// testing some more complicated defines

#define spi_enable(mask)        \
        lda SPISSRB             :\
        and #255-(mask)         :\
        sta SPISSRB

#define spi_disable(mask)       \
        lda SPISSRB             :\
        ora #(mask)             :\
        sta SPISSRB

#define spi_wra()               \
        .(                      :\
        sta SPIDR               :\
l_      bit SPISR               :\
        bpl l_                  :\
        lda SPIDR               :\
        .)

#define max3420e_enable()       \
        spi_enable(MAX3420E_EnMask)

#define max3420e_disable()      \
        spi_disable(MAX3420E_EnMask)

#define wrac(reg)               \
        pha                     :\
        max3420e_enable()       :\
        lda #(reg) | 0x02       :\
        spi_wra()               :\
        pla                     :\
        spi_wra()               :\
        max3420e_disable()

// just the definition of this macro hangs the xa indefinitely...

#define CLRBIT(reg, val)        \
        rreg(reg)               :\
        and #255-val            :\
        wrac(reg)