matthew1kalasky3
/
microwatt
forked from cores/microwatt
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Reduce Yosys ECP5 cell usage by 30% with -abc9 -nowidelut

Browse Source 
We've been investigating why the barrel rotator uses an enormous
number of cells on the yosys ECP5 target. Eventually it was narrowed
down to the -abc9 -nowidelut options, which see the cell count go from
4985 cells to 841 cells.

Using the same options on an Orange Crab build reduces the cell count
from 50864 to 36085. The main differences:

     LUT4                        31040 -> 25270
     PFUMX                        6956 ->     0
     L6MUX21                      1746 ->     0
     CCU2C                        2066 ->  1759

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
remove-potato-uart
Anton Blanchard 3 years ago committed by Anton Blanchard
parent aa4e4e77c4
commit 6254bb5ee9
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File

2
Makefile
Unescape Escape View File

@ -196,7 +196,7 @@ fpga_files = fpga/soc_reset.vhdl \
synth_files = $(core_files) $(soc_files) $(fpga_files) $(clkgen) $(toplevel) $(dmi_dtm) synth_files = $(core_files) $(soc_files) $(fpga_files) $(clkgen) $(toplevel) $(dmi_dtm)


microwatt.json: $(synth_files) $(RAM_INIT_FILE) microwatt.json: $(synth_files) $(RAM_INIT_FILE)
$(YOSYS) -m $(GHDLSYNTH) -p "ghdl --std=08 --no-formal $(GHDL_IMAGE_GENERICS) $(synth_files) -e toplevel; synth_ecp5 -json $@ $(SYNTH_ECP5_FLAGS)" $(uart_files) $(YOSYS) -m $(GHDLSYNTH) -p "ghdl --std=08 --no-formal $(GHDL_IMAGE_GENERICS) $(synth_files) -e toplevel; synth_ecp5 -abc9 -nowidelut -json $@ $(SYNTH_ECP5_FLAGS)" $(uart_files)


microwatt.v: $(synth_files) $(RAM_INIT_FILE) microwatt.v: $(synth_files) $(RAM_INIT_FILE)
$(YOSYS) -m $(GHDLSYNTH) -p "ghdl --std=08 --no-formal $(GHDL_IMAGE_GENERICS) $(synth_files) -e toplevel; write_verilog $@" $(YOSYS) -m $(GHDLSYNTH) -p "ghdl --std=08 --no-formal $(GHDL_IMAGE_GENERICS) $(synth_files) -e toplevel; write_verilog $@"

Write Preview
Loading…
Cancel
Save