Re: [avr-chat] Strange struct problem

[Daniel O'Connor]

On Fri, 9 Dec 2005 14:49, Larry Barello wrote:
> Which version of the compiler are you using?  I find it hard to believe
> that something this fundamental (a static array of five chars) would go
> unnoticed until now.

Yeah, me too :)
The .lst file shows buffer and abc are in the data section..

The data section ends up in SRAM, right?

> I took your test case, stripped it down and it appears that GCC does the
> right thing: Because the data is initialized it sticks the struct onto the
> stack then initializes the values.
>
> The version of GCC I am using is 3.4.3 (WinAvr)

[inchoate 15:11] ~ >avr-gcc -v
Reading specs from /usr/local/lib/gcc/avr/3.4.4/specs
Configured with: ./configure --target=avr --disable-nls --prefix=/usr/local 
i386-portbld-freebsd7.0
Thread model: single
gcc version 3.4.4

> Are you using some hacked version of the C runtime, or startup that isn't
> initializing the SRAM data?  Or is it possible you application is > 64k and
> the initialized data segment is beyond the reach of the LPM command (IIRC
> gcc can't access data > 64k, although the code can go that high)

If you take my testcase.c file and do..
avr-gcc -O2 -fno-strict-aliasing -pipe  -g -Wall -Wunreachable-code 
-DF_CPU=16000000 -mmcu=atmega32 -Wa,-adhlmsn=testcase.lst -c testcase.c -o 
testcase.o
avr-gcc -O2 -fno-strict-aliasing -pipe  -g -Wall -Wunreachable-code 
-DF_CPU=16000000 -mmcu=atmega32  -Wl,-Map=testcase.map,--cref  -g testcase.o -o 
testcase.elf 
avr-objcopy -j .text -O ihex testcase.elf testcase.hex
avr-objdump -S testcase.elf > testcase.dmp

You will get the code I am shoving into my micro, which I do with..

avrdude -U flash:w:testcase.hex -p m32 -c alf -E vcc,noreset -q


-- 
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
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