.{inl, outl} := @use("rel:memory.hb")

config_read := fn(bus: u8, device: u8, func: u8, offset: u8): u32 {
	lbus := @as(u32, bus)
	ldevice := @as(u32, device)
	lfunc := @as(u32, func)
	loffset := @as(u32, offset)

	address := lbus << 16 | ldevice << 11 | lfunc << 8 | loffset & 0xFC | @as(u32, 0x80000000)

	outl(0xCF8, address)
	return inl(0xCFC)
}

config_write := fn(bus: u8, device: u8, func: u8, offset: u8, value: u32): void {
	lbus := @as(u32, bus)
	ldevice := @as(u32, device)
	lfunc := @as(u32, func)
	loffset := @as(u32, offset)

	address := lbus << 16 | ldevice << 11 | lfunc << 8 | loffset & 0xFC | @as(u32, 0x80000000)

	outl(0xCF8, address)
	outl(0xCFC, value)
}

get_header_type := fn(bus: u8, device: u8, func: u8): u8 {
	return @as(u8, config_read(bus, device, func, 0xC) >> 16 & 0xFF)
}

Ids := struct {vendor: u16, device: u16}

get_ids := fn(bus: u8, device: u8, func: u8): Ids {
	res := config_read(bus, device, func, 0)
	return .(@as(u16, res >> 16 & 0xFFFF), @as(u16, res & 0xFFFF))
}

PciDeviceInfo := struct {header_type: u8, device: u8, bus: u8, device_id: Ids, full_class: u16, rev_id: u8}

check_device := fn(bus: u8, device: u8): PciDeviceInfo {
	ids := get_ids(bus, device, 0)
	if ids.vendor == 0xFFFF {
		return .(0, 0, 0, .(0, 0), 0, 0)
	}
	reg2 := config_read(bus, device, 0, 0x8)
	class := @as(u16, reg2 >> 16 & 0xFFFF)
	header_type := get_header_type(bus, device, 0)

	return .(header_type, device, bus, ids, class, @as(u8, reg2 & 0xFF))
}