v2.0/source/COMMAND.ASM

   1 ;
   2 ; This version of COMMAND is divided into three distinct parts.  First is the
   3 ; resident portion, which includes handlers for interrupts 22H (terminate),
   4 ; 23H (Cntrl-C), 24H (fatal error), and 27H (stay resident); it also has code
   5 ; to test and, if necessary, reload the transient portion.  Following the
   6 ; resident is the init code, which is overwritten after use.  Then comes the
   7 ; transient portion, which includes all command processing (whether internal
   8 ; or external).  The transient portion loads at the end of physical memory,
   9 ; and it may be overlayed by programs that need as much memory as possible.
  10 ; When the resident portion of command regains control from a user program, a
  11 ; checksum is performed on the transient portion to see if it must be
  12 ; reloaded.  Thus programs which do not need maximum memory will save the time
  13 ; required to reload COMMAND when they terminate.
  14
  15 ;
  16 ; REV 1.17
  17 ;    05/19/82   Fixed bug in BADEXE error (relocation error must return to
  18 ;               resident since the EXELOAD may have overwritten the transient.
  19 ; REV 1.18
  20 ;    05/21/82   IBM version always looks on drive A
  21 ;               MSVER always looks on default drive
  22 ;
  23 ; REV 1.19
  24 ;    06/03/82   Drive spec now entered in command line
  25 ;    06/07/82   Added VER command (print DOS version number) and VOL command
  26 ;               (print volume label)
  27 ; REV 1.20
  28 ;    06/09/82   Prints "directory" after directories
  29 ;    06/13/82   MKDIR, CHDIR, PWD, RMDIR added
  30 ; REV 1.50
  31 ;               Some code for new 2.0 DOS, sort of HACKey.  Not enough time to
  32 ;               do it right.
  33 ; REV 1.70
  34 ;               EXEC used to fork off new processes
  35 ; REV 1.80
  36 ;               C switch for single command execution
  37 ; REV 1.90
  38 ;               Batch uses XENIX
  39 ; Rev 2.00
  40 ;               Lots of neato stuff
  41 ;               IBM 2.00 level
  42 ; Rev 2.01
  43 ;               'D' switch for date time suppression
  44 ; Rev 2.02
  45 ;               Default userpath is NUL rather than BIN
  46 ;                       same as IBM
  47 ;               COMMAND split into pieces
  48 ; Rev 2.10
  49 ;               INTERNATIONAL SUPPORT
  50 ; Rev 2.11      COMMAND split into more pieces
  51
  52         INCLUDE DOSSYM.ASM
  53         INCLUDE DEVSYM.ASM
  54         INCLUDE COMSW.ASM
  55         INCLUDE COMEQU.ASM
  56
  57 CODERES SEGMENT PUBLIC
  58 CODERES ENDS
  59
  60 DATARES SEGMENT PUBLIC BYTE
  61         EXTRN   COMBAD:BYTE,NEEDCOM:BYTE,DRVMSG:BYTE
  62         EXTRN   DEFMSG:BYTE,PROMPT:BYTE,EXECEMES:BYTE,EXEBAD:BYTE
  63         EXTRN   TOOBIG:BYTE,NOCOM:BYTE,RBADNAM:BYTE,INT_2E_RET:DWORD
  64         EXTRN   NOHANDMES:BYTE,BMEMMES:BYTE,HALTMES:BYTE,FRETMES:BYTE
  65         EXTRN   PARENT:WORD,HANDLE01:WORD,LOADING:BYTE,BATCH:WORD
  66         EXTRN   TRNSEG:WORD,COMDRV:BYTE,MEMSIZ:WORD,SUM:WORD,EXTCOM:BYTE
  67         EXTRN   IO_SAVE:WORD,PERMCOM:BYTE,SINGLECOM:WORD,VERVAL:WORD
