copy of the original trampoline code, needs to be modified as UNDI needes the used address range

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@19125 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/boot/platform/pxe_ia32/smp_trampoline.S

@@ -0,0 +1,69 @@
+/* 
+** Copyright 2001, Travis Geiselbrecht. All rights reserved.
+** Distributed under the terms of the NewOS License.
+*/
+// expects a stack page like this:
+// (stack has to be at (0x9e000)
+//	0x9effc            : final esp
+//  0x9eff8            : page dir
+//
+//  0x9e000 - 0x9e006  : gdt descriptor
+//	0x9e008 - 0x9e020  : gdt
+//
+// smp_trampoline must be located at 0x9f000
+.globl smp_trampoline
+.globl smp_trampoline_end
+.globl foo
+
+.code16
+smp_trampoline:
+	cli
+	
+	mov    $0x9e00,%ax
+	mov    %ax,%ds
+
+//	lgdt   0x9e000          # load the gdt
+.byte 0x66, 0x0f, 0x01, 0x15, 0x00, 0xe0, 0x09, 0x00
+
+	movl   %cr0,%eax
+	orl    $0x01,%eax
+	movl   %eax,%cr0              # switch into protected mode
+
+.code32
+_trampoline_32:
+	.byte 0x66
+	ljmp   $0x08,$(trampoline_32 - smp_trampoline + 0x9f000)
+trampoline_32:
+	mov    $0x10, %ax
+	mov    %ax, %ds
+	mov    %ax, %es
+	mov    %ax, %fs
+	mov    %ax, %gs
+	mov    %ax, %ss
+
+	movl   $0x9eff8,%esp    # set up the stack pointer
+
+	popl   %eax             # get the page dir
+	movl   %eax,%cr3        # set the page dir
+	
+	popl   %eax             # get the final stack location
+	movl   %eax,%esp
+
+	// load an address for an indirect jump
+	movl   $trampoline_after_paging,%ecx
+
+	movl   %cr0,%eax
+	orl    $0x80000000,%eax
+	movl   %eax,%cr0          # enable paging
+
+	// jump to the address previously loaded. NOTE:
+	// this address is the address at which the code is originally linked,
+	// which is > 1MB. We will be out of the low memory at this point.
+	jmp    *%ecx
+trampoline_after_paging:
+	// just return, the bsp would have set the return address to the
+	// target function at the top of the passed stack
+	ret
+
+smp_trampoline_end:
+