v4.0/src/DOS/MS_CODE.ASM

   1 ;       SCCSID = @(#)mscode.asm 1.2 85/07/23
   2 ;
   3 ; MSCODE.ASM -- MSDOS code
   4 ;
   5
   6 .xlist
   7 .xcref
   8 include dossym.inc
   9 include devsym.inc
  10 include dosseg.asm
  11 include ifssym.inc
  12 include fastopen.inc
  13 include fastxxxx.inc
  14 .cref
  15 .list
  16
  17 AsmVars <Kanji, Debug>
  18
  19 CODE    SEGMENT BYTE PUBLIC 'CODE'
  20
  21 ASSUME  CS:DOSGROUP,DS:NOTHING,ES:NOTHING,SS:NOTHING
  22
  23     I_need  InDos,BYTE                  ; TRUE => we are in dos, no interrupt
  24     I_need  OpenBuf,128                 ; temp name buffer
  25     I_need  ExtErr,WORD                 ; extended error code
  26     I_need  User_SS,WORD                ; stack segment from user
  27     I_need  User_SP,WORD                ; stack pointer from user
  28     I_need  DskStack,BYTE               ; stack segment inside DOS
  29     I_need  ThisCDS,DWORD               ; Currently referenced CDS pointer
  30     I_need  ThisDPB,DWORD               ; Currently referenced DPB pointer
  31     I_need  Err_Table_21                ; allowed return map table for errors
  32     I_need  FailErr,BYTE                ; TRUE => system call is being failed
  33     I_need  ExtErr_Action,BYTE          ; recommended action
  34     I_need  ExtErr_Class,BYTE           ; error classification
  35     I_need  ExtErr_Locus,BYTE           ; error location
  36     I_need  I21_Map_E_Tab,BYTE          ; mapping extended error table
  37     I_need  User_In_AX,WORD             ; initial input user AX
  38     I_need  FOO,WORD                    ; return address for dos 2f dispatch
  39     I_need  DTAB,WORD                   ; dos 2f dispatch table
  40     I_need  HIGH_SECTOR,WORD            ; >32mb
  41     I_need  IFS_DRIVER_ERR,WORD         ; >32mb
  42     I_need  FastOpenFlg,BYTE            ;
  43     I_need  FastSeekFlg,BYTE            ;
  44     I_need  CURSC_DRIVE,BYTE            ;
  45
  46 BREAK <NullDev -- Driver for null device>
  47
  48 procedure   SNULDEV,FAR
  49 ASSUME DS:NOTHING,ES:NOTHING,SS:NOTHING
  50         OR      ES:[BX.REQSTAT],STDON   ; Set done bit
  51 entry INULDEV
  52         RET                             ; MUST NOT BE A RETURN!
  53 EndProc SNULDEV
  54
  55 BREAK <AbsDRD, AbsDWRT -- INT int_disk_read, int_disk_write handlers>
  56
  57
  58 TABLE   SEGMENT
  59 Public MSC001S,MSC001E
  60 MSC001S label byte
  61         IF      IBM
  62 ; Codes returned by BIOS
  63 ERRIN:
  64         DB      2                       ; NO RESPONSE
  65         DB      6                       ; SEEK FAILURE
  66         DB      12                      ; GENERAL ERROR
  67         DB      4                       ; BAD CRC
  68         DB      8                       ; SECTOR NOT FOUND
  69         DB      0                       ; WRITE ATTEMPT ON WRITE-PROTECT DISK
  70 ERROUT:
  71 ; DISK ERRORS RETURNED FROM INT 25 and 26
  72         DB      80H                     ; NO RESPONSE
  73         DB      40H                     ; Seek failure
  74         DB      2                       ; Address Mark not found
