IBM PC CONVERTIBLE Technical Reference page 160

041B
MOTOILSTARTUP
FUNCTION: TO CHECK FOR MOTOR STATE, TURN ON MOTOR OF REQUESTED DRIVE
AND WAIT THE NECESSARY STARTUP TIME BEFORE RETURNING
TO CALLER.
I NPUT PARAMETERS:
DL = 0-3 (DISKETTE DRIVE NUMBER)
OUTPUT PARAMETERS:
MOTOILSTATUS FLAGS UPDATED
MOTOR OF DRIVE IS TURNED ON
REGISTERS MODIFIED: AX,BX,CX,DH
MOTOILSTARTUP PROC NEAR
;----- TURN ON THE MOTOR AND SELECT THE DRIVE
041B B6 00
041D
MOV
MOL01:
DH,O ; SET FIRST TIME THROUGH FLAG
GET MOTOR STARTUP TI ME
0410 BB 0014 MOV BX,20 GET THE MOTOR WAIT
0420 E8 0259 R CALL GELPARM CH HAS MOTOR START UP DELAY
0423 80 FC 04 CMP AH,04 MUST BE MINIMUM OF 500 MSECS
0426 73 02 JAE MOLOn JUMP IF OKAY
0428 B4 04 MOV AH,04 DEFAULT TIME TO 500 MSECS
042A MOLOll:
042A 8A EC MOV CH,AH SAVE MOTOR START UP DELAY
042C 8A CA MOV CL,DL GET DRIVE NUMBER AS SHIFT COUNT
042E BO 01
MOV AL,l
MASK FOR DETERMINING MOTOR BIT
0430 D2 EO
SAL AL,CL
SHI FT THE MASK BIT
0432 FA
CLI
NO INTERRUPTS WHILE DETERMINING
MOTOR STATUS
0433 84 06 003F R
TEST
AL ,MOTOR_STATUS TEST THAT MOTOR FOR OPERATING
0437 75 IB
JNZ MOL02
IF RUNNING GO CHECK TIME
; TURN ON MOTOR
0439 80 26 003F R FO AND MOTOR_STATUS,OFOH TURN OFF ALL MOTOR BITS
043E 08 06 003F R OR MOTOILSTATUS, AL TURN ON THE CURRENT MOTOR
0442 BO 10 MOV AL,10H MASK BIT
0.4.44 8A CA MOV CL,DL GET DRIVE NUMBER AS SHI FT COUNT
0446 D2 EO SAL AL,CL DEVELOP BIT MASK FOR MOTOR ENABLE
0448 OA C2 OR AL,DL ; GET DRIVE SELECT BITS IN
044A
OC OC
OR
AL,FDCDMILENAB+FDCRUN ; NO RESET, ENABLE DMA/INT
044C 52 PUSH DX SAVE REG
044D BA 03F2 MOV DX,DRIVE_CNTL CONTROL PORT ADDRESS
0450 EE OUT DX,AL
0451 5A POP DX RECOVER REGISTERS
0452 EB 07 JMP SHORT MOL04 GO DELAY FOR STARTUP
CHECK TO SEE I F MOTOR ON LONG ENOUGH
0454
MOL02:
0454 F6 06 003F R 20
0459 75 24
TEST
JNZ
MOTOILSTATUS,MOTOILOK ; CHECK FOR MOTOR RUNNING LONG ENOUGH
MOL08 IF MOTOR OKAY THEN EXIT
,
; CH HAS TIME TO WAIT IN 1/8 SECONDS
045B MOL04:
045B
C6 06 0040 R FF MOV MOTOILCOUNT,OFFH SET LONG MOTOR DELAY
0460 FB
STI I NTERRUPTS BACK ON
0461 OA ED
OR CH,CH
DON'T WAIT IF NO WAIT SET
0463 74 1A
JZ MOL08
0465 OA F6
OR DH,DH
CHECK FOR FIRST TIME THROUGH WAIT
0467 75 08
JNZ MOL06
I F NOT FIRST TIME BYPASS OP _SYS HOOK
NOTIFY OPERATING SYSTEM OF WAIT FOR MOTOR STARTUP
0469 F8 CLC ; RESET TIMEOUT INDICATOR
ROM BIOS 2-135