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+/*
+ * This file is part of the libpayload project.
+ *
+ * Copyright (C) 2008 Advanced Micro Devices, Inc.
+ *
+ * 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.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 AUTHOR 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.
+ */
+
+ .globl _entry, _leave
+ .text
+ .align 4
+
+/*
+ * Our entry point - assume that the CPU is in 32 bit protected mode and
+ * all segments are in a flat model. That's our operating mode, so we won't
+ * change anything.
+ */
+_entry:
+#if 0
+ call _init
+
+ /* We're back - go back to the bootloader. */
+ ret
+ .align 4
+
+
+/*
+ * This function saves off the previous stack and switches us to our
+ * own execution environment.
+ */
+_init:
+ /* No interrupts, please. */
+ cli
+
+ /* Store current stack pointer. */
+ movl %esp, %esi
+
+ /* Store EAX and EBX */
+
+ movl %eax,loader_eax
+ movl %ebx,loader_ebx
+
+ /* Setup new stack. */
+ movl $_stack, %ebx
+
+ movl %ebx, %esp
+
+ /* Save old stack pointer. */
+ pushl %esi
+
+ /* Let's rock. */
+ call start_main
+
+#endif
+ /* %eax has the return value - pass it on unmolested */
+_leave:
+#if 0
+ /* Get old stack pointer. */
+ popl %ebx
+
+ /* Restore old stack. */
+ movl %ebx, %esp
+
+ /* Return to the original context. */
+ ret
+#endif