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7af5ad59 PH |
1 | /FLOPPY DISK (RX01,RX71) NON-SYSTEM HANDLER FOR OS/8 |
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11 | /COPYRIGHT (C) 1977 BY DIGITAL EQUIPMENT CORPORATION | |
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22 | /THE INFORMATION IN THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE | |
23 | /AND SHOULD NOT BE CONSTRUED AS A COMMITMENT BY DIGITAL EQUIPMENT | |
24 | /CORPORATION. DIGITAL EQUIPMENT CORPORATION ASSUMES NO RESPONSIBILITY | |
25 | /FOR ANY ERRORS THAT MAY APPEAR IN THIS DOCUMENT. | |
26 | / | |
27 | /THE SOFTWARE DESCRIBED IN THIS DOCUMENT IS FURNISHED TO THE PURCHASER | |
28 | /UNDER A LICENSE FOR USE ON A SINGLE COMPUTER SYSTEM AND CAN BE COPIED | |
29 | /(WITH INCLUSION OF DIGITAL'S COPYRIGHT NOTICE) ONLY FOR USE IN SUCH | |
30 | /SYSTEM, EXCEPT AS MAY OTHERWISE BE PROVIDED IN WRITING BY DIGITAL. | |
31 | / | |
32 | /DIGITAL EQUIPMENT CORPORATION ASSUMES NO RESPONSIBILITY FOR THE USE | |
33 | /OR RELIABILITY OF ITS SOFTWARE ON EQUIPMENT THAT IS NOT SUPPLIED BY | |
34 | /DIGITAL. | |
35 | / | |
36 | / | |
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44 | / | |
45 | \f/FLOPPY DISK (RX01,RX71) NON-SYSTEM HANDLER FOR OS/8 | |
46 | ||
47 | /DEFINITIONS OF RX8/E IOT'S | |
48 | ||
49 | RXVER= "E&77 | |
50 | ||
51 | DEVCOD= 750 /DEVICECODE | |
52 | ||
53 | LCD= 6001+DEVCOD /LOAD COMMAND REGISTER | |
54 | XDR= 6002+DEVCOD /TRANSFER DATA REGISTER | |
55 | STR= 6003+DEVCOD /SKIP ON TRANSFER REQUEST FLAG, CLEAR FLAG | |
56 | SER= 6004+DEVCOD /SKIP ON ERROR FLAG, CLEAR FLAG | |
57 | SDN= 6005+DEVCOD /SKIP ON DONE FLAG, CLEAR FLAG | |
58 | INTR= 6006+DEVCOD /INTERRUPT ENABLE/DISABLE | |
59 | INIT= 6007+DEVCOD /INITIALIZE CONTROLLER AND RECALIBRATE DRIVES | |
60 | ||
61 | ||
62 | /NOTES ON THIS HANDLER: | |
63 | ||
64 | /THIS HANDLER READS AND WRITES THE DISK IN "12-BIT" MODE, IN WHICH | |
65 | /ONLY 6 BITS OF EVERY 8-BIT BYTE ARE USED. AN RX01 CARTRIDGE | |
66 | /CONTAINS 494 OS/8 BLOCKS UNDER THIS METHOD | |
67 | ||
68 | /TO MAXIMIZE SPEED ON THE DEVICE, THE HANDLER READS AND WRITES DATA | |
69 | /ON A TRACK WITH A TWO-WAY INTERLEAVE - I.E. RECORDS 1-26 ON A TRACK | |
70 | /ARE WRITTEN IN THE SEQUENCE: | |
71 | / 1,3,5,7,9,11,13,15,17,19,21,23,25,2,4,6,8,10,12,14,16,18,20,22,24,26 | |
72 | ||
73 | /IN THIS WAY THE HANDLER CAN TRANSFER DATA AT A 5KHZ WORD RATE | |
74 | ||
75 | /MODIFIED TO ALLOW ADDRESS CALCULATION DURING SECTOR BUFFER | |
