IBM XT 5160 Technical Reference page 233

IBM Personal Computer MACRO Assembler Version 2.00
POST ----- 01/10/86 SYSTEM POST AND BIOS PROCEDURES
1-3
01-10-86
PAGE
; ----- WRAP DMA CHANNELS ADDRESS AND COUNT REG I STERS
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8237 DMA I N IT I ALI ZATI ON CHANNEL REG I STER TEST
DESCR I PT I ON
o
I SABLE THE 8237 DMA CONTROLLER. VER I FY THAT
T I MER I FUNCT IONS OK. WR I TE / READ THE CURRENT
ADDRESS AND WORD COUNT REG I STERS FOR ALL
CHANNELS. I NIT I AL I ZE AND START DMA FOR MEMORY
REFRESH.
<> <> <> <> <> <> <> <> <> <> <> <>
<><><>CHECKPO I NT 2<><><>
o
I SABLE DMA CONTROLLER
SEL TIMER I.LSB.MODE 2
SET I N IT I AL T I MER CNT TO 0
T I MER I BITS ON
LATCH TIMER-l COUNT
YES - SEE IF ALL BITS GO OFF
TIMER 1 BITS OFF
READ TTMER
T
COUNT
ALL BITS ON IN TIMER
TlMERl BITS ON
TIMER
T
FAILURE. HALT SYS
TIMERI BITS OFF
SET TIMER I-CNT
TIMER LOOP
LA TCH-T I MER I COUNT
DELA Y FOR T I MER
READ T I MER I COUNT
WRAP DMA REG
TIMER LOOP
HALT SYSTEM
SET CNT OF 64K FOR REFRESH
SET DMA MODE. CH O. RD •• AUOT I NT
WR I TE DMA MODE REG
ENABLE DMA CONTROLLER
SET COUNT HIGH=OO
SETUP DMA COMMAND REG
ENABLE DMA CH 0
START TIMER 1
; SET MODE FOR CHANNEL I
GET DMA STATUS
IS TIMER REQUEST THERE?
(IT SHOULD'T BE)
HALT SYS. (HOT TIMER I OUTPUT)
SET MODE FOR CHANNEL 2
; SET MODE FOR CHANNEL 3
; SET UP ABSO I NTO OS AND ES
WR I TE PATTERN FF TO ALL REGS
SAVE PATTERN FOR COMPARE
SETUP LOOP CNT
SETUP I /0 PORT ADDR OF REG
WRITE PATTERN TO REG, LSB
SATISIFY 8237 I/O TIMINGS
MSB OF 16 BIT REG
AL TO ANOTHER PAT BEFORE RD
READ 16-BIT DMA CH REG. LSB
SAVE LSB OF 16-B I T REG
READ MSB OF DMA CH REG
PATTERN READ AS WR I TTEN?
YES - CHECK NEXT REG
; NO - HALT THE SYSTEM
; NXT DMA CH
; SET-I /O-PORT TO NEXT CH REG
; WR I TE PATTERN TO NEXT REG
; I F CARRY NOT SET HALT SYSTEM
SET PATTERN TO 0
; WR I TE TO CHANNEL REGS
; <><><><><><><><><><><><>
; <><><>CHECKPO I NT 3<><><>
; WRAP DMA REG
; SEND-MASTER CLEAR TO DMA
AL.54H
TIMER+3.AL
AL.CL
TIMER+ I .AL
OX
CI7
CI7A
AL
CI6
AL,42H
DMA+OBH.AL
AL.43H
DMA+OBH.AL
DS,BX
ES.BX
OS: ABSO. ES: ABSO
AL.OFFH
DMA+ 1 .AL
AX
DMA+ I .AL
AL.058H
DMA+OBH.AL
AL.O
CH.AL
DMA+8.AL
AX
DMA+ I O.AL
AL.18
TIMER+ 1 .AL
AL.4IH
DMA+OBH.AL
AX