  68         EXTRN   PIPEFLAG:BYTE,SAVE_PDB:WORD,COMSPEC:BYTE,TRANS:WORD
  69         EXTRN   TRANVARS:BYTE,LTPA:WORD,RSWITCHAR:BYTE,RDIRCHAR:BYTE
  70         EXTRN   RETCODE:WORD,FORFLAG:BYTE
  71
  72         IF      IBMVER
  73         EXTRN   SYS_CALL:DWORD,ZEXEC:WORD,EXESEG:WORD,EXESUM:WORD
  74         EXTRN   USER_SS:WORD,USER_SP:WORD
  75         ENDIF
  76
  77 DATARES ENDS
  78
  79 ENVIRONMENT SEGMENT PUBLIC PARA        ; Default COMMAND environment
  80 ENVIRONMENT ENDS
  81
  82 INIT    SEGMENT PUBLIC PARA
  83         EXTRN   CONPROC:NEAR
  84 INIT    ENDS
  85
  86 TAIL    SEGMENT PUBLIC PARA
  87 TAIL    ENDS
  88
  89 TRANCODE        SEGMENT PUBLIC PARA
  90 TRANCODE        ENDS
  91
  92 TRANDATA        SEGMENT PUBLIC BYTE
  93         EXTRN   TRANDATAEND:BYTE
  94 TRANDATA        ENDS
  95
  96 TRANSPACE       SEGMENT PUBLIC BYTE
  97         EXTRN   TRANSPACEEND:BYTE,HEADCALL:DWORD
  98 TRANSPACE       ENDS
  99
 100 TRANTAIL        SEGMENT PUBLIC PARA
 101 TRANTAIL        ENDS
 102
 103 ZEXEC_CODE      SEGMENT PUBLIC PARA
 104 ZEXEC_CODE      ENDS
 105
 106 ZEXEC_DATA      SEGMENT PUBLIC BYTE
 107 ZEXEC_DATA      ENDS
 108
 109 RESGROUP        GROUP   CODERES,DATARES,ENVIRONMENT,INIT,TAIL
 110 TRANGROUP       GROUP   TRANCODE,TRANDATA,TRANSPACE,TRANTAIL
 111 EGROUP          GROUP   ZEXEC_CODE,ZEXEC_DATA
 112
 113 ENVIRONMENT SEGMENT PUBLIC PARA        ; Default COMMAND environment
 114
 115         PUBLIC  ECOMSPEC,ENVIREND,PATHSTRING
 116
 117         ORG     0
 118 ENVARENA DB     10H DUP (?)     ; Pad for mem arena
 119 PATHSTRING DB   "PATH="
 120 USERPATH LABEL  BYTE
 121
 122         DB      0               ; Null path
 123         DB      "COMSPEC="
 124 ECOMSPEC DB     "/COMMAND.COM"
 125         DB      134 DUP (0)
 126
 127 ENVIREND        LABEL   BYTE
 128
 129 ENVIRONSIZ EQU  $-PATHSTRING
 130 ENVIRONSIZ2 EQU $-ECOMSPEC
 131 ENVIRONMENT ENDS
 132
 133
 134 ; START OF RESIDENT PORTION
 135
 136 CODERES SEGMENT PUBLIC
 137
 138         PUBLIC  GETCOMDSK2,LODCOM,THEADFIX,CONTCTERM,LOADCOM,INT_2E,LODCOM1
 139         PUBLIC  CHKSUM,SETVECT,EXT_EXEC,TREMCHECK,RESTHAND,CONTC,RSTACK
 140         PUBLIC  SAVHAND
 141
 142         IF      IBMVER
 143         PUBLIC  EXECHK,SYSCALL,EXEC_WAIT
 144         ENDIF
 145
 146 ASSUME  CS:RESGROUP,DS:NOTHING,ES:NOTHING,SS:NOTHING
 147
 148         EXTRN   RPRINT:NEAR,ASKEND:NEAR,DSKERR:NEAR
 149
 150
 151         ORG     0
 152 ZERO    =       $
 153
 154         ORG     100H
 155
 156 PROGSTART:
 157         JMP     RESGROUP:CONPROC
 158
 159         DB      (80H - 3) DUP (?)
 160 RSTACK  LABEL   WORD
 161
 162 IF IBMVER
 163 SYSCALL:
 164         CMP     AH,EXEC
 165         JZ      do_exec
 166         JMP     DWORD PTR [SYS_CALL]
 167
 168 do_exec:
 169         PUSH    ES
 170         PUSH    DS
 171         PUSH    BP
 172         PUSH    DI
 173         PUSH    SI
 174         PUSH    DX
 175         PUSH    CX
 176         PUSH    BX
 177         PUSH    AX
 178         MOV     [user_ss],SS
 179         MOV     [user_sp],SP
 180 ;
 181 ; are we running on RSTACK already?
