Atari 400 Technical Reference Manual page 293

ERR LINE ADDR Bl B2 B3 B4 INTERRUPT HANDLER
PAGE
32
1315 E724 DO 04 BNE LooPM2
1316 E726 25 10
AND PoKMSK i IS THIS INTERUPT ENABLED?
1317 E728 FO 05
BEG LL
1318
E72A
2C OE D2 LOOPM2: BIT IRGST i IS IT THE INTERUPT?
1319 E72D FO 06 BEG JMPP
1320 E72F CA
LL:
OEX
iNa
DEC x AND TRY NEXT MASK
1321 E730 10 ED
BPL LOOPM
i
IF NOT NEG GOTO LOOPM
1322 E732 4C 62 E7 JMP SYIRG8 iDONE BUT NO INTERUPT
1323 E735 49 FF JMPR: EaR #$FF iCoMPLEMENT MASK
1324 E737 8D OE D2 STA IRGEN iENABLE ALL OTHERS
1325 E73A
AS 10 LDA POKMSK GET POKE MASK
1326
E73C
80 OE 02 STA IRGEN ENABLE THOSE IN POKE MASK
1327 E73F BD FE E6 LDA ADRTAB,X
1328 E742 AA TAX
1.329
E743
BD 00 02 LOA
INTABS,X
GET ADDRESS LOW PART
1330 E746 80 8C 02 STA JVECK PUT IN VECTOR
1331
E749
BD 01 02 LDA INTABS+1,X GET ADDRESS HIGH PART
1332 E74C 80 80 02 STA JVECK+l PUT IN VECTOR HIGH PART
1333 E74F 68 PLA PULL X REGISTER FROM STACK
1334 E750 AA TAX PUT IT INTO X
1335 E751 6C 8C 02 JMP (JVECK)
JUMP TO THE PROPER ROUTINE
1336 E754
A9 00 BRKKY2: LOA
#0
BREAK KEY ROUTINE
1337 E756 85 11 STA BRKKEY SET BREAK KEY FLAG
1338 E758 80 FF 02 STA SSFLAG START/STOP FLAG
1339 E75B 80 FO 02 STA CRSINH CURSOR INHIBIT
1340 E75E 85 40 STA ATRACT
TURN OFF ATRACT MODE
1341 E760
68 PLA
1342 E761 40
RTI
i
EX IT FROM INT
1343 E762 68 SYIRG8: PLA
1344 E763 AA TAX
1345 E764 2C 02 03
BIT PACTL iPROCEED ***I GUESS***
1346 E767
10 06 BPL SYIRG9
1347 E769 AD 00 03 LOA PORTA CLEAR INT STATUS BIT
1348 E76C 6C 02 02 JMP (VPRCED)
1349 E76F 2C 03 D3 SYIRG9: BIT
PBCTL
i
INTERRUPT ***1 GUESS***
1350 E772 10 06 BPL SYIRGA
1351
E774
AD 01 D3 LDA PoRTB
iCLEAR INT STATUS
1352 E777 6C 04 02 JMP (VINTER)
1353 E77A 68 SYIRGA: PLA
1354 E77B
80 8C 02 STA JVECK
1355
E77E
68 PLA
1356 E77F 48 PHA
1357 E780 29 10 AND
#$10
iB
BIT OF P REGISTER
1358 E782
FO 07 BEG SYRTI2
1359 E784 AD 8C 02 LDA JVECK
1360 E787 48 PHA
1361 E788 6C 06 02
JMP
(VBREAK)
1362
E78B
AD 8e 02 SYRTI2: LDA JVECK
1363 E78E 48 PHA
1364 E78F 68 SYIRGB: PLA
1365 E790
40 SYRTI: RTI iUNIDENTIFIED INTERRUPT, JUST RETURN.