LCOM1920-T02G10

#ifndef STACK_FRAME_H

#define STACK_FRAME_H

#include <sys/types.h>

typedef unsigned reg_t;         /* machine register */

typedef reg_t segdesc_t;

/* The stack frame layout is determined by the software, but for efficiency

 * it is laid out so the assembly code to use it is as simple as possible.

 * 80286 protected mode and all real modes use the same frame, built with

 * 16-bit registers.  Real mode lacks an automatic stack switch, so little

 * is lost by using the 286 frame for it.  The 386 frame differs only in

 * having 32-bit registers and more segment registers.  The same names are

 * used for the larger registers to avoid differences in the code.

 */

struct stackframe_s {

        u16_t gs;                     /* last item pushed by save */

        u16_t fs;                     /*  ^ */

        u16_t es;                     /*  | */

        u16_t ds;                     /*  | */

        reg_t di;                     /* di through cx are not accessed in C */

        reg_t si;                     /* order is to match pusha/popa */

        reg_t fp;                     /* bp */

/*        reg_t st; */                     /* hole for another copy of sp */

        reg_t bx;                     /*  | */

        reg_t dx;                     /*  | */

        reg_t cx;                     /*  | */

        reg_t retreg;                 /* ax and above are all pushed by save */

/*        reg_t retadr; */                 /* return address for assembly code save() */

        reg_t pc;                     /*  ^  last item pushed by interrupt */

        reg_t cs;                     /*  | */

        reg_t psw;                    /*  | */

        reg_t sp;                     /*  | */

        reg_t ss;                     /* these are pushed by CPU during interrupt */

};

#endif /* #ifndef STACK_FRAME_H */