1 /* $NetBSD: bsdstart.S,v 1.3 2009/10/20 19:10:11 snj Exp $ */ 2 3 /* 4 * Copyright (c) 1995 L. Weppelman 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 /* 29 * This function sets up the registers according to the kernel parameter block, 30 * disables the MMU and jumps to the kernel. 31 * 32 * bsd_startup(struct kparamb *) 33 */ 34 35 #ifndef TOSTOOLS 36 #include <machine/asm.h> 37 #endif 38 39 #ifdef TOSTOOLS 40 .globl _bsd_startup 41 _bsd_startup: 42 #else 43 ENTRY_NOPROFILE(bsd_startup) 44 #endif 45 movw #0x2700,%sr 46 47 | the BSD kernel wants values into the following registers: 48 | d0: ttmem-size 49 | d1: stmem-size 50 | d2: cputype 51 | d3: boothowto 52 | d4: length of loaded kernel 53 | d5: start of fastram 54 | a0: start of loaded kernel 55 | a1: end of symbols (esym) 56 | All other registers zeroed for possible future requirements. 57 58 movl %sp@(4),%a3 | a3 points to parameter block 59 #ifdef TOSTOOLS 60 lea _bsd_startup,%sp | make sure we have a good stack *** 61 #endif 62 movl %a3@,%a0 | loaded kernel 63 movl %a3@(8),%d0 | kernel entry point 64 addl %a0,%d0 | added makes our absolute entry point 65 movl %d0,%sp@- | push entry point *** 66 movl %a3@(12),%d1 | stmem-size 67 movl %a3@(16),%d0 | ttmem-size 68 movl %a3@(20),%d2 | bootflags 69 movl %a3@(24),%d3 | boothowto 70 movl %a3@(4),%d4 | length of loaded kernel 71 movl %a3@(28),%d5 | start of fastram 72 movl %a3@(32),%a1 | end of symbols 73 subl %a5,%a5 | target, load to 0 74 movl %d2,%d6 75 andb #0x50,%d6 | Is this an 68040/68060? 76 beqs 0f 77 78 | Turn off 68040 type MMU 79 .word 0x4e7b,0xd003 | movec a5,tc 80 .word 0x4e7b,0xd806 | movec a5,urp 81 .word 0x4e7b,0xd807 | movec a5,srp 82 .word 0x4e7b,0xd004 | movec a5,itt0 83 .word 0x4e7b,0xd005 | movec a5,itt1 84 .word 0x4e7b,0xd006 | movec a5,dtt0 85 .word 0x4e7b,0xd007 | movec a5,dtt1 86 .word 0xf4f8 | cpusha bc - push and inval caches 87 bras 1f 88 89 0: lea %pc@(zero),%a3 90 pmove %a3@,%tc | Turn off MMU 91 pmove %a3@(-4),%crp | crp = nullrp 92 pmove %a3@(-4),%srp | srp = nullrp 93 btst #3,%d2 | Is this an 68030? 94 beqs 1f 95 96 | Turn off 68030 TT registers 97 .word 0xf013,0x0800 | pmove a3@,tt0 98 .word 0xf013,0x0c00 | pmove a3@,tt1 99 100 1: movq #0,%d6 | would have known contents 101 movc %d6,%cacr | turn off the caches 102 movl %d6,%d7 103 movl %d6,%a2 104 movl %d6,%a3 105 movl %d6,%a4 106 movl %d6,%a5 107 movl %d6,%a6 108 rts | enter kernel at address on stack *** 109 110 | A do-nothing MMU root pointer (includes the following long as well) 111 | Note that the above code makes assumptions about the order of the following 112 | items. 113 114 nullrp: .long 0x80000202 115 zero: .long 0 116
Indexes created Sun Oct 19 19:09:49 GMT 2025