/* $NetBSD: startprog32.S,v 1.4 2026/05/21 16:59:03 riastradh Exp $ */ /* NetBSD: startprog.S,v 1.4 2016/12/04 08:21:08 maxv Exp */ /* * Ported to boot 386BSD by Julian Elischer (julian@tfs.com) Sept 1992 * * Mach Operating System * Copyright (c) 1992, 1991 Carnegie Mellon University * All Rights Reserved. * * Permission to use, copy, modify and distribute this software and its * documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. * * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie Mellon * the rights to redistribute these changes. */ /* * Copyright 1988, 1989, 1990, 1991, 1992 * by Intel Corporation, Santa Clara, California. * * All Rights Reserved * * Permission to use, copy, modify, and distribute this software and * its documentation for any purpose and without fee is hereby * granted, provided that the above copyright notice appears in all * copies and that both the copyright notice and this permission notice * appear in supporting documentation, and that the name of Intel * not be used in advertising or publicity pertaining to distribution * of the software without specific, written prior permission. * * INTEL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, * IN NO EVENT SHALL INTEL BE LIABLE FOR ANY SPECIAL, INDIRECT, OR * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM * LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT, * NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #include <machine/asm.h> #include <machine/specialreg.h> #define CODE_SEGMENT 0x08 #define DATA_SEGMENT 0x10 .align 16 .globl _C_LABEL(startprog32_size) _C_LABEL(startprog32_size): .long startprog32_end - _C_LABEL(startprog32_start) .text .p2align 4,,15 /* * startprog32(entry,argc,argv,stack,kern_start,kern_load,kern_size,loadaddr) */ ENTRY(startprog32_start) start: pushl %ebp movl %esp, %ebp /* * 8(%ebp): kernel entry address * 12(%ebp): argc * 16(%ebp): argv * 20(%ebp): stack address * 24(%ebp): kernel start address * 28(%ebp): loaded kernel address * 32(%ebp): loaded kernel size * 36(%ebp): loaded start address */ cli movl 8(%ebp), %ebx /* %ebx: entry address */ movl 36(%ebp), %edx /* %edx: loaded start address */ /* Prepare a new stack */ movl 20(%ebp), %eax /* stack */ subl $4, %eax movl %eax, %edi /* Push some number of args onto the stack */ movl 12(%ebp), %ecx /* argc */ movl %ecx, %eax decl %eax shl $2, %eax addl 16(%ebp), %eax /* ptr to last arg */ movl %eax, %esi std /* backwards */ rep movsl /* copy %ds:(%esi) -> %es:(%edi) */ cld mov %edi, %esp /* set new stack pointer */ /* Copy kernel */ movl 24(%ebp), %edi /* dest */ movl 28(%ebp), %esi /* src */ movl 32(%ebp), %ecx /* size */ /* skip copy if same source and destination */ cmpl %edi,%esi jz .Lcopy_done #if defined(NO_OVERLAP) movl %ecx, %eax #else movl %edi, %eax subl %esi, %eax cmpl %ecx, %eax /* overlapping? */ movl %ecx, %eax jb .Lbackwards #endif /* nope, copy forwards. */ shrl $2, %ecx /* copy by words */ rep movsl and $3, %eax /* any bytes left? */ jnz .Ltrailing jmp .Lcopy_done .Ltrailing: cmp $2, %eax jb 1f movw (%esi), %ax movw %ax, (%edi) je .Lcopy_done movb 2(%esi), %al movb %al, 2(%edi) jmp .Lcopy_done 1: movb (%esi), %al movb %al, (%edi) jmp .Lcopy_done #if !defined(NO_OVERLAP) .Lbackwards: addl %ecx, %edi /* copy backwards. */ addl %ecx, %esi and $3, %eax /* any fractional bytes? */ jnz .Lback_align .Lback_aligned: shrl $2, %ecx subl $4, %esi subl $4, %edi std rep movsl cld jmp .Lcopy_done .Lback_align: sub %eax, %esi sub %eax, %edi cmp $2, %eax jb 1f je 2f movb 2(%esi), %al movb %al, 2(%edi) 2: movw (%esi), %ax movw %ax, (%edi) jmp .Lback_aligned 1: movb (%esi), %al movb %al, (%edi) jmp .Lback_aligned #endif /* End of copy kernel */ .Lcopy_done: cld /* LynxOS depends on it */ /* Prepare jump address */ lea (start32a - start)(%edx), %eax movl %eax, (start32r - start)(%edx) /* Setup GDT */ lea (gdt - start)(%edx), %eax movl %eax, (gdtrr - start)(%edx) lgdt (gdtr - start)(%edx) /* Jump to set %cs */ ljmp *(start32r - start)(%edx) .align 4 start32a: movl $DATA_SEGMENT, %eax movw %ax, %ds movw %ax, %es movw %ax, %fs movw %ax, %gs movw %ax, %ss /* Already set new stack pointer */ movl %esp, %ebp /* Disable Paging in CR0 */ movl %cr0, %eax andl $(~CR0_PG), %eax movl %eax, %cr0 /* Disable PAE in CR4 */ movl %cr4, %eax andl $(~CR4_PAE), %eax movl %eax, %cr4 jmp start32b .align 4 start32b: xor %eax, %eax movl %ebx, (start32r - start)(%edx) ljmp *(start32r - start)(%edx) .align 16 start32r: .long 0 .long CODE_SEGMENT .align 16 gdt: .long 0, 0 .byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x9f, 0xcf, 0x00 .byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x93, 0xcf, 0x00 gdtr: .word gdtr - gdt gdtrr: .quad start32end: /* Space for the stack */ .align 16 .space 8192 startprog32_end:
