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
index 0000000..4fb0537
--- /dev/null
+++ b/contrib/syslinux-4.02/memdisk/start32.S
@@ -0,0 +1,101 @@
+/* -----------------------------------------------------------------------
+ *
+ *   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: