The Programmer's Guide to TRSDOS Version 6 - Tim Mann's Home ...

Bit 7 Set to "1" if DEBUG is to be turned on after the execution of the program
just loaded for execution. The use is internal to the system. If DEBUG is
active, the DOS will not enter DEBUG when running an EXEC-only program but
will maintain the DEBUG status via this bit.
TFLAG$
This is the machine type flag. It's value indicates the computer model running the
DOS. Some of the typical TRS-80 values are: 2 = model 2; 4 = model 4; 5 = model
4P; 12 = model 12; 16 = model 16.
UFLAG$
This is a user flag. It is available for whatever purpose you wish to make of it.
It will remain unused by the system; however, the flag contents will be part of
any SYSGEN configuration file.
VFLAG$
Bits 0-3 Are used in controlling the cursor blink rate.
Bit 4 If set, the clock will be displayed on the video screen.
Bit 5 This bit is used by the system to toggle the cursor state.
Bit 6 If set, the cursor is non-blinking; otherwise blinking.
Bit 7 Used by the system to suppress blinking while in the *DO driver to inhibit
the blink task from changing state.
WFLAG$
This is a machine dependent flag commonly used to store an image of mode-1
interrupt masking. For instance, on the TRS-80 Model 4, it stores an image of the
WRINTMASK register (E0).
OTHER DATA
The other system information accessible relative to the flags pointer is as
follows:
FLAGS-47 contains the release number of the DOS (OSRLS$). For instance, OSRLS$ is
X'10' for version/release 6.0.1 (see FLAGS+27 for the version).
FLAGS-1 contains the overlay entry number of the system overlay currently resident
in the overlay region. The low-order four bits reference the overlay number (1-
13).
FLAGS+26 contains a one-byte pointer to the memory page which contains the SVC
vector table (SVCTAB). This is useful to hook into system routines by indexing
into the proper SVCTAB position according to the SVC number. The SVCTAB is always
located on a page boundary.
FLAGS+27 contains the version number of the DOS (OSVER$). For instance, OSVER$ is
X'62' for version 6.2.x
FLAGS+28 through FLAGS+30 contain a jump vector for @ICNFG. See the Chapter 8, the
Appendix, on @ICNFG interfacing for details on this vector.
FLAGS+31 through FLAGS+33 contain a jump vector for @KITSK. See Chapter 8, the
Appendix, on @KITSK interfacing for details on this vector.
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