  75         DB      10H                     ; BAD CRC
  76         DB      4                       ; SECTOR NOT FOUND
  77         DB      3                       ; WRITE ATTEMPT TO WRITE-PROTECT DISK
  78
  79 NUMERR  EQU     $-ERROUT
  80         ENDIF
  81 MSC001E label byte
  82
  83 TABLE   ENDS
  84
  85 ;   AbsSetup - setup for abs disk functions
  86
  87 Procedure   AbsSetup,NEAR
  88         ASSUME  CS:DOSGroup,DS:NOTHING,ES:NOTHING,SS:DOSGroup
  89         INC     INDOS
  90         STI
  91         CLD
  92         PUSH    DS
  93         Context DS
  94         CALL    GETBP
  95         JC      errdriv                 ;PM. error drive                        ;AN000;
  96         MOV     ES:[BP.dpb_free_cnt],-1 ; do not trust user at all.
  97 errdriv:
  98         POP     DS
  99 ASSUME  DS:NOTHING
 100         retc
 101
 102         MOV     [HIGH_SECTOR],0         ;>32mb  from API                        ;AN000;
 103         CALL    RW32_CONVERT            ;>32mb convert 32bit format to 16bit    ;AN000;
 104         retc
 105
 106         invoke  SET_RQ_SC_PARMS         ;LB. set up SC parms                    ;AN000;
 107         PUSH    DS
 108         PUSH    SI
 109         PUSH    AX
 110         Context DS
 111         MOV     SI,OFFSET DOSGROUP:OPENBUF
 112         MOV     [SI],AL
 113         ADD     BYTE PTR [SI],"A"
 114         MOV     WORD PTR [SI+1],003AH   ; ":",0
 115         MOV     AX,0300H
 116         CLC
 117         INT     int_IBM                 ; Will set carry if shared
 118         POP     AX
 119         POP     SI
 120         POP     DS
 121 ASSUME  DS:NOTHING
 122         retnc
 123         MOV     ExtErr,error_not_supported
 124         return
 125 EndProc AbsSetup
 126
 127 ; Interrupt 25 handler.  Performs absolute disk read.
 128 ; Inputs:       AL - 0-based drive number
 129 ;               DS:BX point to destination buffer
 130 ;               CX number of logical sectors to read
 131 ;               DX starting  logical sector number (0-based)
 132 ; Outputs:      Original flags still on stack
 133 ;               Carry set
 134 ;                   AH error from BIOS
 135 ;                   AL same as low byte of DI from INT 24
 136
 137         procedure   ABSDRD,FAR
 138         ASSUME  CS:DOSGroup,DS:NOTHING,ES:NOTHING,SS:NOTHING
 139
 140         CLI
 141         MOV     [user_SS],SS
 142         MOV     [user_SP],SP
 143         PUSH    CS
 144         POP     SS
 145 ASSUME  SS:DOSGROUP
 146         MOV     SP,OFFSET DOSGROUP:DSKSTACK
 147         invoke  Save_World                    ;>32mb save all regs              ;AN000;
 148         PUSH    ES
 149         CALL    AbsSetup
 150         JC      ILEAVE
 151 if not ibmcopyright
 152 ; Here is a gross temporary fix to get around a serious design flaw in
 153 ;  the secondary cache.  The secondary cache does not check for media
 154 ;  changed (it should).  Hence, you can change disks, do an absolute
 155 ;  read, and get data from the previous disk.  To get around this,
 156 ;  we just won't use the secondary cache for absolute disk reads.
