If you don't particularly care about the state of regis

I'm kinda embarrassed but I can't figure out how to reset z
I've tried:
res  z
res  z,0
res  f,(somenumber)

And Spasm errored each time.
What am I doing wrong?

Is there a list of commands and BCALLs with what they affect? That would be really nice when programming.

Flags don't (re)set that way. They're often used to indicate additional effects of a prior operation (such as the particulars of an ADD or SUB operation, or a rotate/shift) but only the carry flag gets special treatment with "scf" and "ccf" instructions.

So in short, no there's no way to directly (and efficiently!) manipulate any flag other than the carry flag. To answer your question, however...

If you don't particularly care about efficiency, you can set the flags register to whatever you want by directly "loading" to it. This destroys all flags, register A, and whatever high byte of a pair you want to push. This uses 21+7 ccs at minimum on a z80:
ld c,%01000000 ;sets bits to load to the flags register
push bc
pop afYou can take a look at this page to learn the bit positions of the other flags in case you want to modify them too.

Now... if you don't particularly care about the contents of register A or the other flags you can do this to reset z:
SCF      ;Set carry flag
SBC A,A  ;A-A-1 = $FF. NZ.Or the following code to set it:
OR A     ;Reset carry flag
SBC A,A  ;A-A-0 = $00. ZBoth of the above solutions use 8 ccs on a z80.

As a note (and important if you're exploring other ways to try to mess with just Z), typical shift/rotate instructions (RLC C, RR L, SRL A) will affect Z like you'd think, but their more efficient single-byte version for register A (RLA, RRA, RLCA, etc.) does NOT. Had to learn that the hard way

EDIT: I lied. The bit that started with SCF was to reset, and the one with OR A was to set (post changed to reflect that). Heh. I confuse my thoughts and wording despite the comments themselves being correct.

Here is a good list of instructions: http://clrhome.org/table/
(As well as what they do, how many memory they take up, how long they take to execute, and more )

Thanks!
Is there any way to combine two files that fit in ram individually, but together can't? I have 2 very large text files, and can't find a way to combine them.

You can combine them with a computer-side editor, as you don't have a RAM limitation there. The only limitation you'll still have is that it has to fit in a ROM sector, which means it can be at most about 65500 bytes.

Perhaps the boot code flash test may help by either revealing a problem or magically fixing one? Also, have you tried sending other OS files, even different versions? Perhaps the one you have is somehow invalid?

Beyond that, I'd wait a bit for the replies of those more knowledgeable about the boot code and hardware, but you may be approaching panic level 6.