cpik C compiler for PIC c -18 devices Version 0.6.0 - PiKdev, An IDE ...

{
}
int k ;
PREPARE_ROM_ACCESS ; READ_ROMWORD ;
for( k = prodl ; k ; --k)
{
READ_ROMWORD ;
outdec(prodhl) ; putchar(’ ’ ) ;
}
FINISH_ROM_ACCESS ;
This function is very simple to use:
RIputwords("3, 1000, 2000, 3000") ;
Please note that despite the parameter of RIputwords() is a literal, the data really stored in ROM
are words (not a string of chars).
7.7.3 Passing ROM data to a subroutine with a pointer to ROM
In the previous section, blocks of data in ROM were anonymous.
The ROM_ENTRY() macro allows to attach an identifier to a location in ROM as following:
ROM_ENTRY(hello)
{
ROM_TXT("hello guys !\0") ;
}
The hello identifier has the type ROMptr and can be passed to any routine recieving this kind
of pointer. For example, the void lcd_Rputs(ROMptr) ; (from the LCD library) allows such an
usage.
void f()
{
lcd_Rputs(hello) ; // displays ≪hello guy !≫
}
As previously, it is easy to write such a code at C level. For that purpose, the rom.h header
provides a macro ROM_POINTER that allows to declare that a ROMptr will be used to access ROM.
For example, suppose we want to implement a new version of puts() that access the character to
be printed from a ROM pointer.
void Rputs(ROMptr p)
{
ROM_POINTER(p) ;
READ_ROMBYTE ;
while( prodl )
{
putchar( prodl ) ; READ_ROMBYTE ;
}
}
Not really complex, isn’t it ? But the next way to access ROM is even more simple, and more
powerful.
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