 157 ;                                                      -mw 8/5/88
 158         EnterCrit   critDisk
 159         MOV     [CURSC_DRIVE],-1              ; invalidate SC                   ;AN000;
 160         LeaveCrit   critDisk
 161 endif
 162         invoke  DSKREAD
 163 TLEAVE:
 164         JZ      ILEAVE
 165
 166         IF      IBM
 167 ; Translate the error code to ancient 1.1 codes
 168         PUSH    ES
 169         PUSH    CS
 170         POP     ES
 171         XOR     AH,AH                   ; Nul error code
 172         MOV     CX,NUMERR               ; Number of possible error conditions
 173         MOV     DI,OFFSET DOSGROUP:ERRIN    ; Point to error conditions
 174         REPNE   SCASB
 175         JNZ     LEAVECODE               ; Not found
 176         MOV     AH,ES:[DI+NUMERR-1]     ; Get translation
 177 LEAVECODE:
 178         POP     ES
 179         ENDIF
 180         MOV     [IFS_DRIVER_ERR],AX     ;>32mb save error
 181         STC
 182 ILEAVE:
 183         POP     ES
 184         invoke  Restore_World                ;>32mb                             ;AN000;
 185         CLI
 186         DEC     INDOS
 187         MOV     SS,[user_SS]
 188 ASSUME  SS:NOTHING
 189         MOV     SP,[user_SP]
 190         MOV     AX,[IFS_DRIVER_ERR]          ;>32mb restore error               ;AN000;
 191         STI
 192         RET                             ; This must not be a RETURN!
 193 EndProc ABSDRD
 194
 195 ; Interrupt 26 handler.  Performs absolute disk write.
 196 ; Inputs:       AL - 0-based drive number
 197 ;               DS:BX point to source buffer
 198 ;               CX number of logical sectors to write
 199 ;               DX starting  logical sector number (0-based)
 200 ; Outputs:      Original flags still on stack
 201 ;               Carry set
 202 ;                   AH error from BIOS
 203 ;                   AL same as low byte of DI from INT 24
 204
 205         procedure   ABSDWRT,FAR
 206 ASSUME  DS:NOTHING,ES:NOTHING,SS:NOTHING
 207
 208         CLI
 209         MOV     [user_SS],SS
 210         MOV     [user_SP],SP
 211         PUSH    CS
 212         POP     SS
 213 ASSUME  SS:DOSGROUP
 214         MOV     SP,OFFSET DOSGROUP:DSKSTACK
 215         invoke  Save_World                    ;>32mb save all regs              ;AN000;
 216
 217         PUSH    ES
 218         CALL    AbsSetup
 219         JC      ILEAVE
 220
 221         EnterCrit   critDisk
 222         MOV     [CURSC_DRIVE],-1              ; invalidate SC                   ;AN000;
 223         CALL    Fastxxx_Purge                 ; purge fatopen                   ;AN000;
 224         LeaveCrit   critDisk
 225
 226         invoke  DSKWRITE
 227         JMP     TLEAVE
 228 EndProc ABSDWRT
 229
 230 ; Inputs:
 231 ;       AL = Logical unit number (A = 0)
 232 ; Function:
 233 ;       Find Drive Parameter Block
 234 ; Outputs:
 235 ;       ES:BP points to DPB
