178 lines
6.2 KiB
PHP
178 lines
6.2 KiB
PHP
; PAGE 80,132
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.xall
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; Revision History:
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;
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; M003 - added A20OFF_FLAG for MS PASCAL 3.2 compatibility support
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; for DOS5.X running in HMA.
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;
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; M004 - added bit definition SETSSSP for DOS_FLAG for supporting
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; exe files without stack segment.
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; This is no longer needed as we modify SP only. Removing
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; this equate. 9/26/90
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;
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; M009 - addded comments relating to mace mkeyrate ver 1.0 support
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; with DOS in HMA.
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;
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; M025 - Added SWITCHES=/W for suppressing mandatory loading
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; of WINA20.386
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;
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; M027 - Support for copy protected apps. Defined bit 2 of DOS_FLAG
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;
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TRUE EQU 0FFFFh
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FALSE EQU 0
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Installed = TRUE
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IFNDEF DEBUG
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DEBUG = FALSE
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ENDIF
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include dbcs.sw
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include dosmac.INC
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include VERSIONA.INC
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include VERSION.INC
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BREAK <Control character definitions>
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c_DEL EQU 7Fh ; ASCII rubout or delete previous char
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c_BS EQU 08h ; ^H ASCII backspace
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c_CR EQU 0Dh ; ^M ASCII carriage return
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c_LF EQU 0Ah ; ^J ASCII linefeed
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c_ETB EQU 17h ; ^W ASCII end of transmission
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c_NAK EQU 15h ; ^U ASCII negative acknowledge
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c_ETX EQU 03h ; ^C ASCII end of text
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c_HT EQU 09h ; ^I ASCII tab
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BREAK <Read This and Weep>
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include buffer.INC
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BREAK <User stack inside of system call and SysVars>
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; Location of user registers relative user stack pointer
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user_environ STRUC
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user_AX DW ? ; 00 hex offsets to
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user_BX DW ? ; 02 facilitate debugging
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user_CX DW ? ; 04
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user_DX DW ? ; 06
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user_SI DW ? ; 08
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user_DI DW ? ; 0A
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user_BP DW ? ; 0C
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user_DS DW ? ; 0E
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user_ES DW ? ; 10
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user_IP DW ? ; 12
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user_CS DW ? ; 14
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user_F DW ? ; 16
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user_environ ENDS
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BREAK <Disk map>
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; MSDOS partitions the disk into 4 sections:
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;
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; phys sector 0: +-------------------+
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; | | boot/reserved |
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; | +-------------------+
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; | | File allocation |
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; v | table(s) |
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; | (multiple copies |
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; | are kept) |
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; +-------------------+
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; | Directory |
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; +-------------------+
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; | File space |
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; +-------------------+
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; | Unaddressable |
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; | (to end of disk) |
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; +-------------------+
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;
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; All partition boundaries are sector boundaries. The size of the FAT is
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; adjusted to maximize the file space addressable.
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include dirent.INC
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BREAK <File allocation Table information>
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;
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; The File Allocation Table uses a 12-bit entry for each allocation unit on
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; the disk. These entries are packed, two for every three bytes. The contents
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; of entry number N is found by 1) multiplying N by 1.5; 2) adding the result
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; to the base address of the Allocation Table; 3) fetching the 16-bit word
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; at this address; 4) If N was odd (so that N*1.5 was not an integer), shift
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; the word right four bits; 5) mask to 12 bits (AND with 0FFF hex). Entry
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; number zero is used as an end-of-file trap in the OS and is passed to the
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; BIOS to help determine disk format. Entry 1 is reserved for future use.
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; The first available allocation unit is assigned entry number two, and even
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; though it is the first, is called cluster 2. Entries greater than 0FF8H
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; (12-bit fats) or 0FFF8H (16-bit fats) are end of file marks; entries of zero
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; are unallocated. Otherwise, the contents of a FAT entry is the number of
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; the next cluster in the file.
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;
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; Clusters with bad sectors are tagged with FF7H. Any non-zero number would
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; do because these clusters show as allocated, but are not part of any
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; allocation chain and thus will never be allocated to a file. A particular
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; number is selected so that disk checking programs know what to do (ie. a
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; cluster with entry FF7H which is not in a chain is not an error).
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;** Character Type Flags
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;
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; These flags are used in a lookup table indexed by the character code.
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; They're used to quickly classify characters when parsing paths.
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; I think that these are only used to parse FCBs - jgl
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FCHK equ 1 ; I think this means "normal name char, no chks needed" -jgl
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FDELIM equ 2 ; is a delimiter
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FSPCHK equ 4 ; set if character is not a space or equivalent
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FFCB equ 8 ; is valid in an FCB
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include error.INC
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;** Bit definitions for DOS_FLAG
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;
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; Bit 0 - this is set when a $open call is made from $exec. This is used in
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; $open to indicate to the redirector that this open is being made
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; by an exec call.
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;
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; Bit 2
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;
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; M003, M027:
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;
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; The start up code of MS PASCAL 3.2 programs depend on the 1M address wrap
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; if they load below 64K. This is a likely possiblity in DOS 5.x with DOS in
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; the HMA. By default DOS will turn A20 OFF before Xferring control to the
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; user program in the case of an Exec call. The next call to DOS will turn
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; A20 line ON. It has been observed that MS PASCAL 3.2 start up does an int
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; 21 ah=25h call before executing the faulty code. This will turn A20 On.
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; In order to support this we will set Bit 2 of this flag in the DOS exec
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; call (msproc.asm) if DOS is running in the HMA. In $set_interrupt_vector in
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; getset.asm A20OFF_COUNT is set to 1 if bit 2 of DOS_FLAG was previously set
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; by a call to exec and if A20OFF_COUNT is 0. In msdisp.asm, if A20OFF_COUNT
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; is non zero then A20 will be turned OFF before returning to the user.
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; Bit 2 will be unconditionally cleared here.
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;
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; M009, M027:
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;
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; Mace utilities MKEYRATE.COM version 1.0 copyright 1987 is an execpacked
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; program converted to a com file. Therefore if DOS is loaded high and if
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; this program is loaded below 64K it will blurt out "packed file is corrupt".
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; This program does an int 21 ah=49h before executing the buggy execpacked
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; code. This int21 call turns a20 on and hence the problem. In $dealloc
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; alloc.asm A20OFF_COUNT is set to 1 if bit 2 of DOS_FLAG was previously set
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; by a call to exec and if A20OFF_COUNT is 0. In msdisp.asm, if A20OFF_COUNT
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; is non zero then A20 will be turned OFF before returning to the user.
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; Bit 2 will be unconditionally cleared here.
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;
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;
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;
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EXECOPEN EQU 00000001b ; bit 0 of DOS_FLAG
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SUPPRESS_WINA20 EQU 00000010b ; M025
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EXECA20OFF EQU 00000100b ; bit 2 of DOS_FLAG
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