This is set of VHDL examples and how to simuate and check results on MacOS.

• install GHDL from its github

• install gtkwave viewer to see simulation results, it can be done using homebrew on MacOS and it will be installed as App (launch from spotlight)

Breefly about necessary steps for using ghdl to simulate VHDL designs (some examples can be found here):

• create you vhdl design, save it in code editor (example from combinational_logic)

• analyze your design in console ghdl -a comb_ckt.vhd

• analyze your test bench desing ghdl -a --ieee=synopsys comb_ckt_tb.vhd

• create executable ghdl -e --ieee=synopsys CKT_TB, CKT_TB is entity described in testbench

• run the testbench ghdl -r --ieee=synopsys CKT_TB

• you can add signals output when runing ghdl -r --ieee=synopsys CKT_TB --vcd=CKT_TB.vcd

• to see results in gtkwave app run open CKT_TB.vcd from terminal

Some errors I encontered:

• error unit "std_logic_arith" not found in library "ieee", so to fix this run ghdl -a --ieee=synopsys design.vhd