iPXE
basemem.c
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00001 /*
00002  * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
00003  *
00004  * This program is free software; you can redistribute it and/or
00005  * modify it under the terms of the GNU General Public License as
00006  * published by the Free Software Foundation; either version 2 of the
00007  * License, or any later version.
00008  *
00009  * This program is distributed in the hope that it will be useful, but
00010  * WITHOUT ANY WARRANTY; without even the implied warranty of
00011  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012  * General Public License for more details.
00013  *
00014  * You should have received a copy of the GNU General Public License
00015  * along with this program; if not, write to the Free Software
00016  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
00017  * 02110-1301, USA.
00018  *
00019  * You can also choose to distribute this program under the terms of
00020  * the Unmodified Binary Distribution Licence (as given in the file
00021  * COPYING.UBDL), provided that you have satisfied its requirements.
00022  */
00023 
00024 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
00025 
00026 #include <stdint.h>
00027 #include <realmode.h>
00028 #include <bios.h>
00029 #include <basemem.h>
00030 #include <ipxe/hidemem.h>
00031 
00032 /** @file
00033  *
00034  * Base memory allocation
00035  *
00036  */
00037 
00038 /**
00039  * Set the BIOS free base memory counter
00040  *
00041  * @v new_fbms          New free base memory counter (in kB)
00042  */
00043 void set_fbms ( unsigned int new_fbms ) {
00044         uint16_t fbms = new_fbms;
00045 
00046         /* Update the BIOS memory counter */
00047         put_real ( fbms, BDA_SEG, BDA_FBMS );
00048 
00049         /* Update our hidden memory region map */
00050         hide_basemem();
00051 }