Key codes and key labels

Bits 0–8 — Unique code assigned to the key

Bit 9 — The SHIFT key modifier (512)

Bit 10 — The ALT or ESC key modifier (1024)

Bit 11 — The CTRL key modifier (2048)

Bits 12–15 — Reserved bits

If you press CTRL plus an alphabetic character or the (@, \, ], ^, or _ special characters), the AVM turns the CTRL key modifier off and maps to the appropriate character code. For example, CTRL+A is mapped to keycode 1, which accords with the ASCII standard (and therefore most 7–bit character code pages).

If you press SHIFT plus a code page character, the AVM turns off the SHIFT key modifier and maps to the appropriate character code. For example, SHIFT+A is equivalent to A, and A is mapped to keycode 65, which accords with the ASCII standard (and therefore most 7–bit character code pages). Also, many code page characters (for example, the comma) do not have uppercase equivalents; therefore, the SHIFT key modifier is turned off.

If you press ALT plus an alphabetic character, the AVM maps to the uppercase alphabetic characters. For example, ALT+A and ALT+a are both mapped to keycode 1089. The keycode 1089 corresponds to the keycode 65 (A) with the ALT key modifier turned on (65 + 1024 = 1089).