bsdstart.S revision 1.3
1 1.3 snj /* $NetBSD: bsdstart.S,v 1.3 2009/10/20 19:10:11 snj Exp $ */ 2 1.1 he 3 1.1 he /* 4 1.1 he * Copyright (c) 1995 L. Weppelman 5 1.1 he * All rights reserved. 6 1.1 he * 7 1.1 he * Redistribution and use in source and binary forms, with or without 8 1.1 he * modification, are permitted provided that the following conditions 9 1.1 he * are met: 10 1.1 he * 1. Redistributions of source code must retain the above copyright 11 1.1 he * notice, this list of conditions and the following disclaimer. 12 1.1 he * 2. Redistributions in binary form must reproduce the above copyright 13 1.1 he * notice, this list of conditions and the following disclaimer in the 14 1.1 he * documentation and/or other materials provided with the distribution. 15 1.1 he * 16 1.1 he * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 1.1 he * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 1.1 he * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 1.1 he * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 1.1 he * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 1.1 he * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 1.1 he * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 1.1 he * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 1.1 he * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 1.1 he * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 1.1 he */ 27 1.1 he 28 1.1 he /* 29 1.1 he * This function sets up the registers according to the kernel parameter block, 30 1.1 he * disables the MMU and jumps to the kernel. 31 1.1 he * 32 1.1 he * bsd_startup(struct kparamb *) 33 1.1 he */ 34 1.1 he 35 1.1 he #ifndef TOSTOOLS 36 1.1 he #include <machine/asm.h> 37 1.1 he #endif 38 1.1 he 39 1.1 he #ifdef TOSTOOLS 40 1.1 he .globl _bsd_startup 41 1.1 he _bsd_startup: 42 1.1 he #else 43 1.1 he ENTRY_NOPROFILE(bsd_startup) 44 1.1 he #endif 45 1.1 he movw #0x2700,%sr 46 1.1 he 47 1.1 he | the BSD kernel wants values into the following registers: 48 1.1 he | d0: ttmem-size 49 1.1 he | d1: stmem-size 50 1.1 he | d2: cputype 51 1.1 he | d3: boothowto 52 1.1 he | d4: length of loaded kernel 53 1.1 he | d5: start of fastram 54 1.1 he | a0: start of loaded kernel 55 1.1 he | a1: end of symbols (esym) 56 1.1 he | All other registers zeroed for possible future requirements. 57 1.1 he 58 1.1 he movl %sp@(4),%a3 | a3 points to parameter block 59 1.1 he #ifdef TOSTOOLS 60 1.1 he lea _bsd_startup,%sp | make sure we have a good stack *** 61 1.1 he #endif 62 1.1 he movl %a3@,%a0 | loaded kernel 63 1.1 he movl %a3@(8),%d0 | kernel entry point 64 1.1 he addl %a0,%d0 | added makes our absolute entry point 65 1.1 he movl %d0,%sp@- | push entry point *** 66 1.1 he movl %a3@(12),%d1 | stmem-size 67 1.1 he movl %a3@(16),%d0 | ttmem-size 68 1.1 he movl %a3@(20),%d2 | bootflags 69 1.1 he movl %a3@(24),%d3 | boothowto 70 1.1 he movl %a3@(4),%d4 | length of loaded kernel 71 1.1 he movl %a3@(28),%d5 | start of fastram 72 1.1 he movl %a3@(32),%a1 | end of symbols 73 1.1 he subl %a5,%a5 | target, load to 0 74 1.1 he movl %d2,%d6 75 1.1 he andb #0x50,%d6 | Is this an 68040/68060? 76 1.1 he beqs 0f 77 1.1 he 78 1.1 he | Turn off 68040 type MMU 79 1.1 he .word 0x4e7b,0xd003 | movec a5,tc 80 1.1 he .word 0x4e7b,0xd806 | movec a5,urp 81 1.1 he .word 0x4e7b,0xd807 | movec a5,srp 82 1.1 he .word 0x4e7b,0xd004 | movec a5,itt0 83 1.1 he .word 0x4e7b,0xd005 | movec a5,itt1 84 1.1 he .word 0x4e7b,0xd006 | movec a5,dtt0 85 1.1 he .word 0x4e7b,0xd007 | movec a5,dtt1 86 1.1 he .word 0xf4f8 | cpusha bc - push and inval caches 87 1.1 he bras 1f 88 1.1 he 89 1.1 he 0: lea %pc@(zero),%a3 90 1.1 he pmove %a3@,%tc | Turn off MMU 91 1.1 he pmove %a3@(-4),%crp | crp = nullrp 92 1.1 he pmove %a3@(-4),%srp | srp = nullrp 93 1.1 he btst #3,%d2 | Is this an 68030? 94 1.1 he beqs 1f 95 1.1 he 96 1.1 he | Turn off 68030 TT registers 97 1.1 he .word 0xf013,0x0800 | pmove a3@,tt0 98 1.1 he .word 0xf013,0x0c00 | pmove a3@,tt1 99 1.1 he 100 1.1 he 1: movq #0,%d6 | would have known contents 101 1.1 he movc %d6,%cacr | turn off the caches 102 1.1 he movl %d6,%d7 103 1.1 he movl %d6,%a2 104 1.1 he movl %d6,%a3 105 1.1 he movl %d6,%a4 106 1.1 he movl %d6,%a5 107 1.1 he movl %d6,%a6 108 1.1 he rts | enter kernel at address on stack *** 109 1.1 he 110 1.1 he | A do-nothing MMU root pointer (includes the following long as well) 111 1.1 he | Note that the above code makes assumptions about the order of the following 112 1.1 he | items. 113 1.1 he 114 1.1 he nullrp: .long 0x80000202 115 1.1 he zero: .long 0 116
Indexes created Tue Oct 21 19:09:51 GMT 2025