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Carry in/out to be the last input/output for chains to be preserved

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This commit is contained in:
Eddie Hung 2019-05-30 01:23:36 -07:00
parent 8c58c728a7
commit fdfc18be91
4 changed files with 91 additions and 12 deletions
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38
backends/aiger/xaiger.cc
View file

@ -298,6 +298,8 @@ struct XAigerWriter
for (auto user_cell : it.second)
toposort.edge(driver_cell, user_cell);
pool<RTLIL::Module*> abc_carry_modules;
toposort.sort();
for (auto cell_name : toposort.sorted) {
RTLIL::Cell *cell = module->cell(cell_name);
@ -305,6 +307,42 @@ struct XAigerWriter
if (!box_module || !box_module->attributes.count("\\abc_box_id"))
continue;
if (box_module->attributes.count("\\abc_carry") && !abc_carry_modules.count(box_module)) {
RTLIL::Wire* carry_in = nullptr, *carry_out = nullptr;
RTLIL::Wire* last_in = nullptr, *last_out = nullptr;
for (const auto &port_name : box_module->ports) {
RTLIL::Wire* w = box_module->wire(port_name);
log_assert(w);
if (w->port_input) {
if (w->attributes.count("\\abc_carry_in")) {
log_assert(!carry_in);
carry_in = w;
}
log_assert(!last_in || last_in->port_id < w->port_id);
last_in = w;
}
if (w->port_output) {
if (w->attributes.count("\\abc_carry_out")) {
log_assert(!carry_out);
carry_out = w;
}
log_assert(!last_out || last_out->port_id < w->port_id);
last_out = w;
}
}
if (carry_in) {
log_assert(last_in);
std::swap(box_module->ports[carry_in->port_id-1], box_module->ports[last_in->port_id-1]);
std::swap(carry_in->port_id, last_in->port_id);
}
if (carry_out) {
log_assert(last_out);
std::swap(box_module->ports[carry_out->port_id-1], box_module->ports[last_out->port_id-1]);
std::swap(carry_out->port_id, last_out->port_id);
}
}
// Fully pad all unused input connections of this box cell with S0
// Fully pad all undriven output connections of this box cell with anonymous wires
// NB: Assume box_module->ports are sorted alphabetically

38
frontends/aiger/aigerparse.cc
View file

@ -549,6 +549,7 @@ void AigerReader::post_process()
std::string type, symbol;
int variable, index;
int pi_count = 0, ci_count = 0, co_count = 0;
pool<RTLIL::Module*> abc_carry_modules;
while (mf >> type >> variable >> index >> symbol) {
RTLIL::IdString escaped_s = RTLIL::escape_id(symbol);
if (type == "input") {
@ -646,6 +647,43 @@ void AigerReader::post_process()
module->rename(cell, escaped_s);
RTLIL::Module* box_module = design->module(cell->type);
log_assert(box_module);
if (box_module->attributes.count("\\abc_carry") && !abc_carry_modules.count(box_module)) {
RTLIL::Wire* carry_in = nullptr, *carry_out = nullptr;
RTLIL::Wire* last_in = nullptr, *last_out = nullptr;
for (const auto &port_name : box_module->ports) {
RTLIL::Wire* w = box_module->wire(port_name);
log_assert(w);
if (w->port_input) {
if (w->attributes.count("\\abc_carry_in")) {
log_assert(!carry_in);
carry_in = w;
}
log_assert(!last_in || last_in->port_id < w->port_id);
last_in = w;
}
if (w->port_output) {
if (w->attributes.count("\\abc_carry_out")) {
log_assert(!carry_out);
carry_out = w;
}
log_assert(!last_out || last_out->port_id < w->port_id);
last_out = w;
}
}
if (carry_in != last_in) {
std::swap(box_module->ports[carry_in->port_id], box_module->ports[last_in->port_id]);
std::swap(carry_in->port_id, last_in->port_id);
}
if (carry_out != last_out) {
log_assert(last_out);
std::swap(box_module->ports[carry_out->port_id], box_module->ports[last_out->port_id]);
std::swap(carry_out->port_id, last_out->port_id);
}
}
// NB: Assume box_module->ports are sorted alphabetically
// (as RTLIL::Module::fixup_ports() would do)
for (auto port_name : box_module->ports) {

23
techlibs/xilinx/abc.box
View file

@ -12,17 +12,20 @@ MUXF8 2 1 3 1
104 94 273
# CARRY4 + CARRY4_[ABCD]X
# Inputs: CI CYINIT DI0 DI1 DI2 DI3 S0 S1 S2 S3
# Outputs: CO0 CO1 CO2 CO3 O0 O1 O2 O3
# Inputs: S0 S1 S2 S3 CYINIT DI0 DI1 DI2 DI3 CI
# Outputs: O0 O1 O2 O3 CO0 CO1 CO2 CO3
# (NB: carry chain input/output must be last input/output,
# swapped with what normally would have been the last
# output, here: CI <-> S, CO <-> O
CARRY4 3 1 10 8
271 536 379 - - - 340 - - -
157 494 465 445 - - 433 469 - -
228 592 540 520 356 - 512 548 292 -
114 580 526 507 398 385 508 528 378 380
222 482 - - - - 223 - - -
334 598 407 - - - 400 205 - -
239 584 556 537 - - 523 558 226 -
313 642 615 596 438 - 582 618 330 227
223 - - - 482 - - - - 222
400 205 - - 598 407 - - - 334
523 558 226 - 584 556 537 - - 239
582 618 330 227 642 615 596 438 - 313
340 - - - 536 379 - - - 271
433 469 - - 494 465 445 - - 157
512 548 292 - 592 540 520 356 - 228
508 528 378 380 580 526 507 398 385 114
# SLICEM/A6LUT
# Inputs: A0 A1 A2 A3 A4 A5 D DPRA0 DPRA1 DPRA2 DPRA3 DPRA4 DPRA5 WCLK WE

4
techlibs/xilinx/cells_sim.v
View file

@ -173,8 +173,8 @@ module XORCY(output O, input CI, LI);
assign O = CI ^ LI;
endmodule
(* abc_box_id = 3, lib_whitebox *)
module CARRY4(output [3:0] CO, O, input CI, CYINIT, input [3:0] DI, S);
(* abc_box_id = 3, lib_whitebox, abc_carry *)
module CARRY4((* abc_carry_out *) output [3:0] CO, output [3:0] O, (* abc_carry_in *) input CI, input CYINIT, input [3:0] DI, S);
assign O = S ^ {CO[2:0], CI | CYINIT};
assign CO[0] = S[0] ? CI | CYINIT : DI[0];
assign CO[1] = S[1] ? CO[0] : DI[1];