/****************************************************************/
/* */
/* pcb.h */
/* */
/* Process Control and Interrupt data structures */
/* */
/* November 26, 1991 */
/* */
/* Copyright (c) 1995 */
/* Pasquale J. Villani */
/* All Rights Reserved */
/* */
/* This file is part of DOS-C. */
/* */
/* DOS-C is free software; you can redistribute it and/or */
/* modify it under the terms of the GNU General Public License */
/* as published by the Free Software Foundation; either version */
/* 2, or (at your option) any later version. */
/* */
/* DOS-C is distributed in the hope that it will be useful, but */
/* WITHOUT ANY WARRANTY; without even the implied warranty of */
/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See */
/* the GNU General Public License for more details. */
/* */
/* You should have received a copy of the GNU General Public */
/* License along with DOS-C; see the file COPYING. If not, */
/* write to the Free Software Foundation, 675 Mass Ave, */
/* Cambridge, MA 02139, USA. */
/****************************************************************/
/***************************************************************
2000/03/22 ska
There is a newly documented (though used previously) side effect
of the definitions and assumptions made herein:
The assembly sources may use a macro named "PUSH$ALL" to push
all processor registers onto the stack, see example below:
PUSH$ALL
mov ax, sp
...
push ax
call _c_function
pop cx
The stack pointer immediately after the PUSH$ALL macro shall point to
a structure used as an "iregs" structure within the C language.
Therefore the internal of the structure "iregs" _must_ always
match the implementation of the macro "PUSH$ALL".
*/
#ifndef __PCB_H
#define __PCB_H
#ifdef MAIN
#ifdef VERSION_STRINGS
static BYTE *pcb_hRcsId =
"$Id: pcb.h 1316 2007-05-15 17:48:47Z bartoldeman $";
#endif
#endif
/* Force one-byte alignment for all the internal structures, see above */
#include <algnbyte.h>
/* */
/* interrupt handler structure definition */
/* */
typedef union {
UWORD x; /* access mode for ax, bx, etc. */
struct {
UBYTE l; /* access mode for al, bl, etc. */
UBYTE h; /* access mode for ah, bh, etc. */
} b;
} xreg;
/* The structure assumes that:
1) An interrupt was invoked, &
2) the PUSH$ALL macro was invoked immediately after that.
Furthermore, the PUSH$ALL macro must push ES first and AX last.
-- 2000/03/22 ska*/
/* maps MS-DOS unique stacking order */
typedef struct _iregss {
xreg a, b, c, d;
UWORD si, di, bp, ds, es;
UWORD ip, cs, flags;
} iregs;
/* struct used for local copy of registers */
typedef struct {
xreg a, b, c, d;
UWORD si, di, ds, es;
} lregs;
/* Process control block for task switching */
typedef struct {
UWORD pc_ss;
UWORD pc_sp;
iregs pc_regs;
} pcb;
/* Note: The following figure is not made by myself and I assume that
the order of "ES" through "AX" are misinterpreted?! -- 2000/03/22 ska*/
/* For MSC, the following offsets must match the assembly process */
/* support offsets */
/* NOTE: Alignemnts must be set to 1 (-Zp1) */
/* ss: 0 */
/* sp: 2 */
/* es: 4 */
/* ds: 6 */
/* di: 8 */
/* si: 10 */
/* bp: 12 */
/* sp: 14 NOTE: not used in this structure */
/* bx: 16 */
/* dx: 18 */
/* cx: 20 */
/* ax: 22 */
/* ip: 24 */
/* cs: 26 */
/* flags: 28 */
/* */
/* For Borland C, the following offsets must match the assembly process */
/* support offsets */
/* ss: 0 */
/* sp: 2 */
/* bp: 4 */
/* di: 6 */
/* si: 8 */
/* ds: 10 */
/* es: 12 */
/* dx: 14 */
/* cx: 16 */
/* bx: 18 */
/* ax: 20 */
/* ip: 22 */
/* cs: 24 */
/* flags: 26 */
#define BP bp
#define DI di
#define SI si
#define DS ds
#define ES es
#define DX d.x
#define CX c.x
#define BX b.x
#define AX a.x
#define DH d.b.h
#define CH c.b.h
#define BH b.b.h
#define AH a.b.h
#define DL d.b.l
#define CL c.b.l
#define BL b.b.l
#define AL a.b.l
#define IP ip
#define CS cs
#define FLAGS flags
#define FLG_ZERO 0x0040
#define FLG_CARRY 0x0001
/* Allow default alignment from now on */
#include <algndflt.h>
#endif