Vlog Mode for Emacs
Brief Overview of Features
- Has lots of automatic templates that insert code for you. For
example, if you type "case ", it will ask you for the name of the
signal to switch on, insert the case statement with begin and endcase,
and then ask for the particular cases.
- Most of the templates are bound to control keys. For example, C-c
C-b causes vlog-mode to insert a begin-end pair at the current point.
- Colorization of text is the same as Verilog-mode (with a couple of
minor additions).
- Vlog-mode treats variable names that include an underscore as a
single word. This allows operations like forward-word to work
correctly.
- Using M-/, (Escape then /), causes variable name completion. This
way you can have long descriptive signal names without having to type
as much.
- High level functions such as "update module port list from
input/output declarations" and "instantiate module", which
automatically do some of the tedious processes of connecting
modules.
- Tabbing is different than Verilog mode.
Enabling Vlog-mode
If you use Bill Mann's standard .emacs file, and you have the latest
copy, then Vlog-mode will be enabled automatically. Otherwise, you
should
add this code to your .emacs file
to enable Vlog-mode.
Features in Detail
Tabs
The Tab key operates differently in Vlog mode than in Verilog mode.
- If the cursor is at the beginning, Tab will tab over to line up with
the start of code in the previous line.
- If the cursor is on the first character of the line of code, and this
position is the same as or greater than the start of the previous line,
insert a tab of vlog-indent-level length.
- If the cursor is in the middle of a line of text or at the end of a
line of text, the Tab key will move the line to line up with the previous
line.
Auto-Inserting Code
Typing many common keywords will cause a template to execute that will
assist in your code writing. The user will be prompted for variable
names at certain times. All these templates can be individually
modified in your personal .emacs file, or globally disabled. I give
examples of both under Customization.
Useful key bindings and functions
C-c C-b Insert begin/end pair with blank line in between
C-c C-a Insert always block. It prompts for sensitivity list
C-c C-f (vlog-find-file) If point rests on a verilog module name,
that module_name.v will be opened from the current directory.
C-c i (vlog-if-else-begin) Insert an if-else block
C-c m (vlog-insert-module-instance) Insert module instantiation.
Prompts for filename of module.
C-c e (vlog-enable-reg) Insert a inferred flip-flop with enable
C-c r (vlog-std-reg) Insert an inferred flip-flop
C-c ] (end-of-vlog-module)
C-c [ (beginning-of-vlog-module)
,, (stutter-comma) Typing two commas replaces the commas with " <= "
Quickly declaring wires and registers
I've made a couple of short cuts for declaring regs and wires, while
you're coding. These functions take the name of the reg/wire that
your cursor is on top of, asks for the bus width of the signal, and
puts a reg or wire declaration at the top of your code. You don't see
this happen; your view of the code is unchanged. It makes it easy to
declare these as your are writing or adding code.
The regs/wires declarations are all positioned underneath a text
string declared in the variable vlog-local-regs-wires-str. The
default value is the string "//### local regs/wires".
C-c g (vlog-declare-reg) Declares a reg for the signal that the
cursor is on.
C-c w (vlog-declare-wire) Declares a wire for the signal that the
cursor is on.
Functions for Structural Level Connectivity
- vlog-insert-module-instance This function reads a
file and instantiates a port-by-name instance. It also creates wire
declarations for each port signal. These wire declarations can then
be moved to the top of the module.
- vlog-update-module-ports This function will update
the port list of the current module from the input, output, and inout
declarations.
- vlog-update-module-instance Point must be
somewhere in the module to be updated. If the module is in the same
dir as the current buffer's file, the module instance will be updated,
ie. deleted and re-instantiated.
Restrictions on I/O declarations: The above three functions
operate best when only 1 signal name used per input, output or inout
declaration.
Modifying Automatic Instance Names
The default module instance name used in
vlog-insert-module-instance is umodule_name
. After instantiation, the cursor is left next to the instance
name, for manual modification, if necessary. I have also added some
controls to the automatic instance name generation.
- vlog-use-u Set to nil to disable adding the "u" to
the instance name. Default is true.
- vlog-shorten-instance-names Setting this 't will enable
the use of vlog-shorten-inst-len. Default is false.
- vlog-shorten-inst-len Specifies the number of
characters to delete from the beginning of the module_name when creating
an instance. Eg. If the module is oboe_flit_fwd.v, vlog-shorten-instance-names
is true, vlog-use-u is true, and vlog-shorten-inst-len
is set to 5, then the module instance name will be uflit_fwd.
To set any of these variables, use the following example. Note that
true is 't in emacs-lisp and false is nil.
(add-hook 'vlog-mode-hook (function (lambda () (setq
vlog-shorten-instance-name 't))))
Customization
Examples of things to add to your .emacs file to customize Vlog-mode:
Known Bugs (and workarounds)
- If C-style comment (/* ... */) is the very first character in the
file, keyword expansion will occur within that comment.
Workaround: Don't do that! If necessary, start first line of
file with "//" comments.