eldo_user

Eldo Netlist Setup
Directives Interpreted by the Eldo Parser (Default)
A definition can be specified in two ways:
• when invoking Eldo with:
eldo -define
• in the netlist with:
#define
...
For example, -define foo on the command line is equivalent to #define foo in the netlist. For
both methods, the netlist statement #ifdef foo will be true.
The #if statement can be used for making complex conditional statements using logical
operators: OR ||, AND &&; and comparison operators: not equal to !=, equal to ==. For
example:
#if (defined(U) || defined(A))
The #if directive can also be used in conjunction with the defined function, that is, if a #define
is active, defined() returns 1 whatever value is assigned to .
Pre-processor commands are position dependent; Eldo behaves like C: the #define is acted upon
only when encountered. In an Eldo (or Questa ADMS mixed-signal) netlist there are normal
SPICE commands and/or netlist pre-processor commands that work completely differently.
SPICE commands are usually position-independent but pre-processor commands beginning
with the # character are position-dependent according to C language.
Examples
V1 1 0 1
#define U 0
#if (defined(U) || defined(A))
R1 1 0 1
#else
R1 1 0 2
#endif
.end
Because U is defined in the above example, defined(U) will return 1. The #if statement is true
and R1 will be set to 1. When the #if statement is substituted with: #if (defined(U) &&
defined(A)), the #if statement will no longer be true because A is not defined. R1 would
therefore be set to 2.
An example of position dependency:
If Eldo is invoked with “a” defined (eldo netlist.cir -define a), in the following:
Eldo® User's Manual, 15.3 123