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//! Multiboot memory map parser
const boot_limits = @import("../../common/limits/boot.zig");
const serial = @import("../../drivers/serial/serial.zig");
const types = @import("types.zig");
var entries: [boot_limits.MAX_MEMORY_ENTRIES]types.MemoryEntry = undefined;
pub fn parse(addr: u64) []types.MemoryEntry {
const total_size = @as(*u32, @ptrFromInt(addr)).*;
var offset: u64 = 8;
var count: usize = 0;
while (offset < total_size) {
const tag_addr = addr + offset;
const tag_type = @as(*u32, @ptrFromInt(tag_addr)).*;
const tag_size = @as(*u32, @ptrFromInt(tag_addr + 4)).*;
if (tag_type == 0) break;
if (tag_type == 6) {
const entry_size = @as(*u32, @ptrFromInt(tag_addr + 8)).*;
const entry_count = (tag_size - 16) / entry_size;
for (0..entry_count) |i| {
if (count >= boot_limits.MAX_MEMORY_ENTRIES) break;
const entry_addr = tag_addr + 16 + (i * entry_size);
const base = @as(*u64, @ptrFromInt(entry_addr)).*;
const length = @as(*u64, @ptrFromInt(entry_addr + 8)).*;
const entry_type = @as(*u32, @ptrFromInt(entry_addr + 16)).*;
entries[count] = types.MemoryEntry{
.base = base,
.length = length,
.entry_type = entry_type,
};
count += 1;
const status = if (entry_type == 1) "Available" else "Reserved";
serial.printf(" {x}-{x} ({} MB) [{s}]\n", .{
base, base + length - 1, length / (1024 * 1024), status,
});
}
}
offset += (tag_size + 7) & ~@as(u64, 7);
}
return entries[0..count];
}
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