/* $NetBSD: bsdstart.S,v 1.3 2009/10/20 19:10:11 snj Exp $ */
/*
* Copyright (c) 1995 L. Weppelman
* All rights reserved.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
/*
* This function sets up the registers according to the kernel parameter block,
* disables the MMU and jumps to the kernel.
*
* bsd_startup(struct kparamb *)
*/
#ifndef TOSTOOLS
#include <machine/asm.h>
#endif
#ifdef TOSTOOLS
.globl _bsd_startup
_bsd_startup:
#else
ENTRY_NOPROFILE(bsd_startup)
#endif
movw #0x2700,%sr
| the BSD kernel wants values into the following registers:
| d0: ttmem-size
| d1: stmem-size
| d2: cputype
| d3: boothowto
| d4: length of loaded kernel
| d5: start of fastram
| a0: start of loaded kernel
| a1: end of symbols (esym)
| All other registers zeroed for possible future requirements.
movl %sp@(4),%a3 | a3 points to parameter block
#ifdef TOSTOOLS
lea _bsd_startup,%sp | make sure we have a good stack ***
#endif
movl %a3@,%a0 | loaded kernel
movl %a3@(8),%d0 | kernel entry point
addl %a0,%d0 | added makes our absolute entry point
movl %d0,%sp@- | push entry point ***
movl %a3@(12),%d1 | stmem-size
movl %a3@(16),%d0 | ttmem-size
movl %a3@(20),%d2 | bootflags
movl %a3@(24),%d3 | boothowto
movl %a3@(4),%d4 | length of loaded kernel
movl %a3@(28),%d5 | start of fastram
movl %a3@(32),%a1 | end of symbols
subl %a5,%a5 | target, load to 0
movl %d2,%d6
andb #0x50,%d6 | Is this an 68040/68060?
beqs 0f
| Turn off 68040 type MMU
.word 0x4e7b,0xd003 | movec a5,tc
.word 0x4e7b,0xd806 | movec a5,urp
.word 0x4e7b,0xd807 | movec a5,srp
.word 0x4e7b,0xd004 | movec a5,itt0
.word 0x4e7b,0xd005 | movec a5,itt1
.word 0x4e7b,0xd006 | movec a5,dtt0
.word 0x4e7b,0xd007 | movec a5,dtt1
.word 0xf4f8 | cpusha bc - push and inval caches
bras 1f
0: lea %pc@(zero),%a3
pmove %a3@,%tc | Turn off MMU
pmove %a3@(-4),%crp | crp = nullrp
pmove %a3@(-4),%srp | srp = nullrp
btst #3,%d2 | Is this an 68030?
beqs 1f
| Turn off 68030 TT registers
.word 0xf013,0x0800 | pmove a3@,tt0
.word 0xf013,0x0c00 | pmove a3@,tt1
1: movq #0,%d6 | would have known contents
movc %d6,%cacr | turn off the caches
movl %d6,%d7
movl %d6,%a2
movl %d6,%a3
movl %d6,%a4
movl %d6,%a5
movl %d6,%a6
rts | enter kernel at address on stack ***
| A do-nothing MMU root pointer (includes the following long as well)
| Note that the above code makes assumptions about the order of the following
| items.
nullrp: .long 0x80000202
zero: .long 0