) && constval && - (user.port == id_A0 || user.port == id_A1 || user.port == id_B0 || user.port == id_B1 || - user.port == id_C0 || user.port == id_C1 || user.port == id_D0 || user.port == id_D1)) { - uc->ports[user.port].net = nullptr; + } else if (is_carry(ctx, uc)) { + if (constval && + (user.port == id_A0 || user.port == id_A1 || user.port == id_B0 || user.port == id_B1 || + user.port == id_C0 || user.port == id_C1 || user.port == id_D0 || user.port == id_D1)) { + // Input tied high, nothing special to do (bitstream gen will auto-enable tie-high) + uc->ports[user.port].net = nullptr; + } else if (!constval) { + if (user.port == id_A0 || user.port == id_A1 || user.port == id_B0 || user.port == id_B1) { + // These inputs can be switched to tie-high without consequence + set_ccu2c_input_constant(uc, user.port, constval); + } else if (user.port == id_C0 && is_ccu2c_port_high(uc, id_D0)) { + // Partner must be tied high + set_ccu2c_input_constant(uc, user.port, constval); + } else if (user.port == id_D0 && is_ccu2c_port_high(uc, id_C0)) { + // Partner must be tied high + set_ccu2c_input_constant(uc, user.port, constval); + } else if (user.port == id_C1 && is_ccu2c_port_high(uc, id_D1)) { + // Partner must be tied high + set_ccu2c_input_constant(uc, user.port, constval); + } else if (user.port == id_D1 && is_ccu2c_port_high(uc, id_C1)) { + // Partner must be tied high + set_ccu2c_input_constant(uc, user.port, constval); + } else { + // Not allowed to change to a tie-high + uc->ports[user.port].net = constnet; + constnet->users.push_back(user); + } + } else { + uc->ports[user.port].net = constnet; + constnet->users.push_back(user); + } } else if (is_ff(ctx, uc) && user.port == ctx->id("LSR") && ((!constval && str_or_default(uc->params, ctx->id("LSRMUX"), "LSR") == "LSR") || (constval && str_or_default(uc->params, ctx->id("LSRMUX"), "LSR") == "INV"))) { |