startprog32.S revision 1.1
1 /* $NetBSD: startprog32.S,v 1.1 2017/02/21 10:53:37 nonaka Exp $ */ 2 /* NetBSD: startprog.S,v 1.4 2016/12/04 08:21:08 maxv Exp */ 3 4 /* 5 * Ported to boot 386BSD by Julian Elischer (julian (at) tfs.com) Sept 1992 6 * 7 * Mach Operating System 8 * Copyright (c) 1992, 1991 Carnegie Mellon University 9 * All Rights Reserved. 10 * 11 * Permission to use, copy, modify and distribute this software and its 12 * documentation is hereby granted, provided that both the copyright 13 * notice and this permission notice appear in all copies of the 14 * software, derivative works or modified versions, and any portions 15 * thereof, and that both notices appear in supporting documentation. 16 * 17 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 18 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR 19 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 20 * 21 * Carnegie Mellon requests users of this software to return to 22 * 23 * Software Distribution Coordinator or Software.Distribution (at) CS.CMU.EDU 24 * School of Computer Science 25 * Carnegie Mellon University 26 * Pittsburgh PA 15213-3890 27 * 28 * any improvements or extensions that they make and grant Carnegie Mellon 29 * the rights to redistribute these changes. 30 */ 31 32 /* 33 * Copyright 1988, 1989, 1990, 1991, 1992 34 * by Intel Corporation, Santa Clara, California. 35 * 36 * All Rights Reserved 37 * 38 * Permission to use, copy, modify, and distribute this software and 39 * its documentation for any purpose and without fee is hereby 40 * granted, provided that the above copyright notice appears in all 41 * copies and that both the copyright notice and this permission notice 42 * appear in supporting documentation, and that the name of Intel 43 * not be used in advertising or publicity pertaining to distribution 44 * of the software without specific, written prior permission. 45 * 46 * INTEL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE 47 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, 48 * IN NO EVENT SHALL INTEL BE LIABLE FOR ANY SPECIAL, INDIRECT, OR 49 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 50 * LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT, 51 * NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION 52 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 53 */ 54 55 #include <machine/asm.h> 56 #include <machine/specialreg.h> 57 58 #define CODE_SEGMENT 0x08 59 #define DATA_SEGMENT 0x10 60 61 .align 16 62 .globl _C_LABEL(startprog32) 63 _C_LABEL(startprog32): 64 .quad 0 65 66 .globl _C_LABEL(startprog32_size) 67 _C_LABEL(startprog32_size): 68 .long startprog32_end - _C_LABEL(startprog32_start) 69 70 .text 71 .p2align 4,,15 72 73 /* 74 * startprog32(entry,argc,argv,stack,kern_start,kern_load,kern_size,loadaddr) 75 */ 76 ENTRY(startprog32_start) 77 start: 78 pushl %ebp 79 movl %esp, %ebp 80 81 /* 82 * 8(%ebp): kernel entry address 83 * 12(%ebp): argc 84 * 16(%ebp): argv 85 * 20(%ebp): stack address 86 * 24(%ebp): kernel start address 87 * 28(%ebp): loaded kernel address 88 * 32(%ebp): loaded kernel size 89 * 36(%ebp): loaded start address 90 */ 91 92 cli 93 94 /* Prepare a new stack */ 95 movl 20(%ebp), %eax /* stack */ 96 subl $4, %eax 97 movl %eax, %edi 98 99 /* Push some number of args onto the stack */ 100 movl 12(%ebp), %ecx /* argc */ 101 movl %ecx, %eax 102 decl %eax 103 shl $2, %eax 104 addl 16(%ebp), %eax /* ptr to last arg */ 105 movl %eax, %esi 106 107 std /* backwards */ 108 rep 109 movsl /* copy %ds:(%esi) -> %es:(%edi) */ 110 cld 111 mov %edi, %edx /* %edx: new stack pointer */ 112 113 /* Copy kernel */ 114 movl 24(%esp), %edi /* dest */ 115 movl 28(%esp), %esi /* src */ 116 movl 32(%esp), %ecx /* size */ 117 #if defined(NO_OVERLAP) 118 movl %ecx, %eax 119 #else 120 movl %edi, %eax 121 subl %esi, %eax 122 cmpl %ecx, %eax /* overlapping? */ 123 movl %ecx, %eax 124 jb .Lbackwards 125 #endif 126 /* nope, copy forwards. */ 127 shrl $2, %ecx /* copy by words */ 128 rep 129 movsl 130 and $3, %eax /* any bytes left? */ 131 jnz .Ltrailing 132 jmp .Lcopy_done 133 134 .Ltrailing: 135 cmp $2, %eax 136 jb 1f 137 movw (%esi), %ax 138 movw %ax, (%edi) 139 je .Lcopy_done 140 movb 2(%esi), %al 141 movb %al, 2(%edi) 142 jmp .Lcopy_done 143 1: movb (%esi), %al 144 movb %al, (%edi) 145 jmp .Lcopy_done 146 147 #if !defined(NO_OVERLAP) 148 .Lbackwards: 149 addl %ecx, %edi /* copy backwards. */ 150 addl %ecx, %esi 151 and $3, %eax /* any fractional bytes? */ 152 jnz .Lback_align 153 .Lback_aligned: 154 shrl $2, %ecx 155 subl $4, %esi 156 subl $4, %edi 157 std 158 rep 159 movsl 160 cld 161 jmp .Lcopy_done 162 163 .Lback_align: 164 sub %eax, %esi 165 sub %eax, %edi 166 cmp $2, %eax 167 jb 1f 168 je 2f 169 movb 2(%esi), %al 170 movb %al, 2(%edi) 171 2: movw (%esi), %ax 172 movw %ax, (%edi) 173 jmp .Lback_aligned 174 1: movb (%esi), %al 175 movb %al, (%edi) 176 jmp .Lback_aligned 177 #endif 178 /* End of copy kernel */ 179 .Lcopy_done: 180 cld /* LynxOS depends on it */ 181 182 movl 8(%ebp), %esi /* %esi: entry address */ 183 movl 36(%ebp), %edi /* %edi: loaded start address */ 184 185 /* Prepare jump address */ 186 lea (start32a - start)(%edi), %eax 187 movl %eax, (start32r - start)(%edi) 188 189 /* Setup GDT */ 190 lea (gdt - start)(%edi), %eax 191 movl %eax, (gdtrr - start)(%edi) 192 lgdt (gdtr - start)(%edi) 193 194 /* Jump to set %cs */ 195 ljmp *(start32r - start)(%edi) 196 197 .align 4 198 start32a: 199 movl $DATA_SEGMENT, %eax 200 movw %ax, %ds 201 movw %ax, %es 202 movw %ax, %fs 203 movw %ax, %gs 204 movw %ax, %ss 205 206 movl %edx, %esp 207 208 /* Disable Paging in CR0 */ 209 movl %cr0, %eax 210 andl $(~CR0_PG), %eax 211 movl %eax, %cr0 212 213 /* Disable PAE in CR4 */ 214 movl %cr4, %eax 215 andl $(~CR4_PAE), %eax 216 movl %eax, %cr4 217 218 jmp start32b 219 220 .align 4 221 start32b: 222 xor %eax, %eax 223 movl %esi, (start32r - start)(%edi) 224 ljmp *(start32r - start)(%edi) 225 226 .align 16 227 start32r: 228 .long 0 229 .long CODE_SEGMENT 230 .align 16 231 gdt: 232 .long 0, 0 233 .byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x9f, 0xcf, 0x00 234 .byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x93, 0xcf, 0x00 235 gdtr: 236 .word gdtr - gdt 237 gdtrr: 238 .quad 239 start32end: 240 /* Space for the stack */ 241 .align 16 242 .space 8192 243 startprog32_end: 244
Indexes created Tue Sep 30 17:09:57 GMT 2025