From: Peter Townson <Peter.Townson@ta...> - 2003-07-15 23:37:05
Just a quick comment regarding the port access methods (or lack there =
of) in the Z80 port of SDCC.
I find Philipp's solution very useful and helpfull, but I wonder if the =
implementations of inp/outp (or inb/outb which ever suits) might not be =
better implemented as built-in functions in the compiler. =20
The mechanism for doing built-in functions seems to be there in the =
files src/z80/main.c and src/z80/gen.c ( function genBuiltIn()) but this =
code does not seem to be used (at all). There seems to be code there =
for built-in strcpy() & memcpy() which may be able to be used (assuming =
it works) and there are definately a number of examples of =
implementation in the 8051 versions of the same file.
An other alternative would be to emulate the use of the special words =
(like xdata etc) and implement a specific 'port' addressing mode with =
usage such as 'port at (0x42) unsigned char CtrlPort;' say. Admittedly =
such a change would required a great deal deeper understanding of the =
SDCC code-base than I currently have.
Anyone else have any other (possibly better) ideas ?