IBM PC CONVERTIBLE Technical Reference page 159

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EC
A8 40
75 07
80 DE 0041
EB FO
42
EC
88 04
46
B9 OOOA
E2 FE
4A
EC
A8 10
74 06
FE CB
75 CB
EB E3
5A
59
C3
BB 0008
E8 0259 R
AO 0047 R
8A 7E 01
J40A:
IN AL,DX GET STATUS REG AGAIN
TEST
AL,DATA_READY
TEST DIRECTION BIT
JNZ J42 OK TO READ STATUS
J41 : ; NECFAIL
R 20 OR DISKETTE_STATUS, BAD_NEC
JMP J40
; RESULTS_ERROR
READ IN THE STATUS
J42: INPULSTAT
INC OX POINT AT DATA PORT
IN AL,DX GET THE DATA
MOV [SI] ,AL STORE THE BYTE
INC SI INCREMENT THE POINTER
MOV CX,10 LOOP TO KILL TIME FOR NEC
J43: LOOP J43
DEC OX POINT AT STATUS PORT
IN AL,DX GET STATUS
TEST AL, FDCBUSY TEST FOR NEC STI LL BUSY
JZ J44 RESULTS DONE
DEC BL DECREMENT THE STATUS COUNTER
JNZ J38 GO BACK FOR MORE
JMP J41 CHIP HAS FAILED
RESUL T OPERATION I S DONE
J44:
POP OX
POP
CX RECOVER REGI STERS
RET GOOD RETURN CODE FROM TEST
RESUL TS ENDP
NUM_TRANS
THIS ROUTINE CALCULATES THE NUMBER OF SECTORS THAT
WERE ACTUALLY TRANSFERRED TO/FROM THE DISKETTE
INPUT
(BP)
=
POINTER TO ORIGINAL STACK ENTRIES
OUTPUT
(BP+14)
=
AL SAVE AREA ON STACK
=
#
ACTUALLY TRANSFERRED
NO OTHER REGISTERS MODIFIED
NUM_TRANS PROC NEAR
MOV
BX,8 SECTORS/TRACK OFFSET TO DL
CALL
GELPARM AH
=
SECTORS/TRACK
MOV AL,NECSTATUS+5 GET ENDING SECTOR
MOV BH, DHSAVE [BP] BH
=
STARTING HEAD #
INST
3A 3E 0046 R CMP BH,NECSTATUS+4 GET HEAD ENDED UP ON
75 DB JNZ
01 F _HD
I F ON SAME HEAD, THEN NO ADJUS
8A 3E 0045 R MOV BH,NECSTATUS+3 GET TRACK ENDED UP ON
3A 7 E DB
CMP BH,CHSAVE[BP] SEE I F TRACK SWITCH
74 04 JZ
SAME_TRK
IF SAME TRACK NO INCREASE
02 C4 ADD AL,AH ADD SECTORS/TRACK
DIF_HD:
02 C4 ADD AL,AH ADD SECTORS/TRACK
SAMLTRK:
2A 46 OA SUB AL, CLSAVE [BP] SUBTRACT START FROM END SECTORS
88 46 DE MOV ALSA VE [BP] ,AL SAVE RESULTS IN STACK SAVE AREA
C3 RET
NUM_TRANS
ENDP
2-134 ROM BIOS