-- { dg-do run } with System, Ada.Unchecked_Conversion; use System; procedure BLKextract_From_Reg is type Byte is range 0 .. +255; for Byte'size use 8; type RGB is array (1 .. 3) of Byte; for RGB'Size use 24; type RAW_Packet is range 0 .. 2 ** 32 - 1; for RAW_Packet'Size use 32; type Composite_Packet is record Values : RGB; Pad : Byte; end record; for Composite_Packet use record Values at 0 range 0 .. 23; Pad at 3 range 0 .. 7; end record; for Composite_Packet'Size use 32; function To_Composite_Packet is new Ada.Unchecked_Conversion (RAW_Packet, Composite_Packet); function Blob return RGB is RAW_Blob : RAW_Packet := 16#01020304#; begin return To_Composite_Packet (RAW_Blob).Values; end; Blob_Color : RGB := Blob; Expected_Color : RGB; begin if System.Default_Bit_Order = High_Order_First then Expected_Color := (1 => 1, 2 => 2, 3 => 3); else Expected_Color := (1 => 4, 2 => 3, 3 => 2); end if; for I in Blob_Color'Range loop if Blob_Color (I) /= Expected_Color (I) then raise Program_Error; end if; end loop; end;