usr/src/grub/grub-0.97/netboot/segoff.h

   1 /*
   2  * Segment:offset types and macros
   3  *
   4  * Initially written by Michael Brown (mcb30).
   5  */
   6
   7 #ifndef SEGOFF_H
   8 #define SEGOFF_H
   9
  10 #include <stdint.h>
  11 #include <io.h>
  12
  13 /* Segment:offset structure.  Note that the order within the structure
  14  * is offset:segment.
  15  */
  16 typedef struct {
  17         uint16_t offset;
  18         uint16_t segment;
  19 } segoff_t;
  20
  21 /* For PXE stuff */
  22 typedef segoff_t SEGOFF16_t;
  23
  24 /* Macros for converting from virtual to segment:offset addresses,
  25  * when we don't actually care which of the many isomorphic results we
  26  * get.
  27  */
  28 #ifdef DEBUG_SEGMENT
  29 uint16_t SEGMENT ( const void * const ptr ) {
  30         uint32_t phys = virt_to_phys ( ptr );
  31         if ( phys > 0xfffff ) {
  32                 printf ( "FATAL ERROR: segment address out of range\n" );
  33         }
  34         return phys >> 4;
  35 }
  36 #else
  37 #define SEGMENT(x) ( virt_to_phys ( x ) >> 4 )
  38 #endif
  39 #define OFFSET(x) ( virt_to_phys ( x ) & 0xf )
  40 #define SEGOFF(x) { OFFSET(x), SEGMENT(x) }
  41 #define VIRTUAL(x,y) ( phys_to_virt ( ( ( x ) << 4 ) + ( y ) ) )
  42
  43 #endif /* SEGOFF_H */