 182 ;
 183         PUSH    CS
 184         POP     BX              ; BX <- CS
 185         PUSH    SS
 186         POP     AX              ; AX <- SS
 187         CMP     AX,BX           ; IF AX == BX then no stack switch!
 188         JZ      Get_mem
 189         MOV     SS,BX
 190 ASSUME  SS:RESGROUP
 191         MOV     SP,OFFSET RESGROUP:RSTACK
 192
 193 Get_mem:
 194         MOV     BX,0FFFFH       ; allocate all of memory
 195         MOV     AH,ALLOC
 196         INT     int_command
 197         MOV     AX,OFFSET EGROUP:ZEXECDATAEND + 15
 198         MOV     CL,4
 199         SHR     AX,CL
 200         MOV     CX,AX          ; Save in CX
 201         CMP     BX,AX          ; enough for EXEC?
 202         JB      EXECMER        ; nope... cry
 203         MOV     AH,ALLOC
 204         INT     int_command
 205         JC      EXECMER         ; Memory arenas probably trashed
 206         ADD     BX,AX
 207         MOV     [MEMSIZ],BX
 208         SUB     BX,CX
 209         MOV     [EXESEG],BX     ; exec
 210         MOV     ES,AX
 211         MOV     AH,DEALLOC
 212         INT     int_command
 213         PUSH    CS
 214         POP     DS
 215 ASSUME  DS:RESGROUP
 216         CALL    EXECHK
 217         CMP     DX,[EXESUM]
 218         JZ      HAVEXEC         ; EXEC OK
 219         MOV     DX,OFFSET RESGROUP:COMSPEC
 220         MOV     AX,OPEN SHL 8
 221         INT     int_command             ; Open COMMAND.COM
 222         JC      EXECMER
 223         MOV     BX,AX           ; Handle
 224         MOV     DX,OFFSET RESGROUP:TRANSTART
 225         ADD     DX,OFFSET TRANGROUP:EXECSTART - 100H
 226         XOR     CX,CX           ; Seek loc
 227         MOV     AX,LSEEK SHL 8
 228         INT     int_command
 229         MOV     CX,OFFSET EGROUP:ZEXECCODEEND
 230         MOV     DS,[EXESEG]
 231 ASSUME  DS:NOTHING
 232         MOV     AH,READ
 233         INT     int_command
 234         PUSH    AX
 235         MOV     AH,CLOSE
 236         INT     int_command             ; Close COMMAND.COM
 237         POP     CX
 238         CMP     CX,OFFSET EGROUP:ZEXECCODEEND
 239         JNZ     EXECMER         ; Size matched
 240
 241         CALL    EXECHK
 242         CMP     DX,[EXESUM]
 243         JNZ     EXECMER
 244 HAVEXEC:
 245         MOV     [LOADING],0             ; Flag to DSKERR
 246         CALL    DWORD PTR [ZEXEC]
 247         JMP     SHORT EXECRET
 248 execmer:
 249         LDS     SI,DWORD PTR [user_Sp]
 250         MOV     [SI.user_AX],exec_not_enough_memory
 251         PUSH    [SI.user_F]
 252         POPF
 253         STC
 254         PUSHF
 255         POP     [SI.user_F]
 256 execret:
 257         MOV     SS,[user_SS]
 258 ASSUME  SS:NOTHING
 259         MOV     SP,[user_SP]
 260         POP     AX              ; PUSH    ES
 261         POP     BX              ; PUSH    DS
 262         POP     CX              ; PUSH    BP
 263         POP     DX              ; PUSH    DI
 264         POP     SI              ; PUSH    SI
 265         POP     DI              ; PUSH    DX
 266         POP     BP              ; PUSH    CX
 267         POP     DS              ; PUSH    BX
 268         POP     ES              ; PUSH    AX
