diff options
| author | gatecat <gatecat@ds0.me> | 2021-05-15 14:40:37 +0100 |
|---|---|---|
| committer | gatecat <gatecat@ds0.me> | 2021-05-15 22:37:06 +0100 |
| commit | 34a08750fa1a490be09411b07f64f4236eff234e (patch) | |
| tree | 5fbb25ea584e2183d57d4a2de46d23cdd1438497 /techlibs | |
| parent | eb106732d94322fb5b48fbff0420ce5a6fc83eb9 (diff) | |
| download | yosys-34a08750fa1a490be09411b07f64f4236eff234e.tar.gz yosys-34a08750fa1a490be09411b07f64f4236eff234e.tar.bz2 yosys-34a08750fa1a490be09411b07f64f4236eff234e.zip | |
intel_alm: Fix illegal carry chains
Signed-off-by: gatecat <gatecat@ds0.me>
Diffstat (limited to 'techlibs')
| -rw-r--r-- | techlibs/intel_alm/common/alm_sim.v | 6 | ||||
| -rw-r--r-- | techlibs/intel_alm/common/arith_alm_map.v | 2 |
2 files changed, 5 insertions, 3 deletions
diff --git a/techlibs/intel_alm/common/alm_sim.v b/techlibs/intel_alm/common/alm_sim.v index 906a95b0b..6e70be865 100644 --- a/techlibs/intel_alm/common/alm_sim.v +++ b/techlibs/intel_alm/common/alm_sim.v @@ -230,8 +230,10 @@ assign Q = ~A; endmodule -(* abc9_box, lib_whitebox *) -module MISTRAL_ALUT_ARITH(input A, B, C, D0, D1, (* abc9_carry *) input CI, output SO, (* abc9_carry *) output CO); +// Despite the abc9_carry attributes, this doesn't seem to stop ABC9 adding illegal fanout to the carry chain that nextpnr cannot handle. +// So we treat it as a total blackbox from ABC9's perspective for now. +// (* abc9_box, lib_whitebox *) +module MISTRAL_ALUT_ARITH(input A, B, C, D0, D1, /* (* abc9_carry *) */ input CI, output SO, /* (* abc9_carry *) */ output CO); parameter LUT0 = 16'h0000; parameter LUT1 = 16'h0000; diff --git a/techlibs/intel_alm/common/arith_alm_map.v b/techlibs/intel_alm/common/arith_alm_map.v index 8515eeb56..7cbf02e9c 100644 --- a/techlibs/intel_alm/common/arith_alm_map.v +++ b/techlibs/intel_alm/common/arith_alm_map.v @@ -34,7 +34,7 @@ wire [Y_WIDTH:0] ALM_CARRY; // Start of carry chain generate - if (_TECHMAP_CONSTMSK_CI_ == 1) begin + if (_TECHMAP_CONSTMSK_CI_ == 1 && _TECHMAP_CONSTVAL_CI_ == 1'b0) begin assign ALM_CARRY[0] = _TECHMAP_CONSTVAL_CI_; end else begin MISTRAL_ALUT_ARITH #( |