76 | /LOAD-UNLOAD. | |
77 | \f *0 /ORIGIN FOR BUILD | |
78 | ||
79 | -2 /TWO ENTRY POINTS | |
80 | DEVICE RX01 /"RX01" IS THE GROUP NAME | |
81 | DEVICE RXA0 /"RXA0" IS THE ENTRY POINT NAME | |
82 | 4250 /DCB WORD - DEVICE TYPE 25, DIRECTORY DEVICE | |
83 | RXA0&177 /ENTRY POINT OFFSET | |
84 | 0 /THIS WORD ALWAYS SEEMS TO BE 0 | |
85 | 0 /UNUSED FOR NONSYSTEM DEVICE | |
86 | ||
87 | DEVICE RX01 /"RX01" IS THE GROUP NAME | |
88 | DEVICE RXA1 /"RXA1" IS THE ENTRY POINT NAME | |
89 | 4250 /DCB WORD - DEVICE TYPE 25, DIRECTORY DEVICE | |
90 | RXA1&177 /ENTRY POINT OFFSET | |
91 | 0 /THIS WORD ALWAYS SEEMS TO BE 0 | |
92 | 0 /UNUSED FOR NONSYSTEM DEVICE | |
93 | \f *200 /HANDLER CODE | |
94 | ||
95 | BUF, 0 /USER BUFFER POINTER | |
96 | REC, 0 /RX01 RECORD NUMBER BEFORE INTERLEAVING | |
97 | BC, 0 /BLOCK COUNT OF TRANSFER | |
98 | FN, 0 /FUNCTION, 0=WRITE, 2=READ | |
99 | TRANS, 0 /TRANSFER COMMAND | |
100 | ||
101 | FLPWC=. /100 COUNTER FOR SILO OK IN LDCMD ENTRY | |
102 | LDCMD, 0 /WAIT FOR DONE FLAG AND LOAD CMD REG | |
103 | DCA TRANS /SAVE THE NEW COMMAND REG VALUE | |
104 | DONELP, TAD S7600 /SEE IF THE KEYBOARD BUFFER | |
105 | KRS /CONTAINS A CONTROL/C CHARACTER | |
106 | TAD (-7603 /(WITH OR WITHOUT PARITY) | |
107 | CLL /KEEP LINK CLEAAR | |
108 | SNA CLA | |
109 | KSF /WITH THE FLAG UP. | |
110 | JMP NOTCTC /IF NOT, CONTINUE | |
111 | SCDIF0, CDF CIF 0 /IF SO, RETURN TO OS/8 | |
112 | JMP I S7600 | |
113 | ||
114 | NOTCTC, SDN /WAIT FOR THE DONE FLAG TO COME UP | |
115 | JMP DONELP /BEFORE YOU LOAD THE COMMAND REGISTER | |
116 | TAD TRANS /NOW GET THE NEW COMMAND REGISTER CONTENTS | |
117 | LCD /AND LOAD IT. | |
118 | SER /SKIP IF I/O ERROR | |
119 | JMP I LDCMD /AND RETURN | |
120 | CLA CLL CML RAR /SET AC TO 4000 | |
121 | JMP SRET /TAKE ERROR RETURN | |
122 | ||
123 | ||
124 | RXA0, RXVER /ENTRY POINT FOR UNIT 0 | |
125 | CLA /BE PROTECTIVE | |
126 | JMP RXCOMN /GO TO COMMON CODE | |
127 | S70, 70 /** MUST BE AT 33 ON THIS PAGE** | |
128 | ||
129 | IFNZRO S70&177-33 <.ERROR> | |
130 | ||
131 | MQ, /DIVIDE TEMPORARY | |
132 | RXA1, RXVER /ENTRY POINT FOR UNIT 1 | |
133 | CLA /CAREFUL, CAREFUL! | |
134 | TAD RXA1 | |
135 | DCA RXA0 /PUT CALLING ADDR IN KNOWN PLACE | |
136 | TAD DIVLP /GET "20" | |
137 | RXCOMN, TAD DIVRAL /SET AC TO 20*UNIT+4 | |
138 | DCA UNIT /SAVE UNIT NUMBER | |
139 | RDF | |
140 | TAD SCDIF0 /REMEMBER CALLING FIELD FOR RETURN | |
141 | DCA SRET | |
