Cool! I didn't knew of your work. I've been working in the service table, just that it isn't ready yet because I want DS to handle filenames and ES the buffer but currently the segment mangling still is destroying the directory. Almost ready ;)
Code size suffered because the need to sanitize the ES register to access the directories (PUSH CS + POP ES) but balanced because I made bootOS to call its own services (3-byte CALL is now 2-byte INT) and fortunately IRET is same size as RET. The most difficult thing was to return the carry flag, but the RCL instruction saved me, I'm glad the 8088 processor auto-uses SS when using BP addressing. At some point I was closer to write in paper the segment dependancies along code paths because it's pretty hard to track. Timing I think isn't so important at this moment.
Haha this is one of the reasons I stuck with the simple jump table :) I will have to check whether I have enough space left to implement interrupts though, hopefully because I already do so many internal calls I will save bytes by reducing from a 3 byte call to a 2 byte interrupt.
