Groups > comp.sys.apple2.programmer > #2665

PLASMA/Acme oddity

Newsgroups	comp.sys.apple2.programmer
Date	2016-04-06 11:28 -0700
Message-ID	<6f438e11-3d4b-413c-afe1-e199203ba480@googlegroups.com> (permalink)
Subject	PLASMA/Acme oddity
From	mike.finger@gmail.com

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I have a question related to PLASMA and, by extension, the ACME assembler.

The issue I'm running into is that I have some inline assembly in a function in PLASMA that is using labels.

I trying to put in the No-Slot Clock time routines I borrowed from the ADTPro source. I converted it to work with ACME, but it seems to be computing absolute label offsets based on the passed in program counter and not by location within the assembly code.

Here is an example (PLASMA):
asm _gettime
L0260 lda #$00
sta L02DE
lda #$03
L0267 ora #$C0
sta L031F
L026C sta L0322
sta L0331
sta L033F
lda #$03
sta L02DF
one L0292
...
L02DE brk
L02DF brk
L02E0 brk

When I compile it and load it up in PLASMA, I have the PLASMA code print out the address of _gettime, which spits out $4047 as the address of _gettime

Looking at the in memory code I see this:
4047- A9 00 LDA #$00
4049- 8D B2 10 STA $10B2
404C- A9 03 LDA #$03
4067- 09 C0 ORA #$C0
4069- 8D F3 10 STA $10F3
406C- 8D F6 10 STA $10F6
406F- 8D 05 11 STA $1105
4072- 8D 13 11 STA $1113
4075- A9 03 LDA #$03
4077- 8D B3 10 STA $10B3
407A- D0 16 BNE $4079

The STA on 4049 should be $40C5 but it's $10B2, same with the other absolute address labels. 407A is correct, but that is a relative address.

It looks like offset that are too large for a relative offset are based on the current value of the PC.

I can get the offsets to be right if I run ACME with --setpc 16401 but then the execution crashes even before outputting the address value. Which I'd expect since I'm sure It messes up the entry point.

The loaded code runs correct (well, doesn't crash) if I do it from the monitor after it crashes:

*4047g
*

Has anyone run into this? Am I doing something wrong?

FWIW, I did originally load code found in here for NSC time byte for byte (via memcpy) to $260 and it runs fine, except PLASMA uses the zero page for things so we end up walking on each other.

Thanks for any help!

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PLASMA/Acme oddity mike.finger@gmail.com - 2016-04-06 11:28 -0700
  Re: PLASMA/Acme oddity David Schmenk <dschmenk@gmail.com> - 2016-04-07 08:42 -0700
    Re: PLASMA/Acme oddity David Schmenk <dschmenk@gmail.com> - 2016-04-07 08:51 -0700
      Re: PLASMA/Acme oddity Michael Finger <mike.finger@gmail.com> - 2016-04-07 09:29 -0700
        Re: PLASMA/Acme oddity David Schmenk <dschmenk@gmail.com> - 2016-04-07 11:17 -0700
          Re: PLASMA/Acme oddity Michael Finger <mike.finger@gmail.com> - 2016-04-08 11:13 -0700
            Re: PLASMA/Acme oddity Michael Finger <mike.finger@gmail.com> - 2016-04-08 11:14 -0700
            Re: PLASMA/Acme oddity David Schmenk <dschmenk@gmail.com> - 2016-04-08 13:19 -0700
              Re: PLASMA/Acme oddity Michael Finger <mike.finger@gmail.com> - 2016-04-08 21:45 -0700
                Re: PLASMA/Acme oddity David Schmenk <dschmenk@gmail.com> - 2016-04-09 08:56 -0700
                Re: PLASMA/Acme oddity David Schmenk <dschmenk@gmail.com> - 2016-04-09 09:14 -0700
                Re: PLASMA/Acme oddity Michael Finger <mike.finger@gmail.com> - 2016-04-09 11:52 -0700
                Re: PLASMA/Acme oddity D Finnigan <dog_cow@macgui.com> - 2016-04-09 20:09 +0000
                Re: PLASMA/Acme oddity Michael Finger <mike.finger@gmail.com> - 2016-04-11 08:42 -0700

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