usr/src/sys/pmax/stand/start.s

/*
 * Copyright (c) 1992 Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Ralph Campbell.
 *
 * %sccs.include.redist.c%
 *
 *      @(#)start.s     7.1 (Berkeley) %G%
 *
 * start.s -
 *
 *     Contains code that is the first executed at boot time.
 *
 *      Copyright (C) 1989 Digital Equipment Corporation.
 *      Permission to use, copy, modify, and distribute this software and
 *      its documentation for any purpose and without fee is hereby granted,
 *      provided that the above copyright notice appears in all copies.
 *      Digital Equipment Corporation makes no representations about the
 *      suitability of this software for any purpose.  It is provided "as is"
 *      without express or implied warranty.
 *
 * from: $Header: /sprite/src/boot/decprom/ds3100.md/RCS/start.s,
 *      v 1.1 90/02/16 16:19:39 shirriff Exp $ SPRITE (DECWRL)
 */

#include <regdef.h>
#include "../include/machConst.h"

/*
 * Amount to take off of the stack for the benefit of the debugger.
 */
#define START_FRAME     ((4 * 4) + 4 + 4)
#define Init    0xbfc00018

    .globl      start
start:
    .set noreorder
    mtc0        zero, MACH_COP_0_STATUS_REG     # Disable interrupts
    li          sp, MACH_CODE_START - START_FRAME
    la          gp, _gp
    sw          zero, START_FRAME - 4(sp)       # Zero out old ra for debugger
    sw          zero, START_FRAME - 8(sp)       # Zero out old fp for debugger
    jal         main                            # main(argc, argv, envp)
    nop
    li          a0, Init                        # done, so call prom
    j           a0

    .globl      Boot_Transfer
Boot_Transfer:
    mtc0        zero, MACH_COP_0_STATUS_REG     # Disable interrupts
    li          sp, MACH_CODE_START - START_FRAME
    la          gp, _gp
    sw          zero, START_FRAME - 4(sp)       # Zero out old ra for debugger
    sw          zero, START_FRAME - 8(sp)       # Zero out old fp for debugger
    jal         a3                              # Jump to routine
    nop