142 | \f | |
143 | / OVERALL COMMENTS: | |
144 | / | |
145 | / LINK REMAINS 0 THROUGH THE MAIN PROCESSING LOOP | |
146 | / EXCEPT AS MANIPULATED BY DIVSUB | |
147 | / | |
148 | / OVERALL LOOP CONTROL THROUGH BC IS MILDLY ODD. | |
149 | / BC STARTS WITH MINUS COUNT OF THE # OF WORDS TO BE TRANSFERRED. | |
150 | / BC IS INCREMENTED 77 TIMES AT THE SILO CODE, AND 1 TIME AFTER | |
151 | / THE I/O OPERATION. | |
152 | / A READ OPERATION STARTS AND FINISHES AT THE MIDDLE OF THE LOOP. | |
153 | / A WRITE OEPRATION STARTS AT THE TOP, AND FINISHES AT BOTTOM. | |
154 | / THUS, A 1 BLOCK READ INCREMENTS 1, 77, 1, 77 AND EXITS FROM MIDDLE. | |
155 | / AND, A 1 BLOCK WRITE INCREMENTS 77, 1, 77, 1 AND EXITS FROM BOTTOM. | |
156 | / | |
157 | / DIVISION IS CARRIED OUT IN PARALLEL WITH I/O OPERATION BECAUSE OF | |
158 | / TIMING CONSIDERATIONS OF THE VT78. | |
159 | / | |
160 | / THERE IS NO ERROR RETRY, NOT PARTICULARLY CRITICAL FOR A FLOPPY. | |
161 | ||
162 | CLL CML CLA RAR /SET LINK=0, AC=4000 | |
163 | TAD I SYS /TO PUT READ-WRITE BIT TO LINK | |
164 | S33, AND S70 /KEEP BITS FOR CDF | |
165 | TAD SCDF0 /ADDING IN CDF LITERAL | |
166 | DCA BUFCDF /CDF INSTRUCTION TO USER'S BUFFER | |
167 | CML RTL /FUNCTION CODE, 0=WRITE, 2=READ | |
168 | DCA FN | |
169 | TAD I SYS /MAKE CONTROL COUNT | |
170 | RAL | |
171 | AND S7600 /MAKE CONTROL COUNT FOR TOTAL | |
172 | CIA /NUMBER OF WORDS | |
173 | DCA BC | |
174 | ISZ SYS | |
175 | TAD I SYS /FETCH BUFFER ADDRESS | |
176 | DCA BUF | |
177 | ISZ SYS | |
178 | TAD I SYS /OS8 BLOCK # | |
179 | CLL RTL /TIMES 4 TO BE FLOPPY SECTOR # | |
180 | DCA REC | |
181 | ISZ SYS /ERROR EXIT FROM I/O CALL | |
182 | JMS DIVSUB /COMPUTE TRACK/SECTOR FOR FIRST I/O | |
183 | TAD FN /READ OR WRITE START DIFFERENTLY | |
184 | SZA CLA /SKIP ON WRITE | |
185 | JMP STREAD /GO TO READ | |
186 | / | |
187 | / WRITE FALLS THRU....... | |
188 | / | |
189 | \f/ | |
190 | / | |
191 | / TOP OF MAIN PROCESSING LOOP | |
192 | / | |
193 | SETSLO, TAD FN /SET SILO TO LOAD-UNLOAD DEPENDING | |
194 | JMS LDCMD | |
195 | TAD S7700 /SILO CONTROL COUNT 100 OCTAL | |
196 | DCA FLPWC | |
197 | BUFCDF, HLT /CDF TO USER'S BUFFER PLACED HERE | |
198 | TRLOOP, TAD I BUF /FETCH A WORD IN CASE WRITE | |
199 | STR /WAIT | |
200 | JMP .-1 | |
201 | XDR /AC TO SILO; OR; SILO TO AC | |
202 | DCA I BUF /PLACE A WORD IN CASE READ; WRITE REPLACES SAME. | |
203 | ISZ BUF /MOVE TO NEXT BUFFER LOCATION (MAY SKIP) | |
