usr/src/sys/i386/include/reg.h

/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * William Jolitz.
 *
 * %sccs.include.redist.c%
 *
 *      @(#)reg.h       5.5 (Berkeley) %G%
 */

/*
 * Location of the users' stored
 * registers within appropriate frame of 'trap' and 'syscall', relative to
 * base of stack frame.
 * Normal usage is u.u_ar0[XX] in kernel.
 */

/* When referenced during a trap/exception, registers are at these offsets */

#define tES     (0)
#define tDS     (1)
#define tEDI    (2)
#define tESI    (3)
#define tEBP    (4)

#define tEBX    (6)
#define tEDX    (7)
#define tECX    (8)
#define tEAX    (9)

#define tEIP    (12)
#define tCS     (13)
#define tEFLAGS (14)
#define tESP    (15)
#define tSS     (16)

/* During a system call, registers are at these offsets instead of above. */

#define sEDI    (0)
#define sESI    (1)
#define sEBP    (2)

#define sEBX    (4)
#define sEDX    (5)
#define sECX    (6)
#define sEAX    (7)
#define sEFLAGS (8)
#define sEIP    (9)
#define sCS     (10)
#define sESP    (11)
#define sSS     (12)

#define PC      sEIP
#define SP      sESP
#define PS      sEFLAGS
#define R0      sEDX
#define R1      sECX
/*
 * Registers accessible to ptrace(2) syscall for debugger
 */
#ifdef IPCREG
#define NIPCREG 14
int ipcreg[NIPCREG] =
  { tES,tDS,tEDI,tESI,tEBP,tEBX,tEDX,tECX,tEAX,tEIP,tCS,tEFLAGS,tESP,tSS };
#endif