Preprocessor gurus help requested!

 Preprocessor gurus help requested!

Hello preprocessor masters/gurus,

I am trying to make a piece of software as easily configurable as possible, by only indicting which port/pin combination controls the hardware:

// SPI master/slave arbitration
#define SPI_MASTER_IO_PORT                      0
#define SPI_MASTER_IO_PIN                       19

#define FIO_PORT_PIN(x)                         FIO##x##PIN

#define SPI_MASTER_REQUEST_IO_BIT_STATUS          ( (FIO_PORT_PIN(SPI_MASTER_IO_PORT)>>SPI_MASTER_IO_PIN)&1)

The result I want is this:

((FIO0PIN>>19)&1)

but this yields the following error message:

..\src\spi.c(341): error:  #20: identifier "FIOSPI_MASTER_IO_PORTCLR" is undefined</ptr>

Are there ways around the apparent failure of the double replacement required here...?

Thanks in advance

 RE: Preprocessor gurus help requested!

Ah, it is good to have colleagues and the internet/google! here is the solution:

#define FIO_PORT_PIN_TEMP(x)                               FIO##x##PIN
#define FIO_PORT_PIN(x)                         FIO_PORT_PIN_TEMP(x)

logic:

Macros that call other macros that stringify or concatenate.
If an argument is stringified or concatenated, the prescan does not occur. If you want to expand a macro, then stringify or concatenate its expansion, you can do that by causing one macro to call another macro that does the stringification or concatenation. For instance, if you have
          #define AFTERX(x) X_ ## x
          #define XAFTERX(x) AFTERX(x)
          #define TABLESIZE 1024
          #define BUFSIZE TABLESIZE

then AFTERX(BUFSIZE) expands to X_BUFSIZE, and XAFTERX(BUFSIZE) expands to X_1024. (Not to X_TABLESIZE. Prescan always does a complete expansion.)

 RE: Preprocessor gurus help requested!

So the final macros look like this:

// SPI master/slave arbitration
#define SPI_MASTER_IO_PORT                      0
#define SPI_MASTER_IO_PIN                       19

#define SPI_MASTER_DISPLAY_PORT         0
#define SPI_MASTER_DISPLAY_PIN          5

#define FIO_PORT_PIN_TEMP(x)            FIO##x##PIN
#define FIO_PORT_PIN(x)                         FIO_PORT_PIN_TEMP(x)
#define FIO_PORT_CLR_TEMP(x)            FIO##x##CLR
#define FIO_PORT_CLR(x)                         FIO_PORT_CLR_TEMP(x)
#define FIO_PORT_SET_TEMP(x)            FIO##x##SET
#define FIO_PORT_SET(x)                         FIO_PORT_SET_TEMP(x)

#define SPI_MASTER_REQUEST_IO_IS_MASTER                   ( ( (FIO_PORT_PIN(SPI_MASTER_IO_PORT)>>SPI_MASTER_IO_PIN)&1) == 0)
#define SPI_MASTER_REQUEST_IO_NOT_MASTER                  ( ( (FIO_PORT_PIN(SPI_MASTER_IO_PORT)>>SPI_MASTER_IO_PIN)&1) == 1)
#define SPI_MASTER_REQUEST_IO_BIT_SET                     FIO_PORT_CLR(SPI_MASTER_IO_PORT) |= (1<<SPI_MASTER_IO_PIN) ;
#define SPI_MASTER_REQUEST_IO_BIT_RESET                   FIO_PORT_SET(SPI_MASTER_IO_PORT) |= (1<<SPI_MASTER_IO_PIN) ;

#define SPI_MASTER_REQUEST_DISPLAY_BIT_IS_MASTER  ( ( (FIO_PORT_PIN(SPI_MASTER_DISPLAY_PORT)>>SPI_MASTER_DISPLAY_PIN)&1) == 0)
#define SPI_MASTER_REQUEST_DISPLAY_BIT_NOT_MASTER ( ( (FIO_PORT_PIN(SPI_MASTER_DISPLAY_PORT)>>SPI_MASTER_DISPLAY_PIN)&1) == 1)
#define SPI_MASTER_REQUEST_DISPLAY_BIT_SET        FIO_PORT_CLR(SPI_MASTER_DISPLAY_PORT) |= (1<<SPI_MASTER_DISPLAY_PIN) ;
#define SPI_MASTER_REQUEST_DISPLAY_BIT_RESET      FIO_PORT_SET(SPI_MASTER_DISPLAY_PORT) |= (1<<SPI_MASTER_DISPLAY_PIN) ;