 269         IRET
 270
 271 EXECHK:
 272 ASSUME  DS:NOTHING,ES:NOTHING,SS:NOTHING
 273         PUSH    DS
 274         MOV     DS,[EXESEG]
 275         MOV     CX,OFFSET EGROUP:ZEXECCODEEND
 276         XOR     SI,SI
 277         JMP     CHECK_SUM
 278 ENDIF
 279
 280 EXEC_ERR:                       ; Select the correct error message
 281         MOV     DX,OFFSET RESGROUP:RBADNAM
 282         CMP     AX,exec_file_not_found
 283         JZ      GOTEXECEMES
 284         CMP     AX,error_access_denied
 285         JZ      GOTEXECEMES
 286         MOV     DX,OFFSET RESGROUP:TOOBIG
 287         CMP     AX,exec_not_enough_memory
 288         JZ      GOTEXECEMES
 289         MOV     DX,OFFSET RESGROUP:EXEBAD
 290         CMP     AX,exec_bad_format
 291         JZ      GOTEXECEMES
 292         MOV     DX,OFFSET RESGROUP:EXECEMES
 293 GOTEXECEMES:
 294         PUSH    CS
 295         POP     DS
 296         CALL    RPRINT
 297         JMP     SHORT NOEXEC
 298
 299 EXT_EXEC:
 300 ;
 301 ; we are now running in free space.  anything we do from here
 302 ; on may get trashed.  Move the stack (also in free space) to
 303 ; allocated space because since EXEC restores the stack,
 304 ; somebody may trash what is on the stack.
 305 ;
 306         MOV     CX,CS
 307         MOV     SS,CX
 308         MOV     SP,OFFSET RESGROUP:RSTACK
 309 ;
 310 ; Oops!! We have to make sure that the EXEC code doesn't blop a newstack!
 311 ;
 312 ;
 313         INT     int_command     ; Do the EXEC
 314         JC      EXEC_ERR        ; EXEC failed
 315 EXEC_WAIT:
 316         MOV     AH,WAIT
 317         INT     int_command     ; Get the return code
 318         MOV     [RETCODE],AX
 319 NOEXEC:
 320         JMP     LODCOM
 321
 322 CONTC:
 323         STI
 324         MOV     AX,CS
 325         MOV     DS,AX
 326 ASSUME  DS:RESGROUP
 327         MOV     AH,DISK_RESET
 328         INT     int_command     ; Reset disks in case files were open
 329         TEST    [BATCH],-1
 330         JZ      CONTCTERM
 331         JMP     ASKEND          ; See if user wants to terminate batch
 332 CONTCTERM:
 333         XOR     BP,BP           ; Indicate no read
 334         MOV     [FORFLAG],0     ; Turn off for processing
 335         MOV     [PIPEFLAG],0    ; Turn off any pipe
 336         CMP     [SINGLECOM],0   ; See if we need to set SINGLECOM
 337         JZ      NOSETSING
 338         MOV     [SINGLECOM],-1  ; Cause termination on pipe, batch, for
 339 NOSETSING:
 340         CMP     [EXTCOM],0
 341         JNZ     DODAB           ; Internal ^C
 342         JMP     LODCOM1
 343 DODAB:
 344         STC                     ; Tell DOS to abort
 345 ZZY     PROC    FAR
 346         RET                     ; Leave flags on stack
 347 ZZY     ENDP
 348
 349 BADMEMERR:                              ; Allocation error loading transient
 350         MOV     DX,OFFSET RESGROUP:BMEMMES
 351 FATALC:
 352         PUSH    CS
 353         POP     DS
 354         CALL    RPRINT
 355         CMP     [PERMCOM],0
 356         JZ      FATALRET
 357         CMP     [SINGLECOM],0                   ; If PERMCOM and SINGLECOM
 358         JNZ     FATALRET                        ; Must take INT_2E exit
