Echelon Neuron C - Manual (Page 50)

30 Compiler Directives
Development Tool, valid values for num are 0 to 127. In Neuron C Version
2.2 (and later), there is no compiler default for this value. A Neuron C
program must specify a value using this pragma. You can use this pragma to
trade EEPROM space for alias table entries (see Chapter 8, Memory
Management, of the Neuron C Programmer’s Guide ).
This directive is not supported in model files.
#pragma num_domain_entries num
Sets the number of domain table entries to num . Valid values for num are 1
or 2. The default number of domain table entries is 2. You can use this
pragma to trade EEPROM space for a domain table entry (see Chapter 8,
Memory Management, of the Neuron C Programmer’s Guide ).
This directive is not supported in model files.
#pragma one_domain
Sets the number of domain table entries to 1. This pragma is provided for
legacy application support and should no longer be used. New applications
should use the num_domain_entries pragma instead. The default number of
domain table entries is 2.
This directive is not supported in model files.
#pragma optimization level
This pragma allows you to specify a code optimization level for optimal use of
device memory. Supported levels are 0 (no optimization) to 5 (maximum
optimization).
When you specify no optimization, the Neuron C compiler attempts to create
fairly economical code. However, some improvements are generally possible,
and sometimes necessary. In addition to specifying additional code
optimization using this directive, consider manual optimization, as described
in the What to Try When a Program Does Not Fit on a Neuron Chip section of
Chapter 8 in the Neuron C Programmer’s Guide .
With optimization enabled, the Neuron C compiler performs several types of
code optimization. For example, it identifies common sub-expressions and
moves them into sub-routines when economical, thus reducing the memory
footprint of the generated code.
Table 5 lists the levels of optimization. Levels 2, 3, 4, and 5 are ignored if you
disable optimation within the NodeBuilder FX Development Tool (select the
Disable optimizer checkbox from the Compiler tab of the NodeBuilder Device
Template Target Properties dialog). Levels 0 and 1 are ignored if you enable
optimation within the NodeBuilder FX Development Tool (clear the Disable
optimizer checkbox).
Table 5. Optimization Levels for the #pragma optimization Directive
Level Optimization Performed Notes
0 No optimization
CP templates are not compressed