Synassembler monitor crash

[archon800]

I'm working on a program that reads paddle A and displays the value as a decimal number. It's a little buggy. Sometimes it displays a ":" instead of a digit. So I'm trying to figure it out with Synassembler's built in monitor (Zynapse monitor). When tracing or stepping through, it locks up the system - black screen, unresponsive - at line 280 (it's a DEX). I'm using Altirra and I've tried a couple different OS ROMs, switching PAL/NTSC, different RAM configuration, different Synassembler executables, and different versions of Altirra. Is Synapse's monitor just buggy and can't do it? What's going on?

Paddle to decimal.atr

[phaeron]

First, this is the problem in your program:

00460          LSR  ;NYBBLE
00470          ADC #$10 ; CONVERT TO ATASCII

You have a stray carry from bit 3 into the ADC operation here. Either insert a CLC before the ADC or use ORA #$10 instead.

 

As for why the Synassembler monitor crashes, it has a bug with leaving the decimal flag on when emulating branches:

  27008:231:  3 | A=04 X=00 Y=00 (    ZC) | B854: B1 D8             LDA ($D8),Y  ;$401D
  27008:231:  8 | A=D0 X=00 Y=00 (N    C) | B856: 99 B2 00          STA $00B2,Y  ;$00B2
  27008:231: 13 | A=D0 X=00 Y=00 (N    C) | B859: 88                DEY
  27008:231: 15 | A=D0 X=00 Y=FF (N    C) | B85A: 10 F8             BPL $B854
- 27008:231: 17 | A=D0 X=00 Y=FF (N    C) | B85C: 20 B3 BA          JSR $BAB3
    27008:231: 23 | A=D0 X=00 Y=FF (N    C) | BAB3: A5 BE             LDA $BE
    27008:231: 27 | A=38 X=00 Y=FF (     C) | BAB5: 48                PHA
    27008:231: 31 | A=38 X=00 Y=FF (     C) | BAB6: A5 BB             LDA $BB
    27008:231: 35 | A=00 X=00 Y=FF (    ZC) | BAB8: A6 BC             LDX $BC
    27008:231: 39 | A=00 X=07 Y=FF (     C) | BABA: A4 BD             LDY $BD
    27008:231: 43 | A=00 X=07 Y=00 (    ZC) | BABC: 28                PLP
    27008:231: 48 | A=00 X=07 Y=00 (  D   ) | BABD: 58                CLI
    27008:231: 51 | A=00 X=07 Y=00 (  D   ) | BABE: 60                RTS
  27008:231: 59 | A=00 X=07 Y=00 (  D   ) | B85F: 4C B2 00          JMP $00B2
  27008:231: 62 | A=00 X=07 Y=00 (  D   ) | 00B2: D0 04             BNE $00B8
  27008:231: 65 | A=00 X=07 Y=00 (  D   ) | 00B8: 4C F0 B8          JMP $B8F0
  27008:231: 68 | A=00 X=07 Y=00 (  D   ) | B8F0: 18                CLC
  27008:231: 70 | A=00 X=07 Y=00 (  D   ) | B8F1: A0 01             LDY #$01
  27008:231: 72 | A=00 X=07 Y=01 (  D   ) | B8F3: B1 D8             LDA ($D8),Y  ;$401E

The monitor then tries to print text to the Screen Editor (E:) device, which dies horribly with decimal mode on because its address calculations are all wrong.

 

[archon800]

First, this is the problem in your program:

 

00460          LSR  ;NYBBLE
00470          ADC #$10 ; CONVERT TO ATASCII

You have a stray carry from bit 3 into the ADC operation here. Either insert a CLC before the ADC or use ORA #$10 instead.

 

 

Hey, it works. Thanks!

 

Would I be better off using another monitor? One of the OS replacements like Omnimon?

[phaeron]

You could try a different monitor, but the emulator you are using has a machine language debugger built in. (Disclaimer: I wrote it.)

[Heaven/TQA]

And it's one of the best... I even use less frequently the "A8" command

[archon800]

You could try a different monitor, but the emulator you are using has a machine language debugger built in. (Disclaimer: I wrote it.)

 

Yes, I know. I want to be able to do this on real hardware though.