Compiler optimization control
Posted: 12 Feb 2009 20:08
The mikroC for dsPIC compiler does some unused variable optimization in that if it thinks that a variable has been declared but unused, it will actually not compile for it. However, this can sometimes create problems. For example, take the following:-
unsigned char buffer;
void main(void)
{
asm {
mov _buffer, W0
inc W0, W0
mov W0, _buffer
}
while (1);
}
This is going to compile to an error because the pre-processor does not see the reference to the buffer variable in the asm block and so it will not compile for it. As such you will get a linking error which can be a little confusing because it doesn't really tell you what happened. When you look at the code, you cannot find anything wrong. To make this work right now, I have to include an explicit reference to the variable somewhere in the code in the non-asm section.
Is it possible to address this type of problems in the new compiler, or to have the option to turn off some optimizations?
Daniel
unsigned char buffer;
void main(void)
{
asm {
mov _buffer, W0
inc W0, W0
mov W0, _buffer
}
while (1);
}
This is going to compile to an error because the pre-processor does not see the reference to the buffer variable in the asm block and so it will not compile for it. As such you will get a linking error which can be a little confusing because it doesn't really tell you what happened. When you look at the code, you cannot find anything wrong. To make this work right now, I have to include an explicit reference to the variable somewhere in the code in the non-asm section.
Is it possible to address this type of problems in the new compiler, or to have the option to turn off some optimizations?
Daniel