1               / STAND-ALONE CASSETTE HANDLER
   2               
   3               /       DEC-8E-UCASA-A-LA
   4               
   5               /       COPYRIGHT 1972
   6               
   7               /       DIGITAL EQUIPMENT CORPORATION
   8               
   9               /       MAYNARD MASSACHUSETTS   01754
  10               
  11               
  12               /       OCTOBER 19, 1972
  13               
  14                       KCLR=6700       /CLEAR ALL
  15                                       /CLEAR STATUS A AND B REGISTERS.
  16                       KSDR=6701       /SKIP ON DATA FLAG
  17                       KSEN=6702       /SKIP ON ERROR
  18                       KSBF=6703       /SKIP ON READY FLAG
  19                       KLSA=6704       /LOAD STATUS A FROM AC 4-11
  20                                       /CLEAR AC, THEN
  21                                       /LOAD 8 BIT COMPLEMENT OF STATUS A
  22                                       /BACK INTO AC
  23                       KSAF=6705       /SKIP ON ANY FLAG OR ERROR
  24                       KGOA=6706       /ASSERT THE CONTENTS OF STATUS A,
  25                                       /TRANSFER DATA IF READ OR WRITE
  26                       KRSB=6707       /READ STATUS B INTO AC 4-11
  27               
  28               
  29                       ORG2=1400
  30                       ORG3=1600
  31                       ORG1=1200       /ORIGIN FOR SUBROUTINE
  32                       AFIELD=1        /FIELD OF SUBROUTINE
  33                       F=10^AFIELD
  34               
  35                       INT=1
  36                       DISMIS=6
  37               /THIS ROUTINE LEAVES WITH INTERRUPTS OFF AND DEVICE SELECTED
  38               /AND READY.
  39               /THE NEW UNIT NUMBER (0-7) IS IN THE AC.
  40               /THE UNIT  NUMBER IS IN BITS 8-11 OF THE AC.
  41               /RETURN 1 IS MADE IF THE UNIT IS NOT READY.
  42               /CINUSE IS SET TO 1.
  43               /THE HANDLER MUST NOT ALREADY BE IN USE.
  44               /THE DATA FIELD IS INTERROGATED
  45               /AND A RETURN CIF CDF IS BUILT
  46               /AND STORED IN LOCATION RETCIF
  47               
  48                       FIELD AFIELD
  49               
  50                       *ORG1
  51               
  52                       IFNZRO INT <
  53               
  54 011200  0000  WAIT,   0
  55 011201  6214          RDF
  56 011202  1377          TAD (CIF CDF
  57 011203  3216          DCA WAITEND
  58 011204  6211          CDF F
  59 011205  1776  CWAIT,  TAD I (CINUSE
  60 011206  7450          SNA
  61 011207  5215          JMP WLV         /ZERO MEANS READY
  62 011210  7700          SMA CLA
  63 011211  5205          JMP CWAIT       /1 MEANS IN USE
  64 011212  3776          DCA I (CINUSE   /-1 MEANS HAD ERROR
  65 011213  1775          TAD I (BSTATE   /LEAVE WITH STATUS REGISTER B IN AC
  66 011214  7410          SKP             /TAKE ERROR RETURN
  67 011215  2200  WLV,    ISZ WAIT
  68 011216  7402  WAITEND,HLT
  69 011217  5600          JMP I WAIT
  70                       >
  71 011220  0000  FIXDVC,        0
  72 011221  3264          DCA DVC
  73 011222  6214          RDF
  74 011223  1377          TAD (CIF CDF
  75 011224  6211          CDF F
  76 011225  3263          DCA TMP
  77 011226  1620          TAD I FIXDVC
  78 011227  3332          DCA ERRET
  79 011230  2220          ISZ FIXDVC
  80 011231  1263          TAD TMP
  81 011232  3732          DCA I ERRET
  82 011233  6002          IFNZRO INT <IOF>
  83 011234  1264          TAD DVC
  84 011235  7010          RAR             /MOVE UNIT TO LINK; DEVICE TO AC
  85 011236  0374          AND (3          /MASK OFF DEVICE CODE
  86 011237  3264          DCA DVC         /SAVE DEVICE CODE
  87 011240  7430          SZL
  88 011241  1373          TAD (100
  89 011242  3331          DCA ABUNIT      /SET UNIT IN BIT 5
  90 011243  1264          TAD DVC
  91 011244  7106          CLL RTL
  92 011245  7004          RAL             /UGLY
  93 011246  3264          DCA DVC         /MOVE TO BITS 6-8
  94 011247  1372          TAD (IOTBL
  95 011250  3265          DCA IOTPTR
  96 011251  1665  IOTLOOP,TAD I IOTPTR
  97 011252  7450          SNA             /END OF TABLE?
