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authorSebastian Schmelzer2010-10-25 16:53:54 +0200
committerSebastian Schmelzer2010-10-25 16:53:54 +0200
commit3050a9253437f4a4b5ad4bf3b3efdc3c660a5137 (patch)
tree91ac22153e416aac7ca20916b314b5e2ffa871b1 /contrib/syslinux-4.02/memdisk/start32.S
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initial import of sc2010 scripts ..HEADmaster
Diffstat (limited to 'contrib/syslinux-4.02/memdisk/start32.S')
-rw-r--r--contrib/syslinux-4.02/memdisk/start32.S101
1 files changed, 101 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/memdisk/start32.S b/contrib/syslinux-4.02/memdisk/start32.S
new file mode 100644
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+++ b/contrib/syslinux-4.02/memdisk/start32.S
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+/* -----------------------------------------------------------------------
+ *
+ * Copyright 2003-2009 H. Peter Anvin - All Rights Reserved
+ * Copyright 2009 Intel Corporation; author: H. Peter Anvin
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston MA 02110-1301, USA; either version 2 of the License, or
+ * (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * Simple stub to get us to the right point in the 32-bit code;
+ * this module must be linked first
+ */
+
+ .section ".init", "ax"
+ .globl _start
+_start:
+ /* Zero the bss */
+ cld
+ movl $__bss_start, %edi
+ movl $__bss_end, %ecx
+ subl %edi, %ecx
+ xorl %eax, %eax
+ shrl $2, %ecx
+ rep ; stosl
+
+ /* Set up the protected-mode IDT and the interrupt jump buffers */
+ movl $idt, %edi
+ movl $ijb, %eax
+ movl $0xee000000, %ebx /* Interrupt gate */
+ movw %cs, %bx /* Target segment */
+
+ /* Make the IDT */
+ movl $256, %ecx
+1:
+ stosl
+ stosl
+ movl %ebx, -6(%edi)
+ addl $8, %eax
+ loop 1b
+
+ /*
+ * Each entry in the interrupt jump buffer contains the following
+ * instructions:
+ *
+ * 60 pushal
+ * b0xx movb $xx, %al # interrupt number
+ * e9xxxxxxxx jmp handle_interrupt
+ */
+ movl $0xe900b060, %eax
+ movl $256, %ecx
+1:
+ movl %eax, (%edi)
+ addl $(1 << 16), %eax
+ movl $handle_interrupt-8, %edx
+ subl %edi, %edx
+ movl %edx, 4(%edi)
+ addl $8, %edi
+ loop 1b
+
+ lidtl idt_ptr
+
+ /* Save arguments, switch stacks */
+ movl %esp, %eax /* Pointer to arguments */
+ movl $__stack_end, %esp
+
+ call setup
+ jmp *(rm_args) /* First argument is return */
+
+ .section ".text","ax"
+ .globl intcall
+ .type intcall, @function
+intcall:
+ jmp *(rm_args+1*4) /* Intcall is argument 1 */
+ .size intcall, .-intcall
+
+ .type handle_interrupt, @function
+handle_interrupt:
+ jmp *(rm_args+4*4) /* Interrupt pointer is argument 4 */
+ .size handle_interrupt, .-handle_interrupt
+
+ .section ".rodata","a"
+idt_ptr:
+ .word 8*256-1
+ .long idt
+ .word 0
+
+ .section ".bss.large","aw"
+ .balign 2048
+idt:
+ .space 8*256
+ijb:
+ .space 8*256
+
+__stack:
+ .space 65536
+__stack_end: