Echelon Neuron - Manual (Page 90)

82 Neuron C Compiler Errors (NCC)
NCC# Description
264 The fastaccess feature only applies to arrays [NCC#264]
The optional fastaccess feature should only be used in declarations of array
variable types. The feature does not apply to the indexing operator applied
to pointers.
265
266
267
The stack frame of this procedure is too large (>200 bytes) [NCC#265]
The stack frame of this procedure exceeds 100 bytes [NCC#266]
The stack frame of this procedure exceeds 7 bytes [NCC#267]
On Neuron Chips, references to variables near the top of the stack use the
most efficient instructions. The further down in the stack one goes, the less
efficient the instructions become. This inefficiency affects both the code
size and the code performance. A stack frame larger than seven bytes
begins to incur this penalty. The stack frame includes the parameters and
the local variables.
Neuron Chips do not have very large memory areas set aside for stacks.
Procedures whose stack frame exceed 200 bytes would fail to work;
therefore, this is a compile-time error. Procedures with stack frames in
excess of 100 bytes are flagged with a special warning message because
they use more than half of the stack resources, and nesting these functions
would cause a stack overflow. The compiler does not specifically check for
nesting, but it attempts to use this warning to catch large procedures.
Note that the Neuron chip’s hardware architecture suggests preferring a
large number of small functions over fewer, but larger, functions. Smaller
functions typically lead to much smaller stack frames for each function,
which also allows for more efficient code and thus results in a smaller code
footprint.
See Chapter 8 of the
Neuron C Programmer’s Guide for more information
on managing memory resources.
268 Recommend use of an unqualified 'msg_arrives' event [NCC#268]
A program which receives explicit messages through the msg_arrives event
will be given all such messages which come into the device, whether their
message codes are expected or not. Any unexpected messages must be
handled by the program through a "catch-all" unqualified msg_arrives
event, otherwise such messages will get stuck at the head of the message
queue. See the chapter on messages in the Neuron C Programmer's Guide
for more information on processing incoming messages.