Many fixes and improvements to the BIOS Extension ROM. (#33)

* Revert "Uploaded_2_9_2025"

This reverts commit ec79bbdbc9.

* Fixing DEBUG_IO builds.

* Make the IO port base a define.

* Fix CPU test to properly handle 808x vs V20.

* Improve timeout management logic.

* Improve SD Card initialization logic.

* Implement INT18h bootstrapping.

* Implementing a different test for processor type.

* Allow use with another fixed drive (eg: ESDI drive).

* Allow swapping driver ID between the BIOS disk and XTMax.

* Fix address of the ROM segment.

* Fixing missing STI at the top of the handler.

* Major rework of IO to use MOVSW.

* More code reorg and auto-detecting second drive.

* Update XTSD to use MOVSW.

* Add diagnostics program.

* Workaround for MS-DOS strange handling of interrupts.

* Use a lookup table for the memory map.

* Make the BootROM relocatable.

* Some more refactor of the Teensy code.

XTMax/Drivers/SDPP/MAKEFILE

@@ -5,7 +5,7 @@ ASM=tasm -mx
 
 DEPS=cprint.c driver.c sd.c sdmm.c cprint.h diskio.h driver.h integer.h sd.h standard.h 
 
-all: xtsd.sys xtsd186.sys
+all: xtsd.sys
 
 .asm.obj:
    $(ASM) $*
@@ -17,13 +17,6 @@ xtsd.sys: header.obj $(DEPS)
    $(CC) driver.c
    tlink -t -m -s -n header cprint sd sdmm driver, $@
 
-xtsd186.sys: header.obj $(DEPS)
-   $(CC) -1 -DUSE186 cprint.c
-   $(CC) -1 -DUSE186 sd.c
-   $(CC) -1 -DUSE186 sdmm.c
-   $(CC) -1 -DUSE186 driver.c
-   tlink -t -m -s -n header cprint sd sdmm driver, $@
-
 clean:
    del *.obj
    del *.map