/*
* Memory and machine-specific definitions.  Used in C and assembler.
*/

/*
* Sizes
*/
#define BI2BY           8                       /* bits per byte */
#define BI2WD           32                      /* bits per word */
#define BY2WD           4                       /* bytes per word */
#define BY2PG           4096                    /* bytes per page */
#define WD2PG           (BY2PG/BY2WD)           /* words per page */
#define PGSHIFT         12                      /* log(BY2PG) */
#define PGROUND(s)      (((s)+(BY2PG-1))&~(BY2PG-1))

/*
* Fundamental addresses
*/
#define CONFADDR        0x1200          /* info passed from boot loader */
#define BIOSXCHG        0x6000          /* To exchange data with the BIOS */

#define SELGDT  (0<<3)  /* selector is in gdt */
#define SELLDT  (1<<3)  /* selector is in ldt */

#define SELECTOR(i, t, p)       (((i)<<3) | (t) | (p))

/*
*  fields in segment descriptors
*/
#define SEGDATA (0x10<<8)       /* data/stack segment */
#define SEGEXEC (0x18<<8)       /* executable segment */
#define SEGTSS  (0x9<<8)        /* TSS segment */
#define SEGCG   (0x0C<<8)       /* call gate */
#define SEGIG   (0x0E<<8)       /* interrupt gate */
#define SEGTG   (0x0F<<8)       /* task gate */
#define SEGTYPE (0x1F<<8)

#define SEGP    (1<<15)         /* segment present */
#define SEGPL(x) ((x)<<13)      /* priority level */
#define SEGB    (1<<22)         /* granularity 1==4k (for expand-down) */
#define SEGG    (1<<23)         /* granularity 1==4k (for other) */
#define SEGE    (1<<10)         /* expand down */
#define SEGW    (1<<9)          /* writable (for data/stack) */
#define SEGR    (1<<9)          /* readable (for code) */
#define SEGD    (1<<22)         /* default 1==32bit (for code) */

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