[bios] Add bin-x86_64-pcbios build platform

Move most arch/i386 files to arch/x86, and adjust the contents of the
Makefiles and the include/bits/*.h headers to reflect the new
locations.

This patch makes no substantive code changes, as can be seen using a
rename-aware diff (e.g. "git show -M5").

This patch does not make the pcbios platform functional for x86_64; it
merely allows it to compile without errors.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/arch/x86/interface/pcbios/bios_reboot.c

@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2010 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * 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; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/** @file
+ *
+ * Standard PC-BIOS reboot mechanism
+ *
+ */
+
+#include <ipxe/reboot.h>
+#include <realmode.h>
+#include <bios.h>
+
+/**
+ * Reboot system
+ *
+ * @v warm		Perform a warm reboot
+ */
+static void bios_reboot ( int warm ) {
+	uint16_t flag;
+
+	/* Configure BIOS for cold/warm reboot */
+	flag = ( warm ? BDA_REBOOT_WARM : 0 );
+	put_real ( flag, BDA_SEG, BDA_REBOOT );
+
+	/* Jump to system reset vector */
+	__asm__ __volatile__ ( REAL_CODE ( "ljmp $0xf000, $0xfff0" ) : : );
+}
+
+PROVIDE_REBOOT ( pcbios, reboot, bios_reboot );