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use crate::io::*;
// provide functions to parse information provided by grub multiboot
// see docs/multiboot.txt
extern "C" {
static mb_magic: u32;
static mb_info_addr: u32;
}
#[repr(C)]
#[repr(packed)]
#[derive(Debug)]
pub struct MultibootMmap {
pub size: u32,
pub addr: u64,
pub len: u64,
pub mtype: u32,
}
#[repr(C)]
#[repr(packed)]
#[derive(Debug, Clone, Copy)]
pub struct MultibootInfo {
pub flags: MultibootInfoFlags,
pub mem_lower: u32,
pub mem_upper: u32,
}
use bitflags::bitflags;
bitflags! {
/// the MultibootInfoFlags indicate which fields are valid in the MultibootInfo
/// atm we only need the MEM and MMAP flags for memory management info.
#[derive(Copy, Clone, Debug)]
pub struct MultibootInfoFlags: u32 {
const MEM = 1 << 0;
const BOOT_DEVICE = 1 << 1;
const CMDLINE = 1 << 2;
const MODS = 1 << 3;
const SYM_TBL = 1 << 4;
const SHDR = 1 << 5;
const MMAP = 1 << 6;
const DRIVES = 1 << 7;
const CONF_TBL = 1 << 8;
const BL_NAME = 1 << 9;
const APM_TBL = 1 << 10;
const VBE_TBL = 1 << 11;
const FRAMEBUFFER = 1 << 12;
}
}
impl MultibootInfoFlags {
/// only 13 bits of the MB info flags are defined. The other flag bits must
/// be zero for the info block to be valie.
const VALID_MASK: u32 = 0x1FFF;
pub fn check_valid(&self) -> bool {
return self.bits() <= Self::VALID_MASK;
}
}
pub fn check_magic() -> bool {
return unsafe { mb_magic == 0x2BADB002 };
}
pub fn get_mb_info() -> Option<MultibootInfo> {
if !check_magic() {
return None;
}
let mbi = unsafe { *(mb_info_addr as *mut MultibootInfo) };
let flags = mbi.flags;
if !flags.check_valid() {
return None;
}
return Some(mbi);
}
// TODO: expand MultibootInfo struct defs if needed.
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