 236 ;       [THISDPB] = ES:BP
 237 ;       Carry set if unit number bad or unit is a NET device.
 238 ;               Later case sets extended error error_I24_not_supported
 239 ; No other registers altered
 240
 241 Procedure GETBP,NEAR
 242         DOSAssume   CS,<DS>,"GetBP"
 243         ASSUME  ES:NOTHING
 244
 245         PUSH    AX
 246         ADD     AL,1                    ; No increment; need carry flag
 247         JC      SkipGet
 248         invoke  GetThisDrv
 249         JNC     SkipGet                    ;PM. good drive                      ;AN000;
 250         XOR     AH,AH                      ;DCR. ax= error code                 ;AN000;
 251         CMP     AX,error_not_dos_disk      ;DCR. is unknown media ?             ;AN000;
 252         JZ      SkipGet                    ;DCR. yes, let it go                 ;AN000;
 253         STC                                ;DCR.                                ;AN000;
 254         MOV     ExtErr,AX                  ;PM. invalid drive or Non DOS drive  ;AN000;
 255         MOV     [IFS_DRIVER_ERR],0201H     ;PM. other errors/unknown unit       ;AN000;
 256 SkipGet:
 257         POP     AX
 258         retc
 259         LES     BP,[THISCDS]
 260         TEST    ES:[BP.curdir_flags],curdir_isnet   ; Clears carry
 261         JZ      GETBP_CDS
 262         LES     BP,ES:[BP.curdir_ifs_hdr]           ;IFS. if remote file        ;AN000;
 263         TEST    ES:[BP.ifs_attribute],IFSREMOTE     ;IFS.                       ;AN000;
 264         LES     BP,[THISCDS]
 265         JZ      GETBP_CDS                           ;IFS. then error            ;AN000;
 266         MOV     ExtErr,error_not_supported
 267         STC
 268         return
 269
 270 GETBP_CDS:
 271         LES     BP,ES:[BP.curdir_devptr]
 272
 273         entry   GOTDPB
 274         DOSAssume   CS,<DS>,"GotDPB"
 275 ; Load THISDPB from ES:BP
 276
 277         MOV     WORD PTR [THISDPB],BP
 278         MOV     WORD PTR [THISDPB+2],ES
 279         return
 280 EndProc GetBP
 281
 282 BREAK <SYS_RET_OK SYS_RET_ERR CAL_LK ETAB_LK set system call returns>
 283
 284 ASSUME  SS:DOSGROUP
 285
 286 ;
 287 ; These are the general system call exit mechanisms.  All internal system
 288 ; calls will transfer (jump) to one of these at the end.  Their sole purpose
 289 ; is to set the user's flags and set his AX register for return.
 290 ;
 291
 292 procedure   SYS_RETURN,NEAR
 293         ASSUME  DS:NOTHING,ES:NOTHING
 294 entry   SYS_RET_OK
 295         invoke  FETCHI_CHECK            ; TAG checking for FETCHI
 296         invoke  get_user_stack
 297         AND     [SI.user_F],NOT f_Carry ; turn off user's carry flag
 298         JMP     SHORT DO_RET            ; carry is now clear
 299
 300 entry   SYS_RET_ERR
 301         XOR     AH,AH                   ; hack to allow for smaller error rets
 302         invoke  ETAB_LK                 ; Make sure code is OK, EXTERR gets set
