Early mid August work

2023-08-13

This week some development of the debugger and of dosemu2 happened.

lDebug

Interrupt 0Dh, 0Ch hooks optional at run time (INSTALL INTFAULTS install flag noun)
Optional interrupt hooks share a lot of code now (1, 2, 3, 4)
In init the parsing of switches now capitalises the switch letter rather than doing two branches per switch
/P mode for path search in init (too many to list, view log here)
In init, push word [cs:…] replaced by using a temporary register (1, 2)
Bugfix: Auxiliary buffer size variables are initialised in bootloaded mode (bug on 2023-07-18)
Bugfix: If /2 switch specified but there is no second adapter, do not leave state halfway installed
Warning on unknown filename extension in init
Accept a no-op /D+ switch in lDDebug or /D- in lDebug
Add additional D*LEN variables (1) and DALLOCSEG and DALLOCSIZE (2)
Allow any separator after DDS to interpret command as D DS… rather than DD S…
Call dosemu2 helper function DOS_HELPER_PRESTROKES_START on interrupt 0E6h

dosemu2

Fix dl register passed to boot loader when -B switch is used
Fix output text in -quiet -dumb -te mode to no longer contain the mouse input reset escape sequences if machine didn't crash
Fix -input switch for keyboard input (1, 2)
Add feature to start keyboard input from -input only once DOS boot is complete, to avoid losing a keypress
Add related helper function to start keyboard input early, for entering input to booted lDebug

Enhanced DR-DOS

I went and investigated some bugs around the EDR-DOS int 21h functions 42h, 7142h, and 71A6h. (1, 2, 3, 4) To test this, I also built the latest EDR-DOS revision of 2011 from source.

ldosboot

One change to the test script's dosemu2 drive letter detection. However, this change only was needed because of the dosemu2 bug with the mouse data input reset escape sequences. It is actually the wrong way to do this, and consequently has been backed out.

ldosmbr

Some changes to the oldmbr:

Check the length of the MBR output file
Use the absolute $ trick instead of an equate for nobits data at 0:800h
Move the CHS geometry fields into nobits data as they don't need to be pre-initialised

One change to altmbr, today:

Check length of output

ldebug, dosemu2, edrdos, ldosboot, ldosmbr

Discussion

C. Masloch, 2023-08-13 20:21:04 +0000 Aug Sun

I prepared an Enhanced DR-DOS repo with all old history until 2011, as well as a few patches added by me now: https://www.bttr-software.de/forum/forum_entry.php?id=20555

I took the opportunity to create an EDR-DOS repo on our server, at https://hg.pushbx.org/ecm/edrdos (I interpret the new CP/M and derivatives license agreement as of 2022-07-07 as including EDR-DOS, so it should be fine to host it. This license agreement is in the file license.htm in the repo's root directory.)

I added one patch to COMMAND that was needed to build with OpenWatcom 1.9 (from a DOS host system, running in dosemu2) fixing a bug.

I fixed the redirector support for functions 7142h and 71A6h, both to support the dosemu2 extensions and to never crash on a redirector handle. (If the extensions are not supported, 7142h returns an error code of CY, ax=0001h and 71A6h an error code of CY, ax=7100h (like MSWindows).)

Further, I modified both the old-style function 42h and 7142h to work on device handles in the same way as MSWindows, allowing to seek as if the device was an empty file. I also changed it so function 71A6h returns CY, ax=7100h on a device handle.

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