diff options
Diffstat (limited to 'qemu/roms/ipxe/src/drivers/bitbash/bitbash.c')
-rw-r--r-- | qemu/roms/ipxe/src/drivers/bitbash/bitbash.c | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/qemu/roms/ipxe/src/drivers/bitbash/bitbash.c b/qemu/roms/ipxe/src/drivers/bitbash/bitbash.c new file mode 100644 index 000000000..23ca30356 --- /dev/null +++ b/qemu/roms/ipxe/src/drivers/bitbash/bitbash.c @@ -0,0 +1,58 @@ +/* + * Copyright (C) 2006 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. + */ + +FILE_LICENCE ( GPL2_OR_LATER ); + +#include <ipxe/bitbash.h> + +/** @file + * + * Bit-bashing interfaces + * + */ + +/** + * Set/clear output bit + * + * @v basher Bit-bashing interface + * @v bit_id Bit number + * @v data Value to write + * + * If @c data is 0, a logic 0 will be written. If @c data is + * non-zero, a logic 1 will be written. + */ +void write_bit ( struct bit_basher *basher, unsigned int bit_id, + unsigned long data ) { + basher->op->write ( basher, bit_id, ( data ? -1UL : 0 ) ); +} + +/** + * Read input bit + * + * @v basher Bit-bashing interface + * @v bit_id Bit number + * @ret data Value read + * + * @c data will always be either 0 or -1UL. The idea is that the + * caller can simply binary-AND the returned value with whatever mask + * it needs to apply. + */ +int read_bit ( struct bit_basher *basher, unsigned int bit_id ) { + return ( basher->op->read ( basher, bit_id ) ? -1UL : 0 ); +} |