 359         MOV     DX,OFFSET RESGROUP:HALTMES
 360         CALL    RPRINT
 361 STALL:
 362         JMP     STALL                           ; Crash the system nicely
 363
 364 FATALRET:
 365         MOV     DX,OFFSET RESGROUP:FRETMES
 366         CALL    RPRINT
 367 FATALRET2:
 368         CMP     [PERMCOM],0                     ; If we get here and PERMCOM,
 369         JNZ     RET_2E                          ; must be INT_2E
 370 IF IBM
 371         LDS     DX,DWORD PTR [SYS_CALL]
 372 ASSUME  DS:NOTHING
 373         MOV     AX,(SET_INTERRUPT_VECTOR SHL 8) + INT_COMMAND
 374         INT     int_command
 375 ENDIF
 376         MOV     AX,[PARENT]
 377         MOV     WORD PTR CS:[PDB_Parent_PID],AX
 378         MOV     AX,(EXIT SHL 8)                 ; Return to lower level
 379         INT     int_command
 380
 381 RET_2E:
 382         PUSH    CS
 383         POP     DS
 384 ASSUME  DS:RESGROUP,ES:NOTHING,SS:NOTHING
 385         MOV     [SINGLECOM],0   ; Turn off singlecom
 386         MOV     ES,[LTPA]
 387         MOV     AH,DEALLOC
 388         INT     int_command             ; Free up space used by transient
 389         MOV     BX,[SAVE_PDB]
 390         MOV     AH,SET_CURRENT_PDB
 391         INT     int_command             ; Current process is user
 392         MOV     AX,[RETCODE]
 393         CMP     [EXTCOM],0
 394         JNZ     GOTECODE
 395         XOR     AX,AX           ; Internals always return 0
 396 GOTECODE:
 397         MOV     [EXTCOM],1      ; Force external
 398         JMP     [INT_2E_RET]    ;"IRET"
 399
 400 INT_2E:                         ; Magic command executer
 401 ASSUME  DS:NOTHING,ES:NOTHING,SS:NOTHING
 402         POP     WORD PTR [INT_2E_RET]
 403         POP     WORD PTR [INT_2E_RET+2]    ;Get return address
 404         POP     AX              ;Chuck flags
 405         PUSH    CS
 406         POP     ES
 407         MOV     DI,80H
 408         MOV     CX,64
 409         REP     MOVSW
 410         MOV     AH,GET_CURRENT_PDB
 411         INT     int_command             ; Get user's header
 412         MOV     [SAVE_PDB],BX
 413         MOV     AH,SET_CURRENT_PDB
 414         MOV     BX,CS
 415         INT     int_command             ; Current process is me
 416         MOV     [SINGLECOM],81H
 417         MOV     [EXTCOM],1      ; Make sure this case forced
 418
 419 LODCOM:                         ; Termination handler
 420         CMP     [EXTCOM],0
 421         JZ      LODCOM1         ; If internal, memory already allocated
 422         MOV     BX,0FFFFH
 423         MOV     AH,ALLOC
 424         INT     int_command
 425         MOV     AX,OFFSET TRANGROUP:TRANSPACEEND + 15
 426         MOV     CL,4
 427         SHR     AX,CL
 428
 429         IF      IBM
 430         PUSH    AX
 431         MOV     AX,OFFSET EGROUP:ZEXECDATAEND + 15
 432         MOV     CL,4
 433         SHR     AX,CL
 434         POP     CX
 435         ADD     AX,CX
 436         ENDIF
 437
 438         ADD     AX,20H
 439         CMP     BX,AX           ; Is less than 512 byte buffer worth it?
 440         JNC     MEMOK
 441 BADMEMERRJ:
 442         JMP BADMEMERR           ; Not enough memory
 443 MEMOK:
 444         MOV     AH,ALLOC
