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RE: [avr-chat] Strange struct problem
From: |
Larry Barello |
Subject: |
RE: [avr-chat] Strange struct problem |
Date: |
Thu, 8 Dec 2005 17:23:54 -0800 |
Oh, I forgot to add: if automatics cannot fit into registers they go onto a
stack frame... Some might assume all automatics go onto the frame but GCC
doesn't.
Cheers!
-----------
Larry Barello
www.barello.net
| -----Original Message-----
| From: address@hidden [mailto:avr-chat-
| address@hidden On Behalf Of Larry Barello
| Sent: Thursday, December 08, 2005 5:06 PM
| To: address@hidden; address@hidden
| Subject: RE: [avr-chat] Strange struct problem
|
| You are declaring the data as automatic. GCC is very clever and puts
| automatic variables into registers unless you either a) take an address of
| them, b) declare too many (or too big) or c) set optimization low.
|
| I ran across this with a boot loader I was writing. I wanted to save a 24
| bit address in a struct (rampz + address) and the resulting code was
| seriously broken (actually, the compiler would crash). In short, your
| automatic variables that are structs or unions need to fit into one of the
| normal sizes: byte, word, long, or double long.
|
| When they do fit, spectacular code will be generated.
|
| -----------
| Larry Barello
| www.barello.net
|
- [avr-chat] Strange struct problem, Daniel O'Connor, 2005/12/08
- Re: [avr-chat] Strange struct problem, Daniel O'Connor, 2005/12/08
- Re: [avr-chat] Strange struct problem, Russell Shaw, 2005/12/08
- Re: [avr-chat] Strange struct problem, Daniel O'Connor, 2005/12/08
- RE: [avr-chat] Strange struct problem, Larry Barello, 2005/12/08
- RE: [avr-chat] Strange struct problem,
Larry Barello <=
- Re: [avr-chat] Strange struct problem, Russell Shaw, 2005/12/08
- Re: [avr-chat] Strange struct problem, Daniel O'Connor, 2005/12/08
- RE: [avr-chat] Strange struct problem, Larry Barello, 2005/12/08
- Re: [avr-chat] Strange struct problem, Daniel O'Connor, 2005/12/08
- Re: [avr-chat] Strange struct problem, Ian Caddy, 2005/12/09
- Re: [avr-chat] Strange struct problem, Daniel O'Connor, 2005/12/09
- Re: [avr-chat] Strange struct problem, Eric Weddington, 2005/12/09
- Re: [avr-chat] Strange struct problem, Joerg Wunsch, 2005/12/09
- Re: [avr-chat] Strange struct problem, Daniel O'Connor, 2005/12/09
- RE: [avr-chat] Strange struct problem, Larry Barello, 2005/12/09