IBM 5150 PC Technical Reference (6025005, August, 1981) (PDF)

LOC 08J LINE SOURCE
2255 ;-- INT 13 ---------------------'------------­
2256 ;DISKETTE 1/0
2257 THIS INTERFACE PROVIDES ACCESS TO THE 5 1/4" DISKETTE DRIVES
2.258 ; INPUT
2259 (AH };;Q RESET DISKETTE SYSTEM
2260 HARD RESET TO NEC, FREPARE COMMAND. RECAL REQD ON ALL DRIVES
2261 (AHI=l READ THE STATUS OF THE SYSTEM INTO (All
2262 DISKETTE_STATUS FROM LAST OP'" IS USIO
2263 REGISTERS FOR P.EAO/WRITE/vERIFY/FORMAT
2264 (OLI - DRIVE NUtlBER (0-3 ALLOWED, VALUE CHECKED)
22:65 {DHI ~ HEAD ~ruMBER (0-1 ALLOWEn, I\'OT VALUE CHECKED)
2266 (CH) - TRACK NUtlBER (0-39, t.'OT VALUE CHECKEO)
22:67 (eL) - SECTOR truMBER f 1-8, NOT VALUE CHECKEO)
2268 fAll - NUMBER OF SECTORS ( MAX ;; 8, NOT VALUE CHECK EO)
2269
2270 (ES:BX) - ADDRESS OF BUffER ( NOT REQUIRED FOR VERIFY)
2:271
2272 (AH )=2: READ THE DESIRED SECTOOS INTO MEMORY
2273 «AH )=3 WRITE HlE DESIRED SECTORS FROM HEMORY
2274 (AH 1=4 VERIFY THE DESIRED SECTORS
22:75 (AH);:5 FORMAT THE DESIRED TRACK
2276 FOR THE fORMAT OPERATlm" THE BUFFER POINTER (ES,BXI MUST
2277 POINT TO THE COLLECTIOH OF DfSIRED ADDRESS FIElDS FOR THF.:
22:78 TRACK. EACH FIELD IS CQtlPOSED OF 4 BYTES. (C,H,R,NI, WHERE
2279 C ;; TRACK HUMBER, H=HEAD NUMBER, R ;; SECTOR NUMBER, N= NUMBER
2280 OF BYTES PER SECTOR ("00=128, 01=256, 02=512. 03=1024,)
2281 THERE MUST BE ONE ENTRY FOR EVERY SECTOR ON THE TRACK.
USZ
2:283 READ/WRITE ACCESS.
2284 ; DATA VARIABLE -­ DISK_POINTER
THIS INFORMATION IS USED TO Fum THE REQUESTED SECTOR DURING
~28S DOUBLE WORD POINTER TO THE CURRENT SET OF DISKETTE PARAMETERS
2286 ; OUTPUT
2287 AH = STATUS OF OPERATION
2288 STATUS BITS ARE DEfINED IN THE EQUATES fOR DISKETTE_STA,TUS
2289 VARIABLE IN THE DATA SEGMENT OF THIS NODULE
EC59
EC59 fB
ECSA 53
Ee58 51
ECSC IE
Ee50 56
ECSE 57
ECSF 55
EC60 52
EC61 8BEt
EC63 8E4000
EC66 BEDf
EC68 f81COO
EC6B 6B0400
EC6E ESFFO}
Ee7l e8264000
Ee75 8A264100
EC79 80FCO)
Ee7t FS
EC7D SA
Ee7E 50
[e7F SF
EC8Q Sf
EC8l IF
Ee62 59
Ecel 58
E(84 CA0200
Ee87
2290
2291
2292
2293
2294
2295
2296
2297
2296
2299
2300
2301
2302
2303 PROC FAR
2304
2]05 ex
2306 ex
2307 os
2308 51
Z309 01
2310 BP
2311 ox
2312 BP.SP
e313
SI,DATA
2314 OS,SI
2315 Jl
2316 BX,4
2317
2318
2319
2320 eMP AH,J ; SET THE CARRY fLAG TO INDICATE
2321 eMe I SUCCESS OR FAILURE
2322 POP ox i RESTORE ALL REGISTERS
232:3 POP BP
2324 POP 01
2325 POP 51
2326 POP OS
2327 POP CX
2328 POP BX ; RECOVER ADDRESS
2329 RET ; THROW AWA'( SAVED FLAGS
2330 DISKETTE_IO E~mp
2:331 Jl PROC ~lEAR
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