基本仿真命令

通常一个典型的NC仿真命令是这样的：

irun -sv -access rwc *.sv -define rtl_sim  -input run.tcl&

其中-access rwc 表示NC生成的波形是可读可写可连接的，如果要开波形，必须加这个选项； -input run.tcl表示你需要传递进来一个tcl文件来控制仿真，例如想为Verdi dump fsdb文件而又不想放在TB里做。我的一个典型run.tcl是这样的：

call fsdbDumpfile tb_top.fsdb

call fsdbDumpvars 0 tb_top

run

exit

irun: 12.20-s029: (c) Copyright 1995-2014 Cadence Design Systems, Inc.

Usage:

                irun [options] files

                  File languages:  Verilog, SystemVerilog, VHDL, e, System-C, C, C++

                  In addition to the dash options all ncverilog plus options can be used.

                  Options shown below in lowercase can also be entered in uppercase.

                    For example, both -top and -TOP are valid.

                If you need more information about an option listed below, use the search

                facility in the online help system. In the "Search for" text box,

                enter the name of the option, including the dash.  The dash must be escaped.

                   (\-profile, for example)

  -helpall                   Display all supported option

  -helphelp                  Print out all the options controlling help

  -helpsubject <subject>     Display help on the specified subject

  -helpshowsubject           Show all the subjects for -helpsubject

  -64bit                     Invoke 64bit version

  -gui                       Invoke the Graphical User Interface

  -q                         Suppress informational messages(i.e., Quiet mode)

  -f <filename>              Scan file for args relative to irun invocation

  -elaborate                 Parse and elaborate, do NOT simulate

  -R                         Simulate using the last ncelab generated snapshot

  -incdir <dirs>             Specify directories to search for `include files

  -v <file>                  Specify a library file to be used

  -y <directory>             Specify a library directory to be used

  -libext <ext>              Specify extensions to be used for the -y search

  -top <lib.cell:view>       Specify the top-level unit

  -l <filename>              Set logfile name

  -access <+/-rwc>           Turn on read, write and/or connectivity access

  -input <file>              Read TCL commands from file

  -define <macro>            Define a macro from command line

  -pragma                    Enable pragma processing

  -gateloopwarn              Enable potential zero-delay gate loop warning

  -coverage <string>         Enable coverage instrumentation

  -assert                    Enable PSL language features

  -nospecify                 Suppress timing information from specify blocks

  -extbind <arg>             Option for SV binds in textfile.

  -parseinfo include=<du>    Enable verbose information for tick-include

Example commands to invoke irun

  irun sio85.v

  irun xor.v bot.vhd xor_verify.e

  irun -f run.f

  irun a.v b.v c.vhd -c

  irun -R -input commands.tcl

  irun -helpsubject specman

高级用法——NC通过参数传递变量

Nc-verilog仿真工具可以通过参数向测试环境传递参数，我猜测这样做的好处是可以不必重新编译。具体做法是在ncsim这个命令选项后加参数，例如：

ncsim +test_num=5 +num_events=40000 top

然后在testbench中可以这样把两个变量传递进来：

      if($value$plusargs("test_num=%d", test_num))

                $display ("Running test number %d",test_num);

      if($value$plusargs("num_events=%d", num_events))

                $display ("Running %d number of events",num_events);