In SX Microcontrollers, SX/B Compiler and SX-Key Tool, peterverkaik wrote:

Jon,

Thanks for the libraries.
As the number of libraries is still small, let me make a suggestion.

You enclose the library code in '{$ifused subname}-'{$endif} blocks
which is good. You have grouped related subroutines in a single library file which is
also good.
Something that may become a problem when the number of libraries grows is the
limited number of SUB declaration that sxb supports, the limit is 128 because 
all declared subs require 2 bytes in the lower half of codepage 0.

Even if you only need TX_STR, the other subroutines still occupy entries
in the subroutine jumptable. If you need to include more libraries as the program grows,
this will quickly fill the jumptable.

The way I resolve this is by using the '{$USES subname} directive
that I place at the top of the main program file, before loading the xxx_DEF.SXB files.
eg. '{$USES TX_STR}
This informes the sxb compiler TX_STR is to be used so it reserves an entry for it.

You then enclose the sub declarations like this:
'{$ifused TX_STR}
TX_STR          SUB     2                       ' transmit a string
'{$endif}

and enclose the subroutine in xxx_INC.SXB likewise:
'{$ifused TX_STR}
SUB TX_STR
ENDSUB

'{$endif}

This saves jumptable entries.
It still is not ideal, but with a single pass compiler probably the best way.


regards peter

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