 303         CALL    ErrorMap
 304 entry   From_GetSet
 305         invoke  get_user_stack
 306         OR      [SI.user_F],f_Carry     ; signal carry to user
 307         STC                             ; also, signal internal error
 308 DO_RET:
 309         MOV     [SI.user_AX],AX         ; Really only sets AH
 310         return
 311
 312         entry   FCB_RET_OK
 313         entry   CPMFunc
 314         XOR     AL,AL
 315         return
 316
 317         entry   FCB_RET_ERR
 318         XOR     AH,AH
 319         mov     exterr,AX
 320         CALL    ErrorMap
 321         MOV     AL,-1
 322         return
 323
 324         entry   errorMap
 325         PUSH    SI
 326         MOV     SI,OFFSET DOSGROUP:ERR_TABLE_21
 327         CMP     [FAILERR],0             ; Check for SPECIAL case.
 328         JZ      EXTENDED_NORMAL         ; All is OK.
 329         MOV     [EXTERR],error_FAIL_I24 ; Ooops, this is the REAL reason
 330         MOV     SI,OFFSET DOSGROUP:ERR_TABLE_21
 331 EXTENDED_NORMAL:
 332         invoke  CAL_LK                  ; Set CLASS,ACTION,LOCUS for EXTERR
 333         POP     SI
 334         return
 335
 336 EndProc SYS_RETURN
 337
 338 ; Inputs:
 339 ;       SI is OFFSET in DOSGROUP of CLASS,ACTION,LOCUS Table to use
 340 ;               (DS NEED not be DOSGROUP)
 341 ;       [EXTERR] is set with error
 342 ; Function:
 343 ;       Look up and set CLASS ACTION and LOCUS values for GetExtendedError
 344 ; Outputs:
 345 ;       [EXTERR_CLASS] set
 346 ;       [EXTERR_ACTION] set
 347 ;       [EXTERR_LOCUS] set  (EXCEPT on certain errors as determined by table)
 348 ; Destroys SI, FLAGS
 349
 350         procedure   CAL_LK,NEAR
 351 ASSUME  DS:NOTHING,ES:NOTHING
 352
 353         PUSH    DS
 354         PUSH    AX
 355         PUSH    BX
 356         Context DS              ; DS:SI -> Table
 357         MOV     BX,[EXTERR]     ; Get error in BL
 358 TABLK1:
 359         LODSB
 360         CMP     AL,0FFH
 361         JZ      GOT_VALS        ; End of table
 362         CMP     AL,BL
 363         JZ      GOT_VALS        ; Got entry
 364         ADD     SI,3            ; Next table entry
 365         JMP     TABLK1
 366
 367 GOT_VALS:
 368         LODSW                   ; AL is CLASS, AH is ACTION
 369         CMP     AH,0FFH
 370         JZ      NO_SET_ACT
 371         MOV     [EXTERR_ACTION],AH     ; Set ACTION
 372 NO_SET_ACT:
 373         CMP     AL,0FFH
 374         JZ      NO_SET_CLS
 375         MOV     [EXTERR_CLASS],AL      ; Set CLASS
 376 NO_SET_CLS:
 377         LODSB                   ; Get LOCUS
 378         CMP     AL,0FFH
 379         JZ      NO_SET_LOC
 380         MOV     [EXTERR_LOCUS],AL
 381 NO_SET_LOC:
 382         POP     BX
 383         POP     AX
 384         POP     DS
 385         return
 386 EndProc CAL_LK
 387
 388 ; Inputs:
 389 ;       AX is error code
 390 ;       [USER_IN_AX] has AH value of system call involved
 391 ; Function:
 392 ;       Make sure error code is appropriate to this call.
 393 ; Outputs:
