gnupic: function pointers? (was Re: [gnupic] Relocation problems with gplink)
Subject:
function pointers? (was Re: [gnupic] Relocation problems with gplink)
From:
Iain Dooley ####@####.####
Date:
21 May 2005 03:44:59 +0100
Message-Id: <428F2F87.8090209@iaindooley.com>
Peter Onion wrote:
> [...]
>
> asciitab CODE 0x1C00
> ASCIITable
> DW ASCIInul ; 0x00
> DW ASCIIsoh ; 0x01
> DW ASCIIstx ; 0x02
> DW ASCIIetx ; 0x03
> DW ASCIIeot ; 0x04
this is unrelated to your original issue, but how would you go about then calling these functions? a little while ago, i tried to create a function jump table using calculated goto statements, but failed for some reason and then gave up and did it some other way!!
what i really want to be able to do is have a function table like you have, and then, depending on some variable, execute a function as in the following example (i've marked the part that i'm unsure of!!):
;want to use the idata_init function from another file that does a series of table reads to initialise data from the
;_cinit table
extern idata_init
;my reset vector
_RESET_VECTOR code 0x00
goto init
;some initiliased data
idata
function_table db functionName1,functionName2,functionName3,functionName4
count db 0x03
;my code block
code
init:
;initialise idata using _cinit table generated by the linker
call idata_init
loop:
;load the value of the function table into fsr
lfsr FSR0,function_table
;load the count into WREG
movf count,W
;execute the function using PLUSW0
movff PLUSW0,PCL ;??????? THIS IS THE STEP THAT I'M NOT SURE OF!!!
;have we executed all our functions?
decfsz count
;nope, go and do it again
bra loop
;yep, finish the program
end
