Hi all
Wonder if someone can offer some advice? I'm trying to get my program to load
in new data during runtime. I can do this at the start of the program by
pointing IX to my uifa, loading the header and then pointing IX to the difa and
c,d and e to the appropriate place as per the technical manual (although it
states the difa is returned 80bytes above my uifa which isn't the case - it
seems to be at &4b50 as per the documentation for B-Dos (but I'm not using
b-dos, I'm using Samdos (or so I thought!))). Example code that I am using (and
works fine when called the machine code from the basic prompt):
ld ix,uifa
RST &08
DEFB 129
ld ix,&4B50
ld c,(ix+34)
ld e,(ix+35)
ld d,(ix+36)
ld hl,&8000
rst &08
defb 130
uifa: defm 19,'level1.bin'
So that works ok, I can load about 15 files in to whatever pages I need and all
is well until I then want to load in a bunch more later. I assumed it would be
a simple case of paging the ROM back in and running the same code as above only
it crashes when I try to read in the header of the file. Am I missing something
really obvious that I need to do after I page the ROM in and before I run the
code to load the file? I thought it might be the stack pointing to a random
location but even after re-pointing to what appears to be a clean place in free
memory it still goes haywire
Any tips?
Cheers!
