Hi Jim,
that seems to be a promising solution.
If I keep the prefix "_" for a global variable , there is a problem in
accessing it in gdb...let me explain you with an example
Eg: file1.c
int a = 10;
int main()
{
int b =10;
int c;
c = add( a , b);
return 0;
}
file2.c
int add( int x, int y)
{
return x+y ;
}
> mycompiler-gcc -g file1.c file2.c
> mycompiler-gdb a.out
>> when i print "a" in file1.c , i am able to see value 10;
>> when i print "a" int file2.c, it prints , no symbol defined.
Instead I can access it with " print _a"
Thats the problem; guess i am clear this time.
prefixing registers is out of scope for me , as people got used to
register names r0, r1......
Regards,
Sumanth G
Jim Wilson wrote:
On Mon, 2009-08-03 at 09:44 +0530, sumanth wrote:
How can i make sure my tool chain knows the difference between
global variable r0 and register r0.
The simple solution is to either add a prefix to variable names, or to
add a prefix to register names. In ELF, the convention is to not add a
prefix to variables names, we add a prefix to register names instead if
we need one, e.g. %eax on i386, or $4 on mips.
You can of course choose to add a prefix to variable names. It just
isn't the convention. See for instance how the arm-elf port works when
you use the -fleading-underscore option.
A less simple solution is to have an assembler syntax that avoids
ambiguity between register names and variable names. If for instance
you have a move instruction that can accept either a register or a
variable as source, then you have an ambiguity. You could instead have
a load instruction for reading memory, and a move instruction for
reading registers, and then you don't have an ambiguity anymore. You
can also do things with addressing modes and relocation operators to
reduce ambiguities.
Jim
