I'm on fully up to date gentoo using openjdk and the top options File, View, Simulator don't work. When i try to click them there only open while I'm clicking and i can't click anything in it

I followed the instructions for getting EhBASIC working and after a while noticed that nothing seemed to be working. I then looked at the memory map and everything was blank.

• copy ehbasic.rom to same folder as .jar; renaming it to rom.bin.
• double click on .jar (on Windows 11 if that matters)...

Memory blocks are empty, no error message, no indication that anything was loaded.

I then attempted to start the .jar using command line java -jar symon-1.3.2.jar and got the following error:

[main] INFO com.loomcom.symon.machines.SymonMachine - No ROM file specified, loading empty R/W memory image

Starting it by appending -rom rom.bin... things working as expected.

(BTW, THANK YOU!!!! I've spent the past several hours trying to get a copy of EhBASIC up and running so I can experiment with it for https://gotbasic.com and thanks to your efforts, SUCCESS!)

% mvn package
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 8.373 s
[INFO] Finished at: 2021-09-25T06:51:32+01:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-jar-plugin:2.6:jar (default-jar) on project symon: Execution default-jar of goal org.apache.maven.plugins:maven-jar-plugin:2.6:jar failed: An API incompatibility was encountered while executing org.apache.maven.plugins:maven-jar-plugin:2.6:jar: java.lang.ExceptionInInitializerError: null

% mvn -v
Apache Maven 3.8.2 (ea98e05a04480131370aa0c110b8c54cf726c06f)
Maven home: /usr/local/Cellar/maven/3.8.2/libexec
Java version: 17, vendor: Homebrew, runtime: /usr/local/Cellar/openjdk/17/libexec/openjdk.jdk/Contents/Home
Default locale: en_GB, platform encoding: UTF-8
OS name: "mac os x", version: "10.15.7", arch: "x86_64", family: "mac"

Hello again!

BBC BASIC processes a command by calling BRK after typing a command and pressing enter.

This means that by default, Symon halts every time I send a new command. At every start, I have to disable it manually in the settings.

What would make things quicker and easier for me is a command line flag (perhaps "--no-halt" / "-nh"?) that would disable the halt on break at the very start.

Hello!

I've run into an issue while trying to use the serial terminal with the ACIA 6551 emulator. Transmitting the delete character (0x7F) successfully deletes the last character sent, but seems the backspace character (0x08) doesn't do the same. It just makes an empty space. I don't have the same problem on real hardware.

Is that by design, or is it an issue? It may be a problem with my own code, so let me know if you can't replicate it.

Hello,

I was searching for a 6502 tool to try to debug understand an old pcb poker game machine.

Sadly I give up on your prog. Strictly zero interest in installing or building any java things (mvn ????).

I just need "java -jar 6502emu.jar" !!!!!

Just publish the jar file.

Thank you

First of all, thanks for making Symon! For someone just getting into 6502 programming, it's great to have a 6502 emulator with a simple memory map, simple I/O devices, that just loads a ROM my assembler toolchain produces.

I have noticed one puzzling behaviour, however, with the CRTC output.

Let's say I have the following program:

; Draw 'A' at the top-left position
lda #$41
sta $7000

I assemble it, I run java -jar symon-1.3.2.jar -rom symon-demo.rom, I enable the Video Window from the View menu, then I hit Run. In the top left corner of the Video window, underneath the blinking cursor, I get a capital A as expected. But that blinking cursor is distracting, let's try turning it off:

 ; select CRTC register 10, Cursor Start/Blink
lda #$0A
sta $9000
; Leave the start scanline at 0, set the blink mode to 01, hide cursor
lda #$10
sta $9000

; Draw 'A' at the top-left position
lda #$41
sta $7000

Now when I assemble and run the ROM, the Video window just stops updating: the cursor stops blinking, the top left position never changes to A. If I close the Video window and then re-open it, it correctly shows the new state.

Possibly related: if I click "Hard Reset" in the UI, the cursor does not resume blinking, even if I close and re-open the window.

Can you provide the steps necessary to get EhBASIC loaded/running? I see a screen shot in the main README showing that 2.22 is being utilized; are these from http://retro.hansotten.nl/uploads/leedavison/6502_EhBASIC_V2.22-master.zip and is it the regular or patched version? If not, where would I find a copy of this?

Any assistance with this would be wonderful and, assuming can get it working, I will be sure to include these instructions (and link to this project) on https://gotbasic.com under the EhBASIC section.

