Ok David,
Thank you and sorry,
I will studie the specific documentation.
I have made the modification in my sources and it is ok.
Thank You
Bernard
________________________________________________________________________________________________________
David Brown a écrit:
Hi Bernard,
This is a mistake many people make when they are new to embedded
development, or new to using an optomising C compiler for embedded
development. The code snippet "int x = 1; while (x) ; " tells the compiler
to enter an infinite loop. You've already told the compiler what value "x"
has - why should it bother re-reading it all the time? That's what
optomisation is for - being smart and saving the processor some effort.
What you need to do is declare your variable to be "volatile" - that tells
the compiler the you really do want it to read the memory each loop.
This is all explained in the documentation for the compiler - see
http://mspgcc.sourceforge.net/doc_appendixE.html . You really should read
through the documentation there before posting such questions, and even then
it's polite to phrase your posts in the manner of "What I am I doing wrong"
rather than "Perhaps there's a bug in the compiler" unless you are pretty
confident that this is the case.
And don't post in html - use plain text.
mvh.
David
----- Original Message -----
From: Bernard MONDAN
To: mspgcc-users@lists.sourceforge.net
Sent: Thursday, December 12, 2002 3:31 PM
Subject: [Mspgcc-users] Perhaps a MSP GCC bug ??
Hi dmitry
I think I have found a problem with the compiler.
This is a shortcut to the problem :
I have an interger that is set by a function, decremented by another (under
interrupt) and tested by a third.
I have tested this code :
int xxxx;
xxxx = 4;
while( xxxx )
;
the generated code is :
xxxx = 4;
d8fa: 2f 42 mov #4, r15 ;subst r2 with
As==10
d8fc: a2 42 7c 02 mov #4, &0x027c ;subst r2 with
As==10
while(xxxx)
d900: 0f 93 cmp #0, r15 ;subst r3 with
As==00
d902: fe 23 jnz $-2 ;abs dst addr 0xd900
;
I think that at the address d902 the right code is jnz $-4 and not jnz $-2
beacause the others routines modifie the 0x027c address and not the r15
register.
Please keep me informed about that.
Thank you
Bernard MONDAN
HOMERIDER SYSTEMS
bernard.mon...@homeridersystems.com
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