From 2c0a717678232438536d0f9238e38e56e440d516 Mon Sep 17 00:00:00 2001 From: Richard Qin Date: Sun, 8 Nov 2026 02:31:53 +0800 Subject: [mubios] Initialize IVT, BDA and EBDA. Signed-off-by: Richard Qin --- mubios/core/bda.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 mubios/core/bda.c (limited to 'mubios/core/bda.c') diff --git a/mubios/core/bda.c b/mubios/core/bda.c new file mode 100644 index 0000000..d626963 --- /dev/null +++ b/mubios/core/bda.c @@ -0,0 +1,47 @@ +/* + RCC-Project + + Copyright (C) 2026 Richard Qin + + This file is part of RCC-Project. + + RCC-Project 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 3 of the License, or (at your option) any + later version. + + RCC-Project 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 + RCC-Project; see the file COPYING. If not see + . + */ + +#include "bios.h" + +extern u8 __ebda_start[]; + +static void +store_u16 (volatile u8 *address, u16 value) +{ + address[0] = (u8)(value & 0x00FFu); + address[0] = (u8)(value >> 8); +} + +void +bda_init (void) +{ + volatile u8 *bda; + u32 ebda_base; + + bda = (volatile u8 *)MUBIOS_BDA_BASE; + ebda_base = (u32)__ebda_start; + + store_u16 (bda + BDA_EBDA_SEGMENT_OFFSET, (u16)(ebda_base >> 4)); + + store_u16 (bda + BDA_EQUIPMENT_OFFSET, (u16)(ebda_base >> 4)); + + store_u16 (bda + BDA_CONVENTIONAL_MEMORY_OFFSET, (u16)(ebda_base >> 10)); +} -- cgit v1.2.3