 445         INT     int_command
 446         JC      BADMEMERRJ      ; Memory arenas probably trashed
 447         MOV     [EXTCOM],0      ; Flag not to ALLOC again
 448         MOV     [LTPA],AX       ; New TPA is base just allocated
 449         ADD     BX,AX
 450         MOV     [MEMSIZ],BX
 451
 452         MOV     AX,OFFSET TRANGROUP:TRANSPACEEND + 15
 453         MOV     CL,4
 454         SHR     AX,CL
 455
 456         IF      IBM
 457         PUSH    AX
 458         MOV     AX,OFFSET EGROUP:ZEXECDATAEND + 15
 459         MOV     CL,4
 460         SHR     AX,CL
 461         POP     CX
 462         ADD     AX,CX
 463         ENDIF
 464
 465         SUB     BX,AX
 466         MOV     [TRNSEG],BX     ; Transient starts here
 467 LODCOM1:
 468         MOV     AX,CS
 469         MOV     SS,AX
 470 ASSUME  SS:RESGROUP
 471         MOV     SP,OFFSET RESGROUP:RSTACK
 472         MOV     DS,AX
 473 ASSUME  DS:RESGROUP
 474         CALL    HEADFIX     ; Make sure files closed stdin and stdout restored
 475         XOR     BP,BP           ; Flag command ok
 476         MOV     AX,-1
 477         XCHG    AX,[VERVAL]
 478         CMP     AX,-1
 479         JZ      NOSETVER
 480         MOV     AH,SET_VERIFY_ON_WRITE  ; AL has correct value
 481         INT     int_command
 482 NOSETVER:
 483         CMP     [SINGLECOM],-1
 484         JNZ     NOSNG
 485         JMP     FATALRET2       ; We have finished the single command
 486 NOSNG:
 487         CALL    SETVECT
 488
 489 IF IBMVER
 490         CALL    EXECHK          ; Check exe loader
 491         CMP     DX,[EXESUM]
 492         JNZ     BOGUS_COM
 493 ENDIF
 494
 495         CALL    CHKSUM          ; Check the transient
 496         CMP     DX,[SUM]
 497         JZ      HAVCOM          ; Transient OK
 498 BOGUS_COM:
 499         MOV     [LOADING],1     ; Flag DSKERR routine
 500         CALL    LOADCOM
 501 CHKSAME:
 502
 503 IF IBMVER
 504         CALL    EXECHK
 505         CMP     DX,[EXESUM]
 506         JNZ     ALSO_BOGUS
 507 ENDIF
 508
 509         CALL    CHKSUM
 510         CMP     DX,[SUM]
 511         JZ      HAVCOM          ; Same COMMAND
 512 ALSO_BOGUS:
 513         CALL    WRONGCOM
 514         JMP     SHORT CHKSAME
 515 HAVCOM:
 516         MOV     AX,CHAR_OPER SHL 8
 517         INT     int_command
 518         MOV     [RSWITCHAR],DL
 519         CMP     DL,'/'
 520         JNZ     USESLASH
 521         MOV     [RDIRCHAR],'\'          ; Select alt path separator
 522 USESLASH:
 523         MOV     [LOADING],0             ; Flag to DSKERR
 524         MOV     SI,OFFSET RESGROUP:TRANVARS
 525         MOV     DI,OFFSET TRANGROUP:HEADCALL
 526         MOV     ES,[TRNSEG]
 527         CLD
 528         MOV     CX,8
 529         REP     MOVSW                   ; Transfer INFO to transient
 530         MOV     AX,[MEMSIZ]
 531         MOV     WORD PTR DS:[PDB_block_len],AX  ; Adjust my own header
 532         JMP     DWORD PTR [TRANS]
 533
 534 ; Far call to REMCHECK for TRANSIENT
 535 TREMCHECK PROC   FAR
 536         CALL    REMCHECK
 537         RET
 538 TREMCHECK ENDP
 539
 540 REMCHECK:
 541 ;All registers preserved. Returns zero if media removable, NZ if fixed
 542 ; AL is drive (0=DEF, 1=A,...)
