Running on DR-DOS v7.03, the int 25h call zeroes di leading to a crash
here when di is expected to preserve the stack pointer. So push di twice
and pop it twice. The second pop always gets the saved sp, regardless of
whether int 21h or int 25h/26h are used.
Refer to https://github.com/SvarDOS/edrdos/issues/57#issuecomment-2119360035
Also checks that the total amount of clusters is possible
for the detected file system, erroring out otherwise.
Small FAT32 is displayed in the verbose output specifically.
This should be Enhanced DR-DOS compatible.
oemboot.asm contains an optimisation to save 2 bytes,
by using mov instead of a lea with bp evaluating to
a constant value. This was needed to fit the addition
for 256 spc support. It is otherwise unrelated.
The LBA detection patch offsets in SYS have also been
updated to match the changed boot.asm offsets.
The int86 function is used to call interrupt 21h
service 32h in the reset_drive function. This
function returns a pointer using the ds register.
ds will usually point into the DOS data segment
then (for our kernel). However, the compiler
assumed ds to be unchanged.
cast array using pointer to first element [newboot] instead of pointer to whole array [&newboot] to avoid OW error W115 "&array may not produce intended result" since the address of operator "&" is not required for getting the address of an array.
