This is the first time I'm using macros in C and I'm trying to replace a large section of code that I'd normally place into a function with a macro. This is a part of an interrupt which will be used quite often and therefore I need to optimize it as much as I can. After reading the documentation, I've seen that the compiler doesn't support function inlining and I want to avoid the function call overhead.
The code itself sends data to a serial-in parallel-out shift register and as far as I can see, there's no shorter way to write the piece of code I need.
I'm using C18 compiler version 3.41 and MPLAB X IDE.
So here's the code I'm using in function form:
void first_one(void)
{
//3 invisible zeroes
LATBbits.LATB1=0; //data set to zero
LATBbits.LATB0=1;//first clock
LATBbits.LATB0=0;
LATBbits.LATB0=1;//second clock
LATBbits.LATB0=0;
LATBbits.LATB0=1;//third clock
LATBbits.LATB0=0;
//end of invisible zeroes
//two visible zeroes
LATBbits.LATB0=1;//first clock
LATBbits.LATB0=0;
LATBbits.LATB0=1;//second clock
LATBbits.LATB0=0;
//end of two visible zeroes
LATBbits.LATB1=1;//Data is now one
LATBbits.LATB0=1;
LATBbits.LATB0=0;
//one
LATBbits.LATB1=0;//Data is now zero
LATBbits.LATB0=1;//first clock
LATBbits.LATB0=0;
LATBbits.LATB0=1;//second clock
LATBbits.LATB0=0;
//after this, everything should be in place
LATBbits.LATB0=1;
LATBbits.LATB0=0;
}
I've turned the function into this macro:
#define first_one() { \
\
LATBbits.LATB1=0;\
\
LATBbits.LATB0=1;\
LATBbits.LATB0=0;\
\
LATBbits.LATB0=1;\
LATBbits.LATB0=0;\
\
LATBbits.LATB0=1;\
LATBbits.LATB0=0;\
\
LATBbits.LATB0=1;\
LATBbits.LATB0=0;\
\
LATBbits.LATB0=1;\
LATBbits.LATB0=0;\
\
LATBbits.LATB1=1;\
\
LATBbits.LATB0=1;\
LATBbits.LATB0=0;\
\
LATBbits.LATB1=0;\
^^^ The syntax error is here!
\
LATBbits.LATB0=1;\
LATBbits.LATB0=0;\
\
LATBbits.LATB0=1;\
LATBbits.LATB0=0;\
\
LATBbits.LATB0=1;\
LATBbits.LATB0=0;\
\
}
So what am I doing wrong?
Update: I removed the comments and am now getting a syntax error in a different location.
Check there is no spaces after the \
tokens, some compiler issue a compile error for this.