RE: [avr-chat] Strange struct problem

[Larry Barello]

I dunno.  I built your code (-Os) and loaded the resulting dwarf-2 .elf file
into the simulator and it works just fine.  The struct is initialize
properly and the correct values are passed into the uart_puts_hex() routine.

Maybe your problem is elsewhere?

avr-gcc -g -Wall -Os -std=gnu99 -Wa,-adhlns=testcase.lst -Wstrict-prototypes
-mmcu=atmega32 -gdwarf-2 -c -o testcase.o testcase.c
avr-gcc -Wl -mmcu=atmega32 -dwarf-2 testcase.o -o testcase.elf

Dwarf-2 and Astudio 4.12 is pretty good as a debug environment.

-----------
Larry Barello
www.barello.net


| -----Original Message-----
| From: Daniel O'Connor [mailto:address@hidden
| Sent: Thursday, December 08, 2005 8:45 PM
| To: Larry Barello
| Cc: address@hidden
| Subject: Re: [avr-chat] Strange struct problem
| 
| 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
| GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C