About Include

Directory include contains definitions and top-level parameters.

Naming Rule

All definitions and parameters use this naming rule

[<hierachy>_]<type>_<object>_<modifier0>_..._<modifierN>[_(WD|BP)]

1. <hierachy> refer to the short name of hierarchies, which usually use 3 letters.

   For example,

   hierachy calc_add_top related definitions and parameters can be prefixed with ADD_;

   hierachy calc_sub_top related definitions and parameters can be prefixed with SUB_;

   hierachy calc_mul_top related definitions and parameters can be prefixed with MUL_;

   hierachy calc_div_top related definitions and parameters can be prefixed with DIV_;

   hierachy calc_reg related definitions and parameters can be prefixed with CTL_ (control registers), CFG_ (configuration registers) and FDB_ (feedback regsiters);

   hierachy calc_knl_top related definitions and parameters can be prefixed with KNL_;

   hierachy calc_itf_top related definitions and parameters can be prefixed with ITF_;

   hierachy calc_top related definitions and parameters can be prefixed with TOP_, but it is usually omitted.

2. <type> includes the following items, which use 4 letters.

   <type>	description	postscript
   KNOB	existence	exists if defined
   FLAG	enabling	enabled if configured with 1
   NUMB	number
   SIZE	size
   ENUM	enumerator
   DATA	value
   CSTR	string
   FUNC	function

3. <object> refer to the short name of objects. For example,

   <object>	description
   FRAME	frame
   UNIT	unit
   REG	register
   SRAM	sram
   SCL	scaler
   DELAY	delay

4. <modifier> refer to the short name of modifiers, which usually use 3 letters. For example,

   <modifier>	description
   MAX	maximum
   MIN	minimum
   BFR	before
   AFT	after
   IN	input
   OUT	output

Hierarchy

The hierarchy of this RTL example’s definitions contains three levels, which are top level, IP level, and module level.

• Top-level definitions are collected in file define.vh and shared by all the designs.

• IP-level definitions are collected in file define_calc.vh and shared by all the designs under calc_top.

• Module-level definitions are collected in file define_calc_add.vh, define_calc_sub.vh, define_calc_mul.vh, define_calc_div.vh and shared by all the designs under calc_add, calc_sub, calc_mul and calc_div respectively.

include iteratively

Obviously,

designs which includes file define_calc_add.vh must include file define_calc.vh,

designs which includes file define_calc.vh must include file define.vh.

As a result, I directly

include file define.vh in file define_calc.vh,

include file define_calc.vh in file define_calc_add.vh.

In this way, each design file could include just one definition file,

and a definition file in a lower level would include a definition file in a higher level.

isolate with undef

In order to keep the definitions in file define_calc_add.vh invisible to other unrelated modules,

I have created a corresponding “undef” file undef_calc_add.vh, which “undefs” every definition in file define_calc_add.v.

Due to the same reason, other definition files except file define.vh also have the corresponding “undef” files.

In this way, definitions of modules and IPs can be isolated from each other.

This is meaningful since multiple modules would exist in one IP and multiple IPs would exist in one “top”.

diagram

A simplified diagram is given to illustrate the above two tricks.