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., 675 Mass Ave, Cambridge, MA 02139, USA.
00017  */
00018 
00019 FILE_LICENCE ( GPL2_OR_LATER );
00020 
00021 #include <stdint.h>
00022 #include <realmode.h>
00023 #include <bios.h>
00024 #include <basemem.h>
00025 #include <gpxe/hidemem.h>
00026 
00027 /** @file
00028  *
00029  * Base memory allocation
00030  *
00031  */
00032 
00033 /**
00034  * Set the BIOS free base memory counter
00035  *
00036  * @v new_fbms          New free base memory counter (in kB)
00037  */
00038 void set_fbms ( unsigned int new_fbms ) {
00039         uint16_t fbms = new_fbms;
00040 
00041         /* Update the BIOS memory counter */
00042         put_real ( fbms, BDA_SEG, BDA_FBMS );
00043 
00044         /* Update our hidden memory region map */
00045         hide_basemem();
00046 }