gnupic: Thread: SDCC Pic port now supports object files

Craig Franklin has made tremendous progress with gputils adding 
compatibility with Microchip's MPLINK. This means that gpasm supports 
relocatable .asm files and that there's a gplink to take advantage of 
linking object files together. Craig also started a patch to SDCC that 
introduced object files to the PIC Port of SDCC. I finished it up and have 
got it to the point that all of the PIC regression tests pass.

Here's a really quick summary of how to generate a .hex file now:

1) Install the latest version of gputils and SDCC

2) Create your source. Here's one called test.c:

#define __16F873
#include "p16f873.h"

typedef unsigned int word;
word at 0x2007  CONFIG = _WDT_OFF & _PWRTE_ON;

void main()
{
}

3) compile the source

$ sdcc -mpic14 -c -pp16f873 test.c

the -m option selects the PIC port of SDCC
the -c means compile only, but don't assemble or link
the -p option selects a particular processor in the pic port

This will create several files:

$ ls test.*
test.asm  test.c  test.d  test.lst  test.o  test.p

The .o file is the only important one. The .asm file is what's created by 
sdcc. However, sdcc automatically invokes gpasm to create a .o and .lst 
file. (The .d and .p files are debug files). If you want, you can 
re-assemble the .asm file to re-create the .o and .lst files.


4) Link the source. In a few days (or maybe even now?) sdcc will support 
several .o files. But for the time being the .hex and .cod files are 
created by:

$ gplink --map -c -s 16f873.lkr -o test.o test.o

The file 16f873.lkr is part of the gputils package. (You'll either need to 
copy it to the same directory as your source or you'll need to specify the 
path to it.) 

The --map options tells gplink to output a .map file. This shows the 
absolute address and types of all objects.
The -c option specifies that an executable (.hex) file should be produced.
The -s 16f873.lkr selects the linker script (which is processor 
dependent).
The -o test.o says that gplink should produce an alternate output file. 
Without this option, gplink will produce files named a.map, a.cod, and 
a.hex. 


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Again, this is just a quick summary. Expect more enhancements soon!

Scott