AL.DMA+08
AL. 000 1OOOOB
C18C
AL.02H
PORT A.AL
AL.04
DMA08.AL
AL.03H
PORT_A,AL
DMA+ODH.AL
AL.OFFH
BL.AL
BH.AL
CX.8
DX.DMA
DX.AL
AX
DX.AL
AL.OIH
AL.DX
AH.AL
AL.DX
BX.AX
CI8
MOV
OUT
OUT
MOV
MOV
MOV
MOV
MOV
OUT
PUSH
OUT
MOV
IN
MOV
IN
CMP
JE
HLT
INC
STC
LOOP
JNC
INC
JZ
MOV
MOV
ASSUME
MOV
OUT
PUSH
OUT
MOV
OUT
MOV
MOV
OUT
PUSH
OUT
MOV
OUT
MOV
OUT
PUSH
IN
AND
JZ
HLT
MOV
OUT
MOV
OUT
MOV AL.40H
OUT T I MER+3. AL
CMP BL ,OFFH
JE CI3
I N AL , T I MER + I
OR BL,AL
LOOP C12
HLT
MOV
OUT
MOV
OUT
MOV
OUT
MOV
OUT
MOV AL ,BL
SUB CX,CX
OUT T I MER + 1 ,AL
MOV AL,40H
OUT T I MER+3, AL
NOP
NOP
I N AL , T I MER + 1
AND BL,AL
JZ C15
LOOP CI4
HLT
I N I TI ALI ZE AND START DMA FOR MEMORY REFRESH.
I NIT I AL I ZE T I MER 1 TO REFRESH MEMORY
VER I FY THAT T I MER I FUNCT IONS OK
; - - - - - 0 I SABLE DMA CONTROLLER
C16:
CI8C:
C18:
C15:
CI7A:
C14:
C17:
C13:
C12:
228
229
230
231
232
233
234
235
236
237
238
239
240
241 0007 BO 02
242 0009 E6 60
243 OODB BO 04
244 0000 E6 08
245
246
247
248 OODF BO 54
249 OOE I E6 43
250 00E3 8A C 1
251 00E5 E6 41
252 00E7
253 00E7 BO 40
254 00E9 E6 43
255 OOEB 80 FB FF
256 OOEE 74 07
257 OOFO E4 41
258 00F2 OA 08
259 00F4 E2 F I
260 00F6 F4
261 00F7
262 00F7 8A C3
263 00F9 2B C9
264 OOFB E6 41
265 OOFD
266 OOFD BO 40
267 OOFF E6 43
268 010 I 90
269 0102 90
270 0103 E4 41
271 0105 22 08
272 0107 74 03
273 0109 E2 F2
274 01 OB F4
275
276
277
278 010C BO 03
279 010E E6 60
280
28 I 01 10 E6 00
282
283
284
285 0 I 12 BO FF
286 01 14 8A 08
287 01 16 8A F8
288 01 18 B9 0008
289 01 I B BA 0000
290 0 liE EE
291 011 F 50
292 0120 EE
293 0 I 21 BO 0 I
294 0123 EC
295 0124 8A EO
296 0126 EC
297 0127 3B 08
298 0129 74 01
299 012B
300 012B F4
301 012C
302 012C 42
303 0120 F9
304 012E E2 EE
305 0130 73 F9
306 0 I 32 FE CO
307 0134 74 DE
308
309
310
31 I 0136 8E DB
312 0 I 38 8E C3
313
3 I 4 0 I 3A BO FF
3 I 5 0 I 3C E6 0 1
316 013E 50
3 1 7 0 13F E6 0 I
318 0141 BO 58
3 19
0 I 43 E6 OB
320 0145 BO 00
321 0147 8A E8
322 0 I 49 E6 08
323 014B 50
324 01 4C E6 OA
325 01 4E BO 12
326 0 I 50 E6 41
327 0152 BO 41
328 0 I 54 E6 OB
329 0156 50
330 0157 E4 08
331 0159 24 10
332 015B 74 0 I
333 0150 F4
334 0 I 5E BO 42
335 0 I 60 E6 OB
336 0 I 62 BO 43
337 0164 E6 OB
5-86 POST (01/10/86)