1 /* 2 * Memory and machine-specific definitions. Used in C and assembler. 3 */ 4 5 /* 6 * Sizes 7 */ 8 #define BI2BY 8 /* bits per byte */ 9 #define BI2WD 32 /* bits per word */ 10 #define BY2WD 4 /* bytes per word */ 11 #define BY2PG 4096 /* bytes per page */ 12 #define WD2PG (BY2PG/BY2WD) /* words per page */ 13 #define PGSHIFT 12 /* log(BY2PG) */ 14 #define PGROUND(s) (((s)+(BY2PG-1))&~(BY2PG-1)) 15 16 /* 17 * Fundamental addresses 18 */ 19 #define CONFADDR 0x1200 /* info passed from boot loader */ 20 #define BIOSXCHG 0x6000 /* To exchange data with the BIOS */ 21 22 #define SELGDT (0<<3) /* selector is in gdt */ 23 #define SELLDT (1<<3) /* selector is in ldt */ 24 25 #define SELECTOR(i, t, p) (((i)<<3) | (t) | (p)) 26 27 /* 28 * fields in segment descriptors 29 */ 30 #define SEGDATA (0x10<<8) /* data/stack segment */ 31 #define SEGEXEC (0x18<<8) /* executable segment */ 32 #define SEGTSS (0x9<<8) /* TSS segment */ 33 #define SEGCG (0x0C<<8) /* call gate */ 34 #define SEGIG (0x0E<<8) /* interrupt gate */ 35 #define SEGTG (0x0F<<8) /* trap gate */ 36 #define SEGLDT (0x02<<8) /* local descriptor table */ 37 #define SEGTYPE (0x1F<<8) 38 39 #define SEGP (1<<15) /* segment present */ 40 #define SEGPL(x) ((x)<<13) /* priority level */ 41 #define SEGB (1<<22) /* granularity 1==4k (for expand-down) */ 42 #define SEGD (1<<22) /* default 1==32bit (for code) */ 43 #define SEGE (1<<10) /* expand down */ 44 #define SEGW (1<<9) /* writable (for data/stack) */ 45 #define SEGR (1<<9) /* readable (for code) */ 46 #define SEGL (1<<21) /* 64 bit */ 47 #define SEGG (1<<23) /* granularity 1==4k (for other) */ 48