 543         IF      IBM
 544         PUSH    AX
 545         OR      AL,AL
 546         JNZ     GOTDRV2
 547         MOV     AH,GET_DEFAULT_DRIVE
 548         INT     int_command
 549         INC     AL              ;A=1
 550 GOTDRV2:
 551         PUSH    BX
 552         MOV     BL,AL
 553         INT     11H             ;IBM EQUIP CALL
 554         ROL     AL,1
 555         ROL     AL,1
 556         AND     AL,3
 557         JNZ     NOT_SINGLE
 558         INC     AL
 559 NOT_SINGLE:
 560         INC     AL              ; AL is now MAX floppy #
 561         CMP     BL,AL
 562         POP     BX
 563         JBE     SETREM          ; Is an IBM floppy and so is removable
 564         OR      AL,AL           ; Know AL is non-zero
 565         JMP     SHORT SETNREM
 566 SETREM:
 567         ELSE
 568         PUSH    AX
 569         ENDIF
 570
 571         XOR     AX,AX           ;Zero
 572
 573         IF      IBM
 574 SETNREM:
 575         ENDIF
 576
 577         POP     AX
 578         RET
 579
 580 ; Far call to HEADFIX for TRANSIENT
 581 THEADFIX PROC   FAR
 582         CALL    HEADFIX
 583         RET
 584 THEADFIX ENDP
 585
 586 HEADFIX:
 587         XOR     BX,BX           ; Clean up header
 588         MOV     CX,[IO_SAVE]
 589         MOV     DX,WORD PTR DS:[PDB_JFN_Table]
 590         CMP     CL,DL
 591         JZ      CHK1            ; Stdin matches
 592         MOV     AH,CLOSE
 593         INT     int_command
 594         MOV     DS:[PDB_JFN_Table],CL   ; Restore stdin
 595 CHK1:
 596         INC     BX
 597         CMP     CH,DH           ; Stdout matches
 598         JZ      CHKOTHERHAND
 599         MOV     AH,CLOSE
 600         INT     int_command
 601         MOV     DS:[PDB_JFN_Table+1],CH ; Restore stdout
 602 CHKOTHERHAND:
 603         ADD     BX,4                    ; Skip 2,3,4
 604         MOV     CX,FilPerProc - 5       ; Already done 0,1,2,3,4
 605 CLOSELOOP:
 606         MOV     AH,CLOSE
 607         INT     int_command
 608         INC     BX
 609         LOOP    CLOSELOOP
 610         RET
 611
 612 SAVHAND:
 613 ASSUME  DS:NOTHING,ES:NOTHING,SS:NOTHING
 614         PUSH    DS
 615         PUSH    BX              ; Set stdin to sterr, stdout to stderr
 616         PUSH    AX
 617         MOV     AH,GET_CURRENT_PDB
 618         INT     int_command             ; Get user's header
 619         MOV     DS,BX
 620         MOV     AX,WORD PTR DS:[PDB_JFN_Table]
 621         MOV     [HANDLE01],AX           ; Save user's stdin, stdout
 622         MOV     AL,DS:[PDB_JFN_Table+2]
 623         MOV     AH,AL
 624         MOV     WORD PTR DS:[PDB_JFN_Table],AX   ; Dup stderr
 625         POP     AX
 626         POP     BX
 627         POP     DS
 628         RET
 629
 630 ASSUME  DS:RESGROUP
 631 GETCOMDSK2:
 632         CALL    GETCOMDSK
 633         JMP     LODCOM1         ; Memory already allocated
 634
 635 RESTHAND:
 636         PUSH    DS
 637         PUSH    BX              ; Restore stdin, stdout to user
 638         PUSH    AX
 639         MOV     AH,GET_CURRENT_PDB
 640         INT     int_command             ; Point to user's header
 641         MOV     AX,[HANDLE01]
 642         MOV     DS,BX
 643 ASSUME DS:NOTHING
 644         MOV     WORD PTR DS:[PDB_JFN_Table],AX   ; Stuff his old 0 and 1
 645         POP     AX
 646         POP     BX
 647         POP     DS
 648         RET
 649 ASSUME DS:RESGROUP,SS:RESGROUP
 650
 651 HOPELESS:
 652         MOV     DX,OFFSET RESGROUP:NOCOM
 653         JMP     FATALC
 654
 655 GETCOMDSK:
 656         MOV     DX,OFFSET RESGROUP:NEEDCOM
 657 GETCOMDSK3:
 658         MOV     AL,[COMDRV]
 659         CALL    REMCHECK
 660         JNZ     HOPELESS                ;Non-removable media
 661         CALL    RPRINT
 662         MOV     DX,OFFSET RESGROUP:DRVMSG
 663         CMP     [COMDRV],0
 664         JNZ     GETCOM1
 665         MOV     DX,OFFSET RESGROUP:DEFMSG
 666 GETCOM1:
 667         CALL    RPRINT