 394 ;       AX MAY be mapped error code
 395 ;       [EXTERR] = Input AX
 396 ; Destroys ONLY AX and FLAGS
 397
 398         procedure   ETAB_LK,NEAR
 399 ASSUME  DS:NOTHING,ES:NOTHING
 400
 401         PUSH    DS
 402         PUSH    SI
 403         PUSH    CX
 404         PUSH    BX
 405         Context DS
 406         MOV     [EXTERR],AX             ; Set EXTERR with "real" error
 407         MOV     SI,OFFSET DOSGROUP:I21_MAP_E_TAB
 408         MOV     BH,AL                   ; Real code to BH
 409         MOV     BL,BYTE PTR [USER_IN_AX + 1]    ; Sys call to BL
 410 TABLK2:
 411         LODSW
 412         CMP     AL,0FFH                 ; End of table?
 413         JZ      NOT_IN_TABLE            ; Yes
 414         CMP     AL,BL                   ; Found call?
 415         JZ      GOT_CALL                ; Yes
 416         XCHG    AH,AL                   ; Count to AL
 417         XOR     AH,AH                   ; Make word for add
 418         ADD     SI,AX                   ; Next table entry
 419         JMP     TABLK2
 420
 421 NOT_IN_TABLE:
 422         MOV     AL,BH                   ; Restore original code
 423         JMP     SHORT NO_MAP
 424
 425 GOT_CALL:
 426         MOV     CL,AH
 427         XOR     CH,CH                   ; Count of valid err codes to CX
 428 CHECK_CODE:
 429         LODSB
 430         CMP     AL,BH                   ; Code OK?
 431         JZ      NO_MAP                  ; Yes
 432         LOOP    CHECK_CODE
 433 NO_MAP:
 434         XOR     AH,AH                   ; AX is now valid code
 435         POP     BX
 436         POP     CX
 437         POP     SI
 438         POP     DS
 439         return
 440
 441 EndProc ETAB_LK
 442
 443 BREAK <DOS 2F Handler and default NET 2F handler>
 444
 445 IF installed
 446
 447 ;
 448 ; SetBad sets up info for bad functions
 449 ;
 450 Procedure   SetBad,NEAR
 451         ASSUME  CS:DOSGROUP,DS:NOTHING,ES:NOTHING,SS:NOTHING
 452         MOV     AX,error_invalid_function       ; ALL NET REQUESTS get inv func
 453         MOV     ExtErr_LOCUS,errLoc_UNK
 454         STC
 455         ret
 456 EndProc SetBad
 457 ;
 458 ; BadCall is the initial routine for bad function calls
 459 ;
 460 procedure   BadCall,FAR
 461         call    SetBad
 462         ret
 463 EndProc BadCall
 464 ;
 465 ; OKCall always sets carry to off.
 466 ;
 467 Procedure   OKCall,FAR
 468         ASSUME  CS:DOSGROUP,DS:NOTHING,ES:NOTHING,SS:NOTHING
 469         CLC
 470         ret
 471 EndProc OKCall
 472
 473 ; INT 2F handler works as follows:
 474 ;   PUSH    AX
 475 ;   MOV     AX,multiplex:function
 476 ;   INT     2F
 477 ;   POP     ...
 478 ; The handler itself needs to make the AX available for the various routines.
 479
 480 PUBLIC  Int2F
 481 INT2F   PROC    FAR
 482
 483 INT2FNT:
 484         ASSUME  CS:DOSGROUP,DS:NOTHING,ES:NOTHING,SS:NOTHING
 485         STI
 486         CMP     AH,multNET
 487         JNZ     INT2FSHR
 488 TestInstall:
 489         OR      AL,AL
 490         JZ      Leave2F
 491 BadFunc:
 492         CALL    SetBad
 493         entry   Leave2F
 494         RET     2                       ; long return + clear flags off stack
 495
 496 INT2FSHR:
 497         CMP     AH,multSHARE            ; is this a share request
 498         JZ      TestInstall             ; yes, check for installation
 499
 500 INT2FNLS:
 501         CMP     AH,NLSFUNC              ; is this a DOS 3.3 NLSFUNC request
 502         JZ      TestInstall             ; yes check for installation
 503
 504 INT2FDOS:
 505         ASSUME  CS:DOSGROUP,DS:NOTHING,ES:NOTHING,SS:NOTHING
 506         CMP     AH,multDOS
 507         JZ      DispatchDOS
 508         IRET                            ; This assume that we are at the head
 509                                         ; of the list
 510 INT2F   ENDP
 511
 512 DispatchDOS:
 513         PUSH    FOO                     ; push return address
 514         PUSH    DTab                    ; push table address
 515         PUSH    AX                      ; push index
 516         PUSH    BP
 517         MOV     BP,SP
 518 ; stack looks like:
 519 ;   0   BP
 520 ;   2   DISPATCH
 521 ;   4   TABLE
 522 ;   6   RETURN
 523 ;   8   LONG-RETURN
 524 ;   c   FLAGS
 525 ;   e   AX
 526
 527         MOV     AX,[BP+0Eh]             ; get AX value
 528         POP     BP
 529         Invoke  TableDispatch
 530         JMP     BadFunc                 ; return indicates invalid function
 531
 532 Procedure   INT2F_etcetera,NEAR
 533         entry   DosGetGroup
 534         PUSH    CS
 535         POP     DS
 536         return
 537
 538         entry   DOSInstall
 539         MOV     AL,0FFh
 540         return
 541 EndProc INT2F_etcetera
 542
 543 ENDIF