  98 011253  5266          JMP CHECKR      /YES
  99 011254  3263          DCA TMP
 100 011255  1663          TAD I TMP
 101 011256  0371          AND (7707       /MASK OUT OLD DVC
 102 011257  1264          TAD DVC         /INSERT NEW ONE
 103 011260  3663          DCA I TMP       /REPLACE
 104 011261  2265          ISZ IOTPTR      /POINT TO NEXT ONE
 105 011262  5251          JMP IOTLOOP
 106               
 107 011263  0000  TMP,    0
 108 011264  0000  DVC,    0               /DEVICE CODE
 109 011265  0000  IOTPTR, 0
 110 011266  4770  CHECKR,        JMS I (CLEAR
 111 011267  1367          TAD (200
 112 011270  4766          JMS I (LOADA    /SELECT DRIVE
 113 011271  4765          JMS I (CHECKB
 114 011272  0364          AND (7735       /IGNORE EOT/BOT FLAG
 115                                       /AND WLO
 116 011273  1363          TAD (-1
 117 011274  7640          SZA CLA
 118 011275  5732          JMP I ERRET     /NOT READY
 119 011276  2776          ISZ I (CINUSE
 120 011277  5620          JMP I FIXDVC
 121               
 122 011300  6700  ERRCOV, KCLR
 123 011301  1362          TAD     (250+INT
 124 011302  4766          JMS I   (LOADA
 125 011303  4761          JMS I   (GO     /BACKSPACE BLOCK
 126 011304  4760          JMS I   (CRET   /WAIT
 127 011305  4765          JMS I   (CHECKB
 128 011306  0357          AND     (374    /KILL WRITE-LOCK BIT
 129 011307  7640          SZA CLA
 130 011310  5756          JMP I   (ERRR
 131 011311  4755          JMS I   (SETUP  /RE-SET UP OPERATION
 132 011312  5754          JMP I   (CRET+1 /GO AWAY
 133               
 134 011313  1454  IOTBL,  IOT0
 135 011314  1465          IOT1
 136 011315  1326          IOT4
 137 011316  1503          IOT5
 138 011317  1457          IOT6
 139 011320  1671          IOT6C
 140 011321  1446          IOT7
 141 011322  1300          ERRCOV
 142 011323  0000          0
 143 011324  0000  LOADA, 0
 144 011325  1331          TAD ABUNIT
 145 011326  6704  IOT4,   KLSA
 146 011327  7200          CLA
 147 011330  5724          JMP I LOADA
 148               
 149 011331  0000  ABUNIT, 0
 150 011332  0000  ERRET,  0               /ERROR RETURN LOCATION
 151 011354  1500          PAGE
     011355  1637  
     011356  1723  
     011357  0374  
     011360  1477  
     011361  1456  
     011362  0251  
     011363  7777  
     011364  7735  
     011365  1445  
     011366  1324  
     011367  0200  
     011370  1452  
     011371  7707  
     011372  1313  
     011373  0100  
     011374  0003  
     011375  1476  
     011376  1475  
     011377  6203  
 152                      *ORG2
 153               
 154 011400  0000  UTIL,   0
 155 011401  3242          DCA TEMPU
 156 011402  3244          DCA REWSW       /ZERO REWIND SWITCH
 157 011403  1600          TAD I UTIL
 158 011404  1377          TAD (-10
 159 011405  7450          SNA
 160 011406  2244          ISZ REWSW
 161 011407  2200          ISZ UTIL
 162 011410  1376          TAD (210+INT
 163 011411  3243          DCA TEMPFN
 164 011412  1242          TAD TEMPU
 165 011413  4775          JMS I (FIXDVC   /FIX DEVICE CODE
 166 011414  1423          UTEND           /UNIT NOT READY
 167 011415  1374          TAD (UT
 168 011416  3277          DCA CRET        /SET RETURN ADDRESS
 169 011417  1243          TAD TEMPFN
 170 011420  4773          JMS I (LOADA
 171 011421  4256          JMS GO          /INITIATE UTIL
 172                       IFZERO INT <JMP CRET+1>
 173 011422  2200          ISZ UTIL
 174 011423  7402  UTEND,  HLT
 175 011424  6001          IFNZRO INT <ION>
 176 011425  5600          JMP I UTIL
 177 011426  4245  UT,     JMS CHECKB      /LOOK AT STATUS B
 178 011427  0372          AND (50         /CHECK FOR CL, EMPTY, OR WLO
 179                                       /GIVE NO ERROR ON WLO ************
 180                                       /BAD FOR WRGAP
 181 011430  7450          SNA
 182 011431  5240          JMP OK          /NO ERRORS
 183 011432  1371          TAD (-40
 184 011433  7640          SZA CLA
 185 011434  5237          JMP NOTOK       /ERROR NOT CL
 186 011435  1244          TAD REWSW
