Int 5B

TI Professional PC - KEYBOARD MAPPING HOOK

CF set
AH = shift state (see #03247)
AL = scan code (see #03214)

Return:
BX, CX, DI, ES may be destroyed
various return methods are supported:
IRET, AX unchanged:
Process keystroke normally
IRET, AL = FFh:
Discard keystroke
IRET, AX changed:
Process modified keystroke
chain to old INT 5B:
Allow other handlers to look at (possibly
modified) keystroke in AX
RETF 2, CF clear:
Place returned AX into keyboard buffer without
any further processing

Notes: Invoked by the keyboard ISR, and used to remap the keyboard. If CF is clear on entry, some other handler has processed the keystroke and the current handler should not modify it, instead performing a RETF 2 or IRET (after clearing CF on the stack). When requesting that a value be placed directly into the keyboard buffer, AL and AH may not *both* be nonzero (the TI does not return scan codes as part of the key code for non-extended keys)

Bitfields for TI Professional PC keyboard mapping hook shift states: Bit(s) Description (Table 03247) 7 CAPS LOCK is on 6-4 reserved (0) 3 repeated key 2 Shift is pressed 1 Alt is pressed 0 Ctrl is pressed

Category: Vendor-specific BIOS Extensions - Int 5Bh - T

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