 668         MOV     DX,OFFSET RESGROUP:PROMPT
 669         CALL    RPRINT
 670         CALL    GetRawFlushedByte
 671         RET
 672
 673 ; flush world and get raw input
 674 GetRawFlushedByte:
 675         MOV     AX,(STD_CON_INPUT_FLUSH SHL 8) OR RAW_CON_INPUT
 676         INT     int_command             ; Get char without testing or echo
 677         MOV     AX,(STD_CON_INPUT_FLUSH SHL 8) + 0
 678         INT     int_command
 679         return
 680
 681 LOADCOM:                        ; Load in transient
 682         INC     BP              ; Flag command read
 683         MOV     DX,OFFSET RESGROUP:COMSPEC
 684         MOV     AX,OPEN SHL 8
 685         INT     int_command             ; Open COMMAND.COM
 686         JNC     READCOM
 687         CMP     AX,open_too_many_open_files
 688         JNZ     TRYDOOPEN
 689         MOV     DX,OFFSET RESGROUP:NOHANDMES
 690         JMP     FATALC          ; Fatal, will never find a handle
 691
 692 TRYDOOPEN:
 693         CALL    GETCOMDSK
 694         JMP     SHORT LOADCOM
 695
 696 READCOM:
 697         MOV     BX,AX           ; Handle
 698         MOV     DX,OFFSET RESGROUP:TRANSTART
 699         XOR     CX,CX           ; Seek loc
 700         MOV     AX,LSEEK SHL 8
 701         INT     int_command
 702         JC      WRONGCOM1
 703         MOV     CX,OFFSET TRANGROUP:TRANSPACEEND - 100H
 704
 705         IF      IBM
 706         ADD     CX,15
 707         AND     CX,0FFF0H
 708         ADD     CX,OFFSET EGROUP:ZEXECCODEEND
 709         ENDIF
 710
 711         PUSH    DS
 712         MOV     DS,[TRNSEG]
 713 ASSUME  DS:NOTHING
 714         MOV     DX,100H
 715         MOV     AH,READ
 716         INT     int_command
 717         POP     DS
 718 ASSUME  DS:RESGROUP
 719 WRONGCOM1:
 720         PUSHF
 721         PUSH    AX
 722         MOV     AH,CLOSE
 723         INT     int_command             ; Close COMMAND.COM
 724         POP     AX
 725         POPF
 726         JC      WRONGCOM        ; If error on READ
 727         CMP     AX,CX
 728         JZ      RET10           ; Size matched
 729 WRONGCOM:
 730         MOV     DX,OFFSET RESGROUP:COMBAD
 731         CALL    GETCOMDSK3
 732         JMP     SHORT LOADCOM   ; Try again
 733
 734 CHKSUM:                         ; Compute transient checksum
 735         PUSH    DS
 736         MOV     DS,[TRNSEG]
 737         MOV     SI,100H
 738         MOV     CX,OFFSET TRANGROUP:TRANDATAEND - 100H
 739
 740 CHECK_SUM:
 741         CLD
 742         SHR     CX,1
 743         XOR     DX,DX
 744 CHK:
 745         LODSW
 746         ADD     DX,AX
 747         LOOP    CHK
 748         POP     DS
 749 RET10:  RET
 750
 751 SETVECT:                        ; Set useful vectors
 752         MOV     DX,OFFSET RESGROUP:LODCOM
 753         MOV     AX,(SET_INTERRUPT_VECTOR SHL 8) OR 22H        ; Set Terminate address
 754         INT     int_command
 755         MOV     DX,OFFSET RESGROUP:CONTC
 756         MOV     AX,(SET_INTERRUPT_VECTOR SHL 8) OR 23H        ; Set Ctrl-C address
 757         INT     int_command
 758         MOV     DX,OFFSET RESGROUP:DSKERR
 759         MOV     AX,(SET_INTERRUPT_VECTOR SHL 8) OR 24H        ; Set Hard Disk Error address
 760         INT     int_command
 761         RET
 762
 763 CODERES ENDS
 764
 765 ; This TAIL segment is used to produce a PARA aligned label in the resident
 766 ; group which is the location where the transient segments will be loaded
 767 ; initial.
 768
 769 TAIL    SEGMENT PUBLIC PARA
 770         ORG     0
 771 TRANSTART       LABEL   WORD
 772 TAIL    ENDS
 773
 774 ; This TAIL segment is used to produce a PARA aligned label in the transient
 775 ; group which is the location where the exec segments will be loaded
 776 ; initial.
 777
 778 TRANTAIL    SEGMENT PUBLIC PARA
 779         ORG     0
 780 EXECSTART   LABEL   WORD
 781 TRANTAIL    ENDS
 782
 783 IF IBMVER
 784         INCLUDE EXEC.ASM
 785 ENDIF
 786
 787         END     PROGSTART
 788