diff options
Diffstat (limited to 'machxo2/cells.cc')
| -rw-r--r-- | machxo2/cells.cc | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/machxo2/cells.cc b/machxo2/cells.cc index 9b463147..7334234d 100644 --- a/machxo2/cells.cc +++ b/machxo2/cells.cc @@ -154,7 +154,7 @@ void lut_to_lc(const Context *ctx, CellInfo *lut, CellInfo *lc, bool no_dff) replace_port(lut, ctx->id("Z"), lc, ctx->id("F0")); } -void dff_to_lc(Context *ctx, CellInfo *dff, CellInfo *lc, bool pass_thru_lut) +void dff_to_lc(Context *ctx, CellInfo *dff, CellInfo *lc, LutType lut_type) { // FIXME: This will have to change once we support FFs with reset value of 1. lc->params[ctx->id("REG0_REGSET")] = std::string("RESET"); @@ -163,14 +163,21 @@ void dff_to_lc(Context *ctx, CellInfo *dff, CellInfo *lc, bool pass_thru_lut) replace_port(dff, ctx->id("LSR"), lc, ctx->id("LSR")); replace_port(dff, ctx->id("Q"), lc, ctx->id("Q0")); - // If a register's DI port is fed by a constant, options for placing are - // limited. Use the LUT to get around this. - if (pass_thru_lut) { + if (lut_type == LutType::PassThru) { + // If a register's DI port is fed by a constant, options for placing are + // limited. Use the LUT to get around this. + // LUT output will go to F0, which will feed back to DI0 input. lc->params[ctx->id("LUT0_INITVAL")] = Property(0xAAAA, 16); - ; replace_port(dff, ctx->id("DI"), lc, ctx->id("A0")); connect_ports(ctx, lc, ctx->id("F0"), lc, ctx->id("DI0")); + } else if (lut_type == LutType::None) { + // If there is no LUT, use the M0 input because DI0 requires + // going through the LUTs. + lc->params[ctx->id("REG0_SD")] = std::string("0"); + replace_port(dff, ctx->id("DI"), lc, ctx->id("M0")); } else { + // Otherwise, there's a LUT being used in the slice and mapping DI to + // DI0 input is fine. replace_port(dff, ctx->id("DI"), lc, ctx->id("DI0")); } } |