3
0
Fork 0
mirror of https://github.com/YosysHQ/yosys synced 2025-08-11 21:50:54 +00:00

xilinx: Improve flip-flop handling.

This adds support for infering more kinds of flip-flops:

- FFs with async set/reset and clock enable
- FFs with sync set/reset
- FFs with sync set/reset and clock enable

Some passes have been moved (and some added) in order for dff2dffs to
work correctly.

This gives us complete coverage of Virtex 6+ and Spartan 6 flip-flop
capabilities (though not latch capabilities).  Older FPGAs also support
having both a set and a reset input, which will be handled at a later
data.
This commit is contained in:
Marcin Kościelnicki 2019-11-21 06:30:06 +01:00 committed by Marcin Kościelnicki
parent 22dd9f107c
commit aff6ad1ce0
8 changed files with 264 additions and 71 deletions

View file

@ -50,6 +50,8 @@ Yosys 0.9 .. Yosys 0.9-dev
- "synth_ecp5" to now infer DSP blocks (-nodsp to disable, experimental)
- "synth_ice40 -dsp" to infer DSP blocks
- Added latch support to synth_xilinx
- Added support for flip-flops with synchronous reset to synth_xilinx
- Added support for flip-flops with reset and enable to synth_xilinx
- Added "check -mapped"
- Added checking of SystemVerilog always block types (always_comb,
always_latch and always_ff)