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const Com = @import("com.zig").Com;
// -- ENTRY POINT ---------------------------------------------------------------
export fn _entry() linksection(".boot") callconv(.naked) noreturn {
asm volatile (
// Disable interrupts.
\\cli
// Clear segment selectors.
\\xor %%ax, %%ax
\\mov %%ax, %%ds
\\mov %%ax, %%es
\\mov %%ax, %%ss
\\mov %%ax, %%fs
\\mov %%ax, %%gs
\\mov $0x7c00, %sp
// Long jump to set cs to 0x0000, as some BIOSes load the MBR
// to either 07c0:0000 or 0000:7c000.
\\ljmp $0x0, $main
);
}
// -- MAIN ----------------------------------------------------------------------
// Global access to COM0.
var com0: ?Com = null;
// main should be "callconv(.naked)", once issue is fixed.
// https://github.com/ziglang/zig/issues/18183
export fn main() noreturn {
com0 = com0 orelse Com.init(Com.COM1);
com0.?.puts("\n\nBooted into mbr.zig\n");
@panic("end reached, crashing kernel");
}
pub const panic = @import("std").debug.FullPanic(panicHandler);
fn panicHandler(msg: []const u8, first_trace_addr: ?usize) noreturn {
_ = first_trace_addr;
com0 = com0 orelse Com.init(Com.COM1);
com0.?.puts("\nPANIC: ");
com0.?.puts(msg);
com0.?.puts("\n");
while (true) {
asm volatile ("hlt");
}
}
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