IBM XT 5160 - Page 205

IBM Personal Computer MACRO Assembler Version 2.00
PRT ------ 01/10/86 PRINTER ADAPTER BIOS
1-2
01-10-86
B45:
WA I T BUSY
B50:
PAGE
FUNCT I ON 90 PR I NTER 10
SYSTEM CALL
SAVE CALLER S ( CX) REG I STER
I NNER LOOP
(64K)
GET STATUS
STATUS
TO (AHI ALSO
I S THE PR INTER CURRENTLY BUSY
GO TO OUTPUT STROBE
LOOP
IF NOT
DECREMENT OUTER LOOP COUNT
MAKE ANOTHER PASS I F NOT ZERO
RESTORE
(CX) WITH CALLERS VALUE
SET ERROR FLAG
TURN OFF THE UNUSED BITS
RETURN WITH ERROR FLAG SET
SEND STROBE PULSE
RESTORE (CX) WITH CALLERS VALUE
SET THE STROBE LOW (B I T ON)
OUTPUT STROBE TO CONTROL PORT
PREVENT I NTERRUPT PULSE STRETCH I NG
OUTPUT STROBE BIT > 1 us < 5us
I /0 DELA Y TO ALLOW FOR LINE LOAD I NG
AND FOR CORRECT PULSE WIDTH
SET THE - STROBE HIGH
I NTERRUPTS BACK ON
ADJUST BACK TO BASE ADDRESS
FOR
STATUS ROUTINE EXIT
NO INTERRUPTS, NON AUTO LF, I NIT HIGH
SET DEFAULT I N I TI AL OUTPUTS
ADJUST BACK TO BASE ADDRESS
FOR
STATUS ROUT I NE EX I T
EX I T THROUGH
STATUS ROUT I NE
RECOVER CHARACTER
INTO (AL) REG I STER
FLI P A COUPLE OF BITS I N STATUS
RETURN FROM ROUT I NE WITH STATUS IN AH
; PO I NT TO OUTPUT PORT
SET INIT LINE LOW
ADJUS T FOR I NIT I ALI ZA TI ON DEL AY LOOP
DECREMENT
DELAY COUNTER
LOOP FOR
RESET TO TAKE
; PO I NT TO CONTROL PORT
PRE-CHARGE +BUSY LINE IF FLOATING
GET PR I NTER STATUS HARDWARE BITS
TURN OFF UNUSED BITS
SAVE
;
PRE-CHARGE +BUSY LINE IF FLOATING
GET STATUS PORT VALUE
I S THE PR INTER CURRENTLY BUSY
SK I P SYSTEM DEV I CE BUSY CALL I F NOT
AX
B90
AL,OCH
DX,AL
OX
OX
B60
ENDP
ENDS
I N I
TI ALI ZE THE PR I NTER PORT
MOV
OUT
DEC
DEC
JMP
INC OX
IN AL,DX
IN AL,DX
AND AL,OF8H
MOV AH,AL
MOV AL,BH
XOR AH,48H
JMP B20
INC OX
INC OX
MOV AL,8
OUT DX,AL
MOV AX, 1000
DEC
JNZ
PR I NTER STATUS
PUSH CX
SUB CX,CX
IN AL,DX
IN AL,DX
TEST AL,80H
JNZ B40
I NT 15 H - - DEV I CE BUS Y
IN AL,DX
MOV AH,AL
TEST AL,80H
JNZ B50
LOOP B45
DEC BL
JNZ B45
CHECK FOR PR I NTER BUSY
MOV AX, 90FEH
INT 15H
POP CX
OR AH,I
AND AH,OF9H
JMP SHORT B70
MOV AL,OCH
OUT DX,AL
STI
DEC OX
DEC OX
POP CX
MOV AL,ODH
INC OX
CLI
OUT DX,AL
JMP S+2
B80:
B70:
B90:
PR INTER_IO_1
CODE
END
B60:
B40:
96
97
98
99
0034 EC
100 0035 EC
101
0036 A8 80
102 0038 75 05
103
104
105
106 003A B8 90FE
107 0030 CD 15
108
109
I 10
I II 003F
112 003F 51
1
13 0040 2B C9
114 0042
115 0042 EC
1
16 0043 8A EO
1 17 0045 A8 80
I 18 0047 75 OF
119
120 0049 E2 F7
121
122 004B FE CB
123 0040 75 F3
124
125 004F 59
126 0050 80 CC 0 I
127 0053 80 E4 F9
128 0056 EB 15
129
130 0058
131 0058 59
132 0059 BO 00
133 005B 42
134 005C FA
13~ 0050 EE
136 005E EB 00
137
138
0060 BO OC
139 0062 EE
140 0063 FB
141 0064 4A
142 0065 4A
143
144
145
146
147
0066
148 0066 42
149 0067 EC
150 0068 EC
151
0069 24 F8
152 006B 8A EO
153 0060
154 0060 8A C7
155 006F 80 F4 48
156 0072 EB BB
157
158
159
160
161 0074
162 0074 42
163 0075 42
164 0076 BO 08
165 0078 EE
166 0079 B8 03E8
167 007C
168 007C 48
169 0070 75 FD
170
171 007F BO OC
172 0081 EE
173 0082 4A
174 0083 4A
175 0084 EB EO
176
177 0086
178
179 0086
180
5-58
PRINTER
(01/10/86)