 187 011436  7650          SNA CLA         /CL OK IF DID REWIND
 188 011437  7240  NOTOK,  STA
 189 011440  4252  OK,     JMS CLEAR
 190 011441  5300          IFNZRO INT <JMP CRET+1>
 191                       IFZERO INT <
 192                       TAD CINUSE
 193                       SMA CLA
 194                       JMP UTEND-1
 195                       TAD BSTATE      /ERROR
 196                       JMP UTEND
 197                       >
 198               
 199 011442  0000  TEMPU,  0
 200 011443  0000  TEMPFN, 0
 201 011444  0000  REWSW,  0               /1 MEANS OPERATION IS REWIND
 202 011445  0000  CHECKB,        0
 203 011446  6707  IOT7,   KRSB            /READ STATUS B INTO AC 4-11
 204 011447  3276          DCA BSTATE      /SAVE STATUS B
 205 011450  1276          TAD BSTATE
 206 011451  5645          JMP I CHECKB
 207               
 208 011452  0000  CLEAR,  0
 209 011453  3275          DCA CINUSE      /LEAVE STATUS CONDITION IN AC; -1 MEANS  ERROR
 210 011454  6700  IOT0,   KCLR            /CLEAR STATUS A AND B
 211 011455  5652          JMP I CLEAR
 212               
 213 011456  0000  GO,     0
 214 011457  6706  IOT6,   KGOA            /ASSERT CONTENTS OF STATUS A
 215 011460  7200          CLA
 216 011461  5656          JMP I GO
 217               
 218 011462  0000  CHK,    0
 219 011463  4770          JMS I (CHECKB
 220 011464  0367          AND (376
 221 011465  6701  IOT1,   KSDR
 222 011466  7410          SKP             /DATA FLAG NOT UP -
 223 011467  5662          JMP I CHK
 224 011470  1366          TAD (-20
 225 011471  7650          SNA CLA         /IS IT END OF FILE?
 226 011472  5765          JMP I (ERRR     /YES, ERROR - BUT DON'T RETRY
 227 011473  1276          TAD BSTATE
 228 011474  5662          JMP I CHK
 229               
 230 011475  0000  CINUSE, 0               /1 MEANS HANDLER IN USE
 231 011476  0000  BSTATE, 0               /STATUS OF REGISTER B ON ERROR
 232                      IFNZRO INT <
 233               
 234 011477  0000  CRET,   0
 235 011500  6203          CIF CDF 0
 236 011501  5702          JMP I .+1
 237 011502  0006          DISMIS
 238               
 239 011503  6705  IOT5,   KSAF
 240 011504  7402  NXTSKP, HLT
 241 011505  5677          JMP I CRET
 242                       >
 243               
 244                       IFZERO INT <
 245               
 246               CRET,   0
 247                       CDF F
 248               IOT5,   KSAF
 249                       JMP .-1
 250                       JMP I CRET
 251                       >
 252 011565  1723          PAGE
     011566  7760  
     011567  0376  
     011570  1445  
     011571  7740  
     011572  0050  
     011573  1324  
     011574  1426  
     011575  1220  
     011576  0211  
     011577  7770  
 253                      *ORG3
 254               
 255 011600  0000  HANDLER,0
 256 011601  3234          DCA TUN
 257 011602  1600          TAD I HANDLER   /GET FUNCTION CONTROL WORD
 258 011603  0337          AND L70         /ISOLATE FIELD OF BUFFER
 259 011604  1377          TAD (CDF
 260 011605  3256          DCA WCDF
 261 011606  1600          TAD I HANDLER   /RETRIEVE FUNCTION CONTROL WORD
 262 011607  7004          RAL             /READ/WRITE BIT TO LINK
 263 011610  7204          CLA RAL
 264 011611  3235          DCA RW          /RW=1 IF WRITE
 265 011612  2200          ISZ HANDLER     /POINT TO BUFFER ADDRESS
 266 011613  1600          TAD I HANDLER   /GET BUFFER ADDRESS
 267 011614  3351          DCA BUFFER      /SAVE IT
 268 011615  2200          ISZ HANDLER     /POINT TO ERROR RETURN
 269 011616  1234          TAD TUN
 270 011617  4776          JMS I (FIXDVC
 271 011620  1631          LV              /NOT READY
 272 011621  1256          TAD WCDF
 273 011622  3335          DCA BFIELD
 274 011623  1256          TAD WCDF
 275 011624  3277          DCA BFLD
 276 011625  7346          STA CLL RTL     /TAD (-3
 277 011626  3236          DCA ERKNT
 278 011627  4237          JMS     SETUP   /SET UP READ OR WRITE
 279                       IFZERO INT <JMP I (CRET+1>
 280 011630  2200          ISZ HANDLER     /POINT TO GOOD RETURN
