IBM 5150 - Page 143

LOC OBJ
LINE SOURCE
1508
1509
1----- IPL MAS SUCCESSFUL
1510
E6E4
1511
H4:
E6E4 £A007COOOO
1512
JMP
BOOT_lOCN
E6F2
1513 OIlG OE6F2H
E~F2
1514
eOOT_STRAP
PROC
NEAR
E6Ft: FB
1515 sn
I ENABLE INTERRUPTS
Eon ZBCO
1516 SUB AX.AX
EoF5 8E08
1517 I10V
DS.AX
1518
1519
1----- RESET DISKETTE PARAMETER TABLE VECTOR
1520
EoF7 C7067800C7EF
1521 MOV
WORD PTR DISK_POINTER, OFFSET DJ:SK_BASE
E6FD 8COE7AOO
1522
HOV WORD PTR DISK_POINTER-t2,CS
E701
All004 1523 MOV AX,DATA_WORO[ OFFSET EQUIP_flAG J 1 GET THE EQUIPMENT SWITCHES
E704 A801
152:4 TEST AL,l I ISOLATE IPL SENSE SWITCH
£106 741E
15"
JZ HJ
; GO TO CASSETTE BASIC EHTRY POINT
1526
152:7
1----- MUST LOAD SYSTEM FROf1 DISKETTE -- CX HAS RETRY COUNT
1528
E708 890400
1529
MOV
CX,4 I SET RETRY COUNT
E70B
1530
HI:
; IP __ SYSTEtI
E70B 51
1531 PUSH
CX
I SAVE RETRY COUNT
E70e B40D
1532 MOV AH,O I RESET THE DISKETTE SYSTEM
E70E con 1533
INT lJH
; DISKETTE_IO
E710 720F
1534 JC H2
; IF ERROR., TRY AGAIN
E712 B80102
1535 MOV AX,20iH I READ IN THE SINGLE SECTOR
E715 2802
1536
SUB OX,DX
E717 8EC2 1537
MOV ES,DX
E719 BBDD7C
1538 HOV BX,OFFSET BOOT_LOCH
E7IC 890100
1539
MOV
CX ••
I SECTOR 1, TRACK a
E71F con
1540
INT
lJlt
i DISKETTE_IO
E721 59
1541
H2 :
POP CX I RECOVER RETRY COUNT
E722 nco
1542
JNC
H'
I CF SET BY UNSUCCESSFUL READ
£724 E2:E5
1543 LOOP
HI
1 DO IT FOR RETRY TIMES
1544
1545 1----- lR-IABLE TO IPL FROI'1 THE DISKETTE
15"
£726
1547
H3:
1 CASSETTE_JU1P:
E7t6 COIS
1548
INT
18H
i USE INTERRUPT VECTOR TO GET TO BASIC
154q
1550
1551
1----- INT 14----- - - - - - - -------------------- - - ----- - -- - - - - - - - - - ---- - - - - ---
1552 1 RS232_IO
1553 I THIS ROUTINE PROVIDES BYTE STREAM 1/0 TO THE COMt1UNICATIONS
1554 PORT ACCORDING TO THE PARAMETER'S:
1555
(AH )=0 INITIALIZE THE COMMUNICATIONS PORT
1556 IAU HAS PARAMETERS FOR INITIALIZATION
1557
1558 2
1559
----- BAli) RATE --
-PARITY-- STOPSIT --WORD LENGTH--
1560
ODD - no XO - HONE
a - 1 10 - 7 BITS
1561
001 - 150 01 - 000
1 - 2 11 - 8 BITS
1562
OlD - 300 11 - EVEN
1563
011 - 600
1564
100 - 1200
1565
101 - 2400
1566
110 - 4800
1567 III - 9600
1568
1569 ON RETURN, COt-lJITIOHS SET AS IN CALL TO COMMO STATUS (AH=3)
1570
(AH)=1
SEND THE CHARACTER IN tAL) OVER THE COMMO LINE
1571 (AU REGISTER IS PRESERVED
1572 ON EXIT, BIT 7 OF AH IS SET IF THE ROUTINE WAS UNABLE
1573
TO TRAHSI1IT THE BYTE OF DATA OVER THE LINE.
1574
IF BIT 7 OF AH IS HOT SET, THE REMAINDER OF AH
1575 IS SET AS IN A STATUS REQUEST. REFLECTING THE
1576
CURRENT STATUS OF THE LINE.
1577
(AHJ=2 RECEIVE A CHARACTER IN (AU FROM COMMO LINE BEFORE
1578 RETURNING TO CALLER
1579
ON EXIT. AH HAS THE CURRENT LINE STATUS. AS SET BY THE
1580
THE STATUS ROUTINE, EXCEPT THAT THE ONLY BITS
1581
LEFT
ON ARE THE ERROR BITS 17,4,3,2,1)
1582
IF AH HAS BIT 7 ON (TIME OUll THE REMAINING
1583
BITS ARE NOT PREDICTABLE.
1584
THUS, AH IS NOH ZERO ONLY WHEN AN ERROR
5-50 System BIOS