src/include/gpxe/bitbash.h

   1 #ifndef _GPXE_BITBASH_H
   2 #define _GPXE_BITBASH_H
   3
   4 /** @file
   5  *
   6  * Bit-bashing interfaces
   7  *
   8  */
   9
  10 struct bit_basher;
  11
  12 /** Bit-bashing operations */
  13 struct bit_basher_operations {
  14         /**
  15          * Set/clear output bit
  16          *
  17          * @v basher            Bit-bashing interface
  18          * @v bit_id            Bit number
  19          * @v data              Value to write
  20          *
  21          * @c data will be 0 if a logic 0 should be written (i.e. the
  22          * bit should be cleared), or -1UL if a logic 1 should be
  23          * written (i.e. the bit should be set).  This is done so that
  24          * the method may simply binary-AND @c data with the
  25          * appropriate bit mask.
  26          */
  27         void ( * write ) ( struct bit_basher *basher, unsigned int bit_id,
  28                            unsigned long data );
  29         /**
  30          * Read input bit
  31          *
  32          * @v basher            Bit-bashing interface
  33          * @v bit_id            Bit number
  34          * @ret zero            Input is a logic 0
  35          * @ret non-zero        Input is a logic 1
  36          */
  37         int ( * read ) ( struct bit_basher *basher, unsigned int bit_id );
  38 };
  39
  40 /** A bit-bashing interface */
  41 struct bit_basher {
  42         /** Bit-bashing operations */
  43         struct bit_basher_operations *op;
  44 };
  45
  46 extern void write_bit ( struct bit_basher *basher, unsigned int bit_id,
  47                         unsigned long data );
  48 extern int read_bit ( struct bit_basher *basher, unsigned int bit_id );
  49
  50 #endif /* _GPXE_BITBASH_H */