 544 ;Input: same as ABSDRD and ABSDWRT
 545 ;        ES:BP -> DPB
 546 ;Functions: convert 32bit absolute RW input parms to 16bit input parms
 547 ;Output: carry set when CX=-1 and drive is less then 32mb
 548 ;        carry clear, parms ok
 549 ;
 550 Procedure   RW32_CONVERT,NEAR
 551         ASSUME  CS:DOSGROUP,DS:NOTHING,ES:NOTHING,SS:NOTHING
 552         CMP     CX,-1                        ;>32mb  new format ?               ;AN000;
 553         JZ      new32format                  ;>32mb  yes                        ;AN000;
 554         PUSH    AX                           ;>32mb  save ax                    ;AN000;
 555         PUSH    DX                           ;>32mb  save dx                    ;AN000;
 556         MOV     AX,ES:[BP.dpb_max_cluster]   ;>32mb  get max cluster #          ;AN000;
 557         MOV     DL,ES:[BP.dpb_cluster_mask]  ;>32mb                             ;AN000;
 558         CMP     DL,0FEH                      ;>32mb  removable ?                ;AN000;
 559         JZ      letold                       ;>32mb  yes                        ;AN000;
 560         INC     DL                           ;>32mb                             ;AN000;
 561         XOR     DH,DH                        ;>32mb  dx = sector/cluster        ;AN000;
 562         MUL     DX                           ;>32mb  dx:ax= max sector #        ;AN000;
 563         OR      DX,DX                        ;>32mb  > 32mb ?                   ;AN000;
 564 letold:
 565         POP     DX                           ;>32mb  retore dx                  ;AN000;
 566         POP     AX                           ;>32mb  restore ax                 ;AN000;
 567         JZ      old_style                    ;>32mb  no                         ;AN000;
 568         MOV     [IFS_DRIVER_ERR],0207H       ;>32mb  error                      ;AN000;
 569         STC                                  ;>32mb                             ;AN000;
 570         return                               ;>32mb                             ;AN000;
 571 new32format:
 572         MOV     DX,WORD PTR [BX.SECTOR_RBA+2];>32mb                             ;AN000;
 573         MOV     [HIGH_SECTOR],DX             ;>32mb                             ;AN000;
 574         MOV     DX,WORD PTR [BX.SECTOR_RBA]  ;>32mb                             ;AN000;
 575         MOV     CX,[BX.ABS_RW_COUNT]         ;>32mb                             ;AN000;
 576         LDS     BX,[BX.BUFFER_ADDR]          ;>32mb                             ;AN000;
 577 old_style:                                   ;>32mb                             ;AN000;
 578         CLC                                  ;>32mb                             ;AN000;
 579         return                               ;>32mb                             ;AN000;
 580 EndProc RW32_CONVERT
 581
 582
 583 ;Input: None
 584 ;Functions: Purge Fastopen/seek Cache Buffers
 585 ;Output: None
 586 ;
 587 ;
 588 Procedure   Fastxxx_Purge,NEAR
 589         ASSUME  CS:DOSGROUP,DS:NOTHING,ES:NOTHING,SS:NOTHING
 590         PUSH    AX                            ; save regs.                      ;AN000;
 591         PUSH    SI                                                              ;AN000;
 592         PUSH    DX                                                              ;AN000;
 593         TEST    FastSeekflg,Fast_yes          ; fastseek installed ?            ;AN000;
 594         JZ      topen                         ; no                              ;AN000;
 595         MOV     AH,FastSeek_ID                ; set fastseek id                 ;AN000;
 596         JMP     SHORT dofast                  ;                                 ;AN000;
 597 topen:
 598         TEST    FastOpenflg,Fast_yes          ; fastopen installed ?            ;AN000;
 599         JZ      nofast                        ; no                              ;AN000;
 600         MOV     AH,FastOpen_ID                ; set fastseek installed          ;AN000;
 601 dofast:
 602         MOV     AL,FONC_purge                 ; purge                           ;AN000;
 603         MOV     DL,ES:[BP.dpb_drive]          ; set up drive number             ;AN000;
 604         invoke  Fast_Dispatch                 ; call fastopen/seek              ;AN000;
 605 nofast:
 606         POP     DX                                                              ;AN000;
 607         POP     SI                            ; restore regs                    ;AN000;
 608         POP     AX                            ;                                 ;AN000;
 609
 610         return                                ; exit                            ;AN000;
 611 EndProc Fastxxx_Purge
 612
 613 CODE    ENDS
 614 \1a