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Re: [avr-gcc-list] First steps with avr-gcc
From: |
Dave Hylands |
Subject: |
Re: [avr-gcc-list] First steps with avr-gcc |
Date: |
Fri, 21 Oct 2005 11:22:23 -0700 |
Hi David,
Sending to the whole list this time.
> My questions:
> - The C code is not complete in the list file. Usually, the next line
> after a '{' is missing. Is there something wrong on my side or should it
> simply be like this?
I normally add a special rule to my makefile to produce list files. I
use the following options:
%.cod : %.c FORCE
$(ECHO) "Listing $< ..."
$(Q)$(COMPILE.c) -gstabs -Wa,-ahdlms=$@ $<
This snippet was from my own makefile that I use for building and
probably isn't entirely compatible with whatever you're using.
> - the function uses 2 registers (16 bits) while it should only use 8 bits.
> Is there something wrong on the make settings I used (generated by AVR
> Studio btw) or something else?
By default, the compiler is setup to use 16 bit ints. The C language
requires that the & operation promote both sides to ints.
Using the -mint8 option will produce smaller code (but only have 8 bit ints).
> - I'm surely lacking some knowledge here, should I first start reading the
> make manual, the gcc one or simply improve my C knowledge?
All of the above :) Information like this is normally buried deep and
often requires connecting multiple tidbits together.
--
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/