 281 011631  7402  LV,     HLT
 282 011632  6001          IFNZRO INT <ION>
 283 011633  5600          JMP I HANDLER
 284 011634  0000  TUN,    0               /TEMP
 285 011635  0000  RW,     0               /1 IF WRITE
 286 011636  7775  ERKNT,  -3
 287 011637  0000  SETUP, 0
 288 011640  1235          TAD RW
 289 011641  1375          TAD (WRITEX
 290 011642  3774          DCA I (CRET     /SET RETURN ADDRESS
 291 011643  1351          TAD BUFFER
 292 011644  3347          DCA BPTR
 293 011645  1773          TAD I (BSIZE
 294 011646  7040          CMA             /WANT TO READ ONE MORE
 295 011647  1235          TAD RW
 296 011650  3346          DCA BKNT
 297 011651  1235          TAD RW
 298 011652  7106          CLL RTL
 299 011653  7006          RTL             /WRITE FN CODE=20
 300 011654  1372          TAD (200+INT    /SELECT AND INTERRUPT ENABLE
 301 011655  4771          JMS I (LOADA
 302 011656  7402  WCDF,   HLT
 303 011657  1235          TAD RW
 304 011660  7640          SZA CLA
 305 011661  1747          TAD I BPTR
 306 011662  6211          CDF F
 307 011663  4770          JMS I (GO
 308 011664  5637          JMP I   SETUP
 309               
 310 011665  4767  READX, JMS I (CHK
 311 011666  0302          AND L374
 312 011667  7440          SZA
 313 011670  5317          JMP ERRX
 314 011671  6706  IOT6C,  KGOA            /GET CHAR JUST READ
 315 011672  3350          DCA BYTE
 316 011673  2346          ISZ BKNT
 317 011674  7410          SKP
 318 011675  5305          JMP RWCRC
 319 011676  1350  BMODE,  TAD BYTE
 320 011677  7402  BFLD,   HLT
 321 011700  3747          DCA I BPTR
 322 011701  2347          ISZ BPTR
 323 011702  0374  L374,   374
 324 011703  5766          JMP I (CRET+1   /CRET ALREADY SET UP
 325               
 326 011704  0200  BSIZE,  200
 327 011705  1365  RWCRC, TAD (260+INT    /ENABLE, ENABLE INTER, READ CRC
 328 011706  4771          JMS I (LOADA
 329 011707  4770          JMS I (GO
 330 011710  4774          JMS I (CRET
 331 011711  4767          JMS I (CHK
 332 011712  4770  CRCMN,  JMS I (GO
 333 011713  4774          JMS I (CRET
 334 011714  4764          JMS I (CHECKB
 335 011715  0363          AND (7775       /IGNORE WLO
 336 011716  1362          TAD (-1
 337 011717  7650  ERRX,   SNA CLA         /ERRORS?
 338 011720  5324          JMP     ERRR+1  /NO - CLEAN BILL OF HEALTH
 339 011721  2236          ISZ     ERKNT   /TRY 3 TIMES
 340 011722  5761          JMP I   (ERRCOV /RETRY
 341 011723  7240  ERRR,   STA             /ERROR WHILE READING CRC
 342 011724  4760          JMS I (CLEAR
 343 011725  5766          IFNZRO INT <JMP I (CRET+1>
 344                       IFZERO INT <
 345                       TAD I (CINUSE
 346                       SMA CLA
 347                       JMP LV-1
 348                       TAD I (BSTATE
 349                       JMP LV
 350                       >
 351 011726  5265  WRITEX,        JMP READX
 352 011727  4767          JMS I (CHK
 353 011730  7440          SZA
 354 011731  5317          JMP ERRX
 355 011732  2346          ISZ BKNT
 356 011733  7410          SKP
 357 011734  5343          JMP WCRC
 358 011735  7402  BFIELD, HLT
 359 011736  2347          ISZ BPTR
 360 011737  0070  L70,    70
 361 011740  1747          TAD I BPTR
 362 011741  4770          JMS I (GO
 363 011742  5766          JMP I (CRET+1
 364               
 365               
 366 011743  1365  WCRC,   TAD (260+INT
 367 011744  4771          JMS I (LOADA
 368 011745  5312          JMP CRCMN
 369 011746  0000  BKNT,   0               /NUMBER OF CHARS EXPECTED
 370 011747  0000  BPTR,   0               /NEXT LOCATION IN BUFFER TO STORE INTO
 371 011750  0000  BYTE,   0               /TEMPORARILY HOLDS BYTE FOUND
 372 011751  0000  BUFFER, 0
 373 011760  1452          PAGE
     011761  1300  
     011762  7777  
     011763  7775  
     011764  1445  
     011765  0261  
     011766  1500  
     011767  1462  
     011770  1456  
     011771  1324  
     011772  0201  
     011773  1704  
     011774  1477  
     011775  1726  
     011776  1220  
     011777  6201  
 374                      $