Rascherite's z80 ASM Question Thread

Rascherite · Posted: 06 Jan 2012 01:58:46 pm Post subject:

haha yeah, I need to get out of that double-posting habit. glad I found the delete post button.

So, is the actual doorscs more like my routine? Is doors CS open source?
_________________
"If you don't live it, it won't come out of your horn."
-Charlie Parker

TI BASIC Sudoku - optimizing random puzzle generator, making number of preset squares more even and reliable

asm metronome - trying to figure out how to dougie with the interrupts

KermMartian · Posted: 06 Jan 2012 02:01:08 pm Post subject:

Rascherite · Posted: 06 Jan 2012 02:03:53 pm Post subject:

KermMartian · Posted: 06 Jan 2012 02:12:54 pm Post subject:

That's correct. The way it works out, it's just as fast as having separate routines for those special cases, and saves the memory of needing to have code for the special cases. Doors CS is closed-source, although if people ask nicely and I trust them as individuals to not re-use or re-distribute my code without asking, I generally give pieces of my code to people.
_________________

Rascherite · Posted: 06 Jan 2012 02:17:15 pm Post subject:

KermMartian · Posted: 06 Jan 2012 02:29:13 pm Post subject:

There are a few; the most impressive is the IDA Pro disassembler that BrandonW recommends. Also, my policy on open-sourcing calculator code comes from a few rather significant incidents in which members of the community blatantly stole and used code I had released under a limited license without proper attribution, then claimed it was OK to violate my license. That sort of behavior makes me very angry, not that I think you would ever do something like that.
_________________

Rascherite · Posted: 06 Jan 2012 02:41:35 pm Post subject:

Ashbad · Posted: 06 Jan 2012 02:48:24 pm Post subject:

Interrupts are triggered in many ways, depending on the IM (Interrupt Mode). IM 0 is unusable on the 84+, since it requires sending an instruction on the data bus (and we cannot do that) such as RST 38h, RST 8h, etc. IM 1 will jump to address 0x0038 on each call, and is triggered by peripheral devices usually. IM 2 is what you usually use, and involves using a vector table, working with the I register, etc. (It's a bit more to explain, so looking at something like brandonw's wiki should say enough about it).
_________________
-Ashbad

Rascherite · Posted: 06 Jan 2012 02:58:53 pm Post subject:

Thanks, ashbad! Can you maybe link me up to the page?

Random question about code appearance... Is it more common to have tabs or spaces between instructions and operands?

KermMartian · Posted: 06 Jan 2012 03:04:47 pm Post subject:

It's more common in community code to use a space. TI code almost always uses a tab in between, and frequently uppercase registers and opcodes.
_________________

Rascherite · Posted: 06 Jan 2012 06:29:26 pm Post subject:

<badjoke>I guess ti just knows that CAPSLOCK IS CRUISE CONTROL FOR COOL</badjoke>

Seriously, though, I can't stand it when register names and opcodes are in all caps. Its so annoying.
_________________
"If you don't live it, it won't come out of your horn."
-Charlie Parker

TI BASIC Sudoku - optimizing random puzzle generator, making number of preset squares more even and reliable

asm metronome - trying to figure out how to dougie with the interrupts

KermMartian · Posted: 06 Jan 2012 09:09:59 pm Post subject:

Ashbad · Posted: 06 Jan 2012 09:38:02 pm Post subject:

As for a link, http://z80-heaven.wikidot.com/interrupts seems to be a very good generalization of basically everything you'll need to know about interrupts on the 84+. Any questions beyond that, Kerm is definitely your man.
_________________
-Ashbad

Rascherite · Posted: 08 Jan 2012 02:26:42 am Post subject:

If you're writing a subroutine that will be used over and over, e.g, a line drawer, is it bad practice to reserve 3 or 4 bytes of ram for it, or should you use only the registers and the stack?

like, is this acceptable?

quigibo · Posted: 08 Jan 2012 04:17:03 am Post subject:

That's generally acceptable if you absolutely have to, but keep in mind it will prevent the following things:

- Recursion won't work.
- You can't call the routine from an interrupt if you use it elsewhere.

KermMartian · Posted: 08 Jan 2012 01:22:24 pm Post subject:

Rascherite · Posted: 08 Jan 2012 08:50:24 pm Post subject:

What is saferam?
_________________
"If you don't live it, it won't come out of your horn."
-Charlie Parker

TI BASIC Sudoku - optimizing random puzzle generator, making number of preset squares more even and reliable

asm metronome - trying to figure out how to dougie with the interrupts

willrandship · Posted: 08 Jan 2012 08:51:26 pm Post subject:

Saferam in axe can be easily accessed with L1 through L6 (they're in the Command list with descriptions on just how safe they really are)

Basically it's ram outside your program that can be used for temporary storage
_________________
Hmm...what to put here....

Ashbad · Posted: 08 Jan 2012 08:52:00 pm Post subject:

Rascherite · Posted: 08 Jan 2012 08:52:40 pm Post subject:

I'm not using axe... and I also want to know WHAT it is, HOW it is different from normal RAM, and WHY it can be used for subroutines.

edit: