1 /* $NetBSD: startprog32.S,v 1.3 2023/04/20 00:42:24 manu 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 movl 8(%ebp), %ebx /* %ebx: entry address */ 95 movl 36(%ebp), %edx /* %edx: loaded start address */ 96 97 /* Prepare a new stack */ 98 movl 20(%ebp), %eax /* stack */ 99 subl $4, %eax 100 movl %eax, %edi 101 102 /* Push some number of args onto the stack */ 103 movl 12(%ebp), %ecx /* argc */ 104 movl %ecx, %eax 105 decl %eax 106 shl $2, %eax 107 addl 16(%ebp), %eax /* ptr to last arg */ 108 movl %eax, %esi 109 110 std /* backwards */ 111 rep 112 movsl /* copy %ds:(%esi) -> %es:(%edi) */ 113 cld 114 mov %edi, %esp /* set new stack pointer */ 115 116 /* Copy kernel */ 117 movl 24(%ebp), %edi /* dest */ 118 movl 28(%ebp), %esi /* src */ 119 movl 32(%ebp), %ecx /* size */ 120 121 /* skip copy if same source and destination */ 122 cmpl %edi,%esi 123 jz .Lcopy_done 124 125 #if defined(NO_OVERLAP) 126 movl %ecx, %eax 127 #else 128 movl %edi, %eax 129 subl %esi, %eax 130 cmpl %ecx, %eax /* overlapping? */ 131 movl %ecx, %eax 132 jb .Lbackwards 133 #endif 134 /* nope, copy forwards. */ 135 shrl $2, %ecx /* copy by words */ 136 rep 137 movsl 138 and $3, %eax /* any bytes left? */ 139 jnz .Ltrailing 140 jmp .Lcopy_done 141 142 .Ltrailing: 143 cmp $2, %eax 144 jb 1f 145 movw (%esi), %ax 146 movw %ax, (%edi) 147 je .Lcopy_done 148 movb 2(%esi), %al 149 movb %al, 2(%edi) 150 jmp .Lcopy_done 151 1: movb (%esi), %al 152 movb %al, (%edi) 153 jmp .Lcopy_done 154 155 #if !defined(NO_OVERLAP) 156 .Lbackwards: 157 addl %ecx, %edi /* copy backwards. */ 158 addl %ecx, %esi 159 and $3, %eax /* any fractional bytes? */ 160 jnz .Lback_align 161 .Lback_aligned: 162 shrl $2, %ecx 163 subl $4, %esi 164 subl $4, %edi 165 std 166 rep 167 movsl 168 cld 169 jmp .Lcopy_done 170 171 .Lback_align: 172 sub %eax, %esi 173 sub %eax, %edi 174 cmp $2, %eax 175 jb 1f 176 je 2f 177 movb 2(%esi), %al 178 movb %al, 2(%edi) 179 2: movw (%esi), %ax 180 movw %ax, (%edi) 181 jmp .Lback_aligned 182 1: movb (%esi), %al 183 movb %al, (%edi) 184 jmp .Lback_aligned 185 #endif 186 /* End of copy kernel */ 187 .Lcopy_done: 188 cld /* LynxOS depends on it */ 189 190 /* Prepare jump address */ 191 lea (start32a - start)(%edx), %eax 192 movl %eax, (start32r - start)(%edx) 193 194 /* Setup GDT */ 195 lea (gdt - start)(%edx), %eax 196 movl %eax, (gdtrr - start)(%edx) 197 lgdt (gdtr - start)(%edx) 198 199 /* Jump to set %cs */ 200 ljmp *(start32r - start)(%edx) 201 202 .align 4 203 start32a: 204 movl $DATA_SEGMENT, %eax 205 movw %ax, %ds 206 movw %ax, %es 207 movw %ax, %fs 208 movw %ax, %gs 209 movw %ax, %ss 210 211 /* Already set new stack pointer */ 212 movl %esp, %ebp 213 214 /* Disable Paging in CR0 */ 215 movl %cr0, %eax 216 andl $(~CR0_PG), %eax 217 movl %eax, %cr0 218 219 /* Disable PAE in CR4 */ 220 movl %cr4, %eax 221 andl $(~CR4_PAE), %eax 222 movl %eax, %cr4 223 224 jmp start32b 225 226 .align 4 227 start32b: 228 xor %eax, %eax 229 movl %ebx, (start32r - start)(%edx) 230 ljmp *(start32r - start)(%edx) 231 232 .align 16 233 start32r: 234 .long 0 235 .long CODE_SEGMENT 236 .align 16 237 gdt: 238 .long 0, 0 239 .byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x9f, 0xcf, 0x00 240 .byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x93, 0xcf, 0x00 241 gdtr: 242 .word gdtr - gdt 243 gdtrr: 244 .quad 245 start32end: 246 /* Space for the stack */ 247 .align 16 248 .space 8192 249 startprog32_end: 250
Indexes created Thu Sep 25 16:09:42 GMT 2025