204 | S77, 77 /LITERAL 77, EXECUTES AS A NOP | |
205 | ISZ FLPWC /DONE WITH 100 OCTAL SILO OPERATION | |
206 | JMP TRLOOP /NO | |
207 | TAD BC /INCREMENT BC BY 77 HERE, 1 LATER | |
208 | TAD S77 /CHECKING FOR A READ EXIT | |
209 | MAGIC, SNA /IF BC HAS GONE TO ZERO, NO-OP FOR LDCMD | |
210 | JMP OKEX /READ EXIT. | |
211 | DCA BC /REPLACING BC FOR WRITE EXIT CHECK AT LOOP END | |
212 | / | |
213 | / MIDDLE OF MAIN PROCESSING LOOP | |
214 | / | |
215 | STREAD, TAD FN /READ STARTS HERE | |
216 | TAD UNIT /SET UP DO DO READ OR WRITE I/O | |
217 | JMS LDCMD | |
218 | TAD MQ /LOAD PRECOMPUTED SECTOR INFO | |
219 | STR | |
220 | JMP .-1 /IN CASE NOT READY | |
221 | XDR | |
222 | S7700, 7700 /CLEAR AC, CAN'T SKIP (XDR LEAVES AC ALONE) | |
223 | TAD QUO /TRACK | |
224 | STR /ILLEGAL 7700 ENTRY WILL HANG; THE FUNCTION | |
225 | JMP .-1 /IS NOT SET UP (LDCMD) | |
226 | XDR | |
227 | S7600, 7600 | |
228 | ISZ REC /MOVE TO NEXT FLOPPY SECTOR | |
229 | JMS DIVSUB /COMPUTE NEXT TRACK AND SECTOR DURING THIS I/O | |
230 | TAD MAGIC /WAIT FOR I/O TO COMPLETE | |
231 | JMS LDCMD | |
232 | ISZ BC /CHECK FOR WRITE EXIT | |
233 | JMP SETSLO /NO, BACK TO TOP | |
234 | OKEX, ISZ SYS /BUMP TO REGULAR EXIT | |
235 | SRET, HLT /CDF CIF FOR USER'S CALLING FIELD | |
236 | JMP I SYS /GONE | |
237 | / | |
238 | UNIT, 0 /UNIT | |
239 | SYS=RXA0 | |
240 | / | |
241 | \f/ | |
242 | / | |
243 | / LITERALS | |
244 | / | |
245 | SM15, -15 | |
246 | SCDF0, CDF 0 | |
247 | / | |
248 | / DIVSUB | |
249 | / | |
250 | / MUST ENTER WITH LINK AND AC 0 | |
251 | / COMPUTES TRACK IN 'QUO', SECTOR IN 'MQ', FROM # IN 'REC' | |
252 | / | |
253 | / REPEATED SUBTRACTS OF 13 DECIMAL LEAVE THE HIGH N-1 BITS OF | |
254 | / QUOTIENT IN QUO, THE LOW BIT OF QUOTIENT IN LINK, AND THE | |
255 | / REMAINDER IN AC. THE INTERLEAVE IS ACCOMPLISHED BY SHIFTING | |
256 | / LOW QUOTINET BIT INTO LOW REMAINDER BIT. | |
257 | / | |
258 | DIVSUB, 0 | |
259 | DCA QUO /INIT QUOTIENT FOR DIVIDE | |
260 | TAD REC /RECORD # MASSAGED IN AC | |
261 | DIVLP, SNL /LINK USAGE REVERSED FROM RICHIE'S CODE | |
262 | ISZ QUO /ISZ EVERY OTHER TIME, <=DIVIDE BY 26 | |
263 | TAD SM15 /THE -13 DECIMAL | |
264 | SMA /SKIP ON DONE | |
265 | JMP DIVLP /MORE | |
266 | DIVRAL, RAL /LINK USAGE REVERSED; INTERLEAVE!! | |
267 | TAD S33 /ADD 233 (200 IRREL) MAKING SECTOR | |
268 | DCA MQ | |
269 | JMP I DIVSUB /LEAVING LINK AND AC 0 | |
270 | QUO, 0 /DIVIDE TEMP | |
271 | / | |
272 | ||
273 | $ | |
274 | ||
275 | \f |