Early mid August work

2023-08-13

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

• 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

• 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

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.

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.

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