sys/i386/stand/srt0.c

/*-
 * 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.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      from: @(#)srt0.c        5.3 (Berkeley) 4/28/91
 *      $Id$
 */

/*
 * Startup code for standalone system
 * Non-relocating version -- for programs which are loaded by boot
 * Relocating version for boot
 * Small relocating version for "micro" boot
 */

        .globl  _end
        .globl  _edata
        .globl  _main
        .globl  __rtt
        .globl  _exit
        .globl  _bootdev
        .globl  _cyloffset
#define NOP     inb $0x84,%al ; inb $0x84,%al

#ifdef SMALL
        /* where the disklabel goes if we have one */
        .globl  _disklabel
_disklabel:
        .space 512
        .globl _scsisn
        .set _scsisn, RELOC+0x60
#endif

        .globl  entry
        .set entry,0
        .globl  start

#if     defined(REL) && !defined(SMALL)

        /* relocate program and enter at symbol "start" */

        #movl   $entry-RELOC,%esi       # from beginning of ram
        movl    $0,%esi
        #movl   $entry,%edi             # to relocated area
        movl    $ RELOC,%edi            # to relocated area
        # movl  $_edata-RELOC,%ecx      # this much
        movl    $64*1024,%ecx
        cld
        rep
        movsb
        # relocate program counter to relocation base
        pushl   $start
        ret
#endif

start:

        /* setup stack pointer */

#ifdef REL
        leal    4(%esp),%eax    /* ignore old pc */
        movl    $ RELOC-3*4,%ebx
        /* copy boot parameters */
        pushl   $3*4
        pushl   %ebx
        pushl   %eax
        call    _bcopy
        movl    %ebx,%esp
#else
        /* save old stack state */
        movl    %esp,savearea
        movl    %ebp,savearea+4
        movl    $ RELOC-0x2400,%esp
#endif

        /* clear memory as needed */

        movl    %esp,%esi
#ifdef  REL

        /*
         * Clear Bss and up to 64K heap
         */
        movl    $64*1024,%ebx
        movl    $_end,%eax      # should be movl $_end-_edata but ...
        subl    $_edata,%eax
        #addl   %ebx,%eax
        pushl   %eax
        pushl   $_edata
        call    _bzero

        /*
         * Clear 64K of stack
         */
        movl    %esi,%eax
        subl    %ebx,%eax
        subl    $5*4,%ebx
        pushl   %ebx
        pushl   %eax
        call    _bzero
#else
        movl    $_edata,%edx
        movl    %esp,%eax
        subl    %edx,%eax
        pushl   %edx
        pushl   %esp
        call    _bzero
#endif

        call    _kbdreset       /* resets keyboard and gatea20 brain damage */
        movl    %esi,%esp
        call    _main
        jmp     1f

        .data
_bootdev:       .long   0
_cyloffset:     .long   0
savearea:       .long   0,0     # sp & bp to return to
        .text
        .globl _wait

__rtt:
        pushl   $1000000
        call    _wait
        popl    %eax
        movl    $-7,%eax
        jmp     1f

_exit:
        pushl   $1000000
        call    _wait
        popl    %eax
        movl    4(%esp),%eax
1:
#ifdef  REL
#ifndef SMALL
        call    _reset_cpu
#endif
        movw    $0x1234,%ax
        movw    %ax,0x472       # warm boot
        movl    $0,%esp         # segment violation
        ret
#else
        movl    savearea,%esp
        movl    savearea+4,%ebp
        ret
#endif

        .globl  _inb
_inb:   movl    4(%esp),%edx
        subl    %eax,%eax       # clr eax
        NOP
        inb     %dx,%al
        ret

        .globl  _outb
_outb:  movl    4(%esp),%edx
        NOP
        movl    8(%esp),%eax
        outb    %al,%dx
        ret

        .globl ___udivsi3
___udivsi3:
        movl 4(%esp),%eax
        xorl %edx,%edx
        divl 8(%esp)
        ret

        .globl ___divsi3
___divsi3:
        movl 4(%esp),%eax
        xorl %edx,%edx
        cltd
        idivl 8(%esp)
        ret

        #
        # bzero (base,cnt)
        #

        .globl _bzero
_bzero:
        pushl   %edi
        movl    8(%esp),%edi
        movl    12(%esp),%ecx
        movb    $0x00,%al
        cld
        rep
        stosb
        popl    %edi
        ret

        #
        # bcopy (src,dst,cnt)
        # NOTE: does not (yet) handle overlapped copies
        #

        .globl  _bcopy
_bcopy:
        pushl   %esi
        pushl   %edi
        movl    12(%esp),%esi
        movl    16(%esp),%edi
        movl    20(%esp),%ecx
        cld
        rep
        movsb
        popl    %edi
        popl    %esi
        ret

        # insw(port,addr,cnt)
        .globl  _insw
_insw:
        pushl   %edi
        movw    8(%esp),%dx
        movl    12(%esp),%edi
        movl    16(%esp),%ecx
        NOP
        cld
        nop
        .byte 0x66,0xf2,0x6d    # rep insw
        nop
        movl    %edi,%eax
        popl    %edi
        ret

        # outsw(port,addr,cnt)
        .globl  _outsw
_outsw:
        pushl   %esi
        movw    8(%esp),%dx
        movl    12(%esp),%esi
        movl    16(%esp),%ecx
        NOP
        cld
        nop
        .byte 0x66,0xf2,0x6f    # rep outsw
        nop
        movl    %esi,%eax
        popl    %esi
        ret