Thanks in advance.

I am asking around since this looks pretty cool. would there be any way to implement this as a library in eg: a minecraft mod to bring back the glory of redpower2

I think it's a great idea for somebody learning assembly programming to be able to use actual real-world data-sheets for reference, and get a feel for what low-level programming is actually like. On the other hand, the whole reason we want to use an emulator to begin with is because real-world hardware is awkward and inconvenient in many ways, so there are good reasons to not implement every quirk of some piece of hardware. However, if the implemented hardware differs from the behaviour described in the data-sheet, it's good to document that so that people know what to expect.

This issue is about deciding how much actual 6551 behaviour Symon should implement, and then making sure that behaviour is implemented, and the remaining differences are documented.

I've been tinkering with Symon's emulated 6551, examining data-sheets and sample code I found online to figure out how it worked and what was going on. The first issue is that there are several data-sheets online for 6551-related chips, and it wasn't clear which one Symon was trying to match:

• The original MOS 6551
• The WDC W65C51S
• The WDC W65C51N

The original MOS 6551 data-sheet specifies (on page 7) that the power-on state of the the Command register is $02, i.e. with the receiver interrupt disabled. The power-on state of the Command register in Symon is $00, so it can't be emulating an original MOS 6551.

The W65C51N data-sheet documents (on page 9) that due to a design fault, the "Transmitter Data Register Empty" bit in the status register is broken and can't be relied upon, and that seems the kind of behaviour that's more annoying than educational, so I think Symon shoudn't emulate the W65C51N.

By elimination, that means Symon emulates the W65C51S.

Comparing Symon's behaviour to the W65C51S data-sheet, I note the following discrepancies:

• The ACIA exposes the state of the "Data Carrier Detect" and "Data Set Ready" serial-port pins in the status register, and it is supposed to generate an interrupt when either one changes state. However, in Symon the ACIA is permanently wired to the VT100 terminal in the main window, so it is impossible for them to change state
• Wikipedia tells me that for half-duplex communication the local computer should activate the "Ready To Send" pin, and wait for the "Clear To Send" pin to be raised by the remote side before sending. For full-duplex communication, the local computer is assumed to always be ready to send, and the RTS pin means "ready to receive" instead. There are bits in the ACIA command register to activate or deactivate the RTS pin, but both sending and receiving work just fine when it's inactive.
• The ACIA has an internal clock generator that can be configured to a number of different baud-rates, or it can be configured to use an external clock. Symon does not mention that it implements an external clock, so I worried that configuring the ACIA to use it might prevent anything from being transmitted. However, "external clock" mode is special-cased to mean "as fast as possible"
• The ACIA can be configured to send a different number of bits per character. However, Symon always sends 8 bits.
• There's a bit in the Command register that controls the "Data Terminal Ready" serial-port pin. The W65C51S data-sheet documents (on page 12) that it "enables all selected interrupts". The MOS 6551 data-sheet describes that flag as "enable receiver/transmitter". It seems like this should be a master switch for the entire ACIA, but in Symon everything works perfectly regardless of the state of this bit.
• Although bit 1 of the Command register defaults to 0 ("rx interrupts enabled"), the ACIA's power-on state is "rx interrupts disabled", which means the should-be-noop instructions lda $8802; sta $8802 actually result in rx interrupts being enabled

[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.167 s
[INFO] Finished at: 2021-09-10T02:39:45+01:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.12.4:test (default-test) on project symon: There are test failures.
[ERROR]
[ERROR] Please refer to /Users/graeme/Downloads/symon-master/target/surefire-reports for the individual test results.
[ERROR] -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException

first exception is
changeCursorStartLineShouldTriggerCallback(com.loomcom.symon.CrtcTest)

% ls -la which mvn
lrwxr-xr-x 1 gharker admin 29 10 Sep 02:24 /usr/local/bin/mvn -> ../Cellar/maven/3.8.2/bin/mvn

% mvn -v
Apache Maven 3.8.2 (ea98e05a04480131370aa0c110b8c54cf726c06f)
Maven home: /usr/local/Cellar/maven/3.8.2/libexec
Java version: 16.0.2, vendor: Homebrew, runtime: /usr/local/Cellar/openjdk/16.0.2/libexec/openjdk.jdk/Contents/Home
Default locale: en_GB, platform encoding: UTF-8
OS name: "mac os x", version: "10.15.7", arch: "x86_64", family: "mac"
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