/* $OpenBSD: srt0.S,v 1.3 2012/10/12 15:00:32 jsing Exp $ */ /* * Copyright (c) 1997 Michael Shalayeff * 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 REGENTS OR CONTRIBUTORS 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. * */ #include #include #define BOOTSTACK 0xfffc .globl _C_LABEL(end) .globl _C_LABEL(edata) .globl _C_LABEL(boot) .globl _C_LABEL(_rtt) .globl _C_LABEL(bios_bootdev) .globl _ASM_LABEL(pmm_init) .globl Gdtr .text .align 16 .code16 .globl _start _start: popl %eax cmpl $BOOTMAGIC, %eax je 1f #ifdef DEBUG movl $0xb80a0, %ebx addr32 movl $0x07420742, (%ebx) #endif 1: popl %edx cli pushl %cs popl %ds addr32 data32 lgdt (Gdtr - LINKADDR) movl %cr0, %eax orl $CR0_PE, %eax data32 movl %eax, %cr0 data32 ljmp $8, $1f 1: .code32 movl $0x10,%eax mov %ax,%ds mov %ax,%ss mov %ax,%es mov %ax,%fs mov %ax,%gs movl $BOOTSTACK,%esp pushl %edx movl %edx, _C_LABEL(bios_bootdev) /* Now do it all */ #ifdef DEBUG movl $0xb80a4, %ebx movl $0x07520752, (%ebx) #endif /* zero .bss */ xorl %eax, %eax movl $_C_LABEL(end), %ecx subl $_C_LABEL(edata),%ecx movl $_C_LABEL(edata), %edi cld rep; stosb call _ASM_LABEL(pmm_init) call _C_LABEL(boot) jmp _C_LABEL(_rtt)