63 lines
2.3 KiB
C
63 lines
2.3 KiB
C
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#ifndef _I386_TYPES_H
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#define _I386_TYPES_H
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#include <minix/sys_config.h>
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#include "archconst.h"
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typedef unsigned reg_t; /* machine register */
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typedef reg_t segdesc_t;
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/* The stack frame layout is determined by the software, but for efficiency
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* it is laid out so the assembly code to use it is as simple as possible.
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* 80286 protected mode and all real modes use the same frame, built with
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* 16-bit registers. Real mode lacks an automatic stack switch, so little
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* is lost by using the 286 frame for it. The 386 frame differs only in
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* having 32-bit registers and more segment registers. The same names are
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* used for the larger registers to avoid differences in the code.
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*/
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struct stackframe_s { /* proc_ptr points here */
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u16_t gs; /* last item pushed by save */
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u16_t fs; /* ^ */
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u16_t es; /* | */
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u16_t ds; /* | */
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reg_t di; /* di through cx are not accessed in C */
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reg_t si; /* order is to match pusha/popa */
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reg_t fp; /* bp */
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reg_t st; /* hole for another copy of sp */
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reg_t bx; /* | */
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reg_t dx; /* | */
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reg_t cx; /* | */
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reg_t retreg; /* ax and above are all pushed by save */
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reg_t retadr; /* return address for assembly code save() */
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reg_t pc; /* ^ last item pushed by interrupt */
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reg_t cs; /* | */
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reg_t psw; /* | */
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reg_t sp; /* | */
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reg_t ss; /* these are pushed by CPU during interrupt */
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};
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struct segdesc_s { /* segment descriptor for protected mode */
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u16_t limit_low;
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u16_t base_low;
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u8_t base_middle;
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u8_t access; /* |P|DL|1|X|E|R|A| */
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u8_t granularity; /* |G|X|0|A|LIMT| */
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u8_t base_high;
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};
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#define LDT_SIZE (2 + NR_REMOTE_SEGS) /* CS, DS and remote segments */
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/* Fixed local descriptors. */
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#define CS_LDT_INDEX 0 /* process CS */
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#define DS_LDT_INDEX 1 /* process DS=ES=FS=GS=SS */
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#define EXTRA_LDT_INDEX 2 /* first of the extra LDT entries */
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typedef struct segframe {
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reg_t p_ldt_sel; /* selector in gdt with ldt base and limit */
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struct segdesc_s p_ldt[2+NR_REMOTE_SEGS]; /* CS, DS and remote */
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} segframe_t;
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#endif /* #ifndef _I386_TYPES_H */
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