IBM PC CONVERTIBLE

Keyboard Data NMI (KBNMI_DATA)
007D
0000
004B
0038
0008
0080
0057
025F
025F
IE
0260 07
0261
; *******************************************************************
; LOCAL EQUATES FOR KEYBOARD NMI PROCESSING
; *******************************************************************
KBNMLDATA
EQU
7DH
KEYBOARD NMI SCAN CODE INPUT PORT
NO_HOLD
EQU
OOH
VAL OF P60_HOLD_BYTE FOR NOT Q' 0
NMLSLASH_SC
EQU
4BH
SCAN CODE FOR / MAKE AT NMI LEVEL
P60-AL LSC
EQU
038H
SCAN CODE FOR AL T AT P60 LEVEL
NMLR-AL LBIT3
EQU
08H
USED TO DENOTE LEFT & RIGHT
ALT NMI SC. R-ALT HAS THIS BIT SET.
BREAK-BIT
EQU
BOH
USED TO TST AND SET BRK BIT OF SCs
P60_FILSC
EQU
057H Fll MAKE SC FOR P60
; *******************************************************************
KYBD_PREP - KEYBOARD SCAN CODE NMI PROCESSING
DESCRIPTION:
THIS ROUTINE IS JUMPED TO FROM THE FIRST LEVEL NMI INTERRUPT HANDLER
WHEN THE INTERRUPT IS THE RESULT OF A KEYSTROKE. A CLICK IS SOUNDED
WHEN A KEY SCAN CODE 'MAKE' IS RECEIVED AND THE CLICK STATE IS ON.
THE SCAN CODE IS READ THEN TESTS ARE MADE TO SEE IF THE BUFFER IS
EMPTY AND PORT 60 IS NOT ACTIVE. I F THESE 2 CONDITIONS ARE MET A CALL
IS MADE TO THE XLATE ROUTINE WITH THE KEY SCAN CODE IN AL. ELSE THE
SCAN CODE IS BUFFERED IN THE 16 POSITION NMI SCAN CODE BUFFER AT THE
BUFFER TAIL. IF PORT 60 IS NOT ACTIVE A CALL IS MADE TO THE XLATE
ROUTINE WITH THE KEY SCAN CODE TO BE TRANSLATED AT THE BUFFER HEAD.
THE FIRST LEVEL NMI INTERRUPT HANDLER SAVES REGISTERS AND MOVES THE
ADDRESS OF "DATA" TO THE OS REGISTER BEFORE IT JUMPS TO THIS ROUTINE.
ON EXIT THE FIRST LEVEL INTERRUPT HANDLER RESTORES REGISTERS.
INPUT: DATA IN PORT 7DH
OS = DATA (40H)
OUTPUT: STORE SCAN CODE INTO KB_NMLBUFFER
UPDATE KB_NMLHEAD _TAIL
SAVE LASLCLICK-KEY
INTERNAL ROUTINES: KYBD_XLT
EXTERNAL ROUTINES: SPKILON, KLNO I SE, SPKR_RESTORE
REGISTERS MODIFIED: N/A
INTERRUPTS: LEFT AS ARE
KYBD NMI INITIALLY DISABLED, ENABLED BEFORE EXIT
NORMAL EXIT: JMP NMIH_EXIT
; *******************************************************************
ASSUME
ASSUME
PUSH
POP
PREPI0:
OS: DATA
ES: DATA
DS
ES
NEAR
DATA POINTER TO ES
ENABLE DISPLAY I F DISABLED BY KEYBOARD INACTIVITY
0261
F6 06 0016 R 80 TEST
JZ
BIOS_STATUS,DSP_BLANKED ; IS LCD BLANKED?
PREP _12 0266 74 OF
,
; RESET BLANKED FLAG AND ENABLE DISPLAY
ROM BIOS 2-35