6502.org

Posted: **Sun Dec 14, 2025 10:50 am**

Hey,

W.D.C. Tools https://wdc65xx.com/WDCTools includes WDCDB - program is a simulator/debugger for the W65C816S microprocessor .

In the menu Edit - Edit Startup Options - there is a setting: CPU Type.

: CPU_Type.png (858 Bytes) Viewed 696 times

If 65C816 is selected, the main registers like "A:" are shown in the registers view as 8-bit.

: view_regs.png (5.63 KiB) Viewed 696 times

And when in the configuration - e.g., the WDCDB.ini file in the [Setup] section,

Code: Select all

Target=6502

then the registers are 16-bit.

: view-regs.png (4.58 KiB) Viewed 697 times

Can anyone confirm this anomaly?

Posted: **Thu Dec 18, 2025 3:06 pm**

viewtopic.php?f=2&t=7500

I do.

If you run some code, you'll see the emulator works fine. The internal values of the registers are OK, but the visualization is wrong. I tried some creative ways to fix it by reverse engineering the software, but it way beyond my capabilities.

Posted: **Thu Dec 18, 2025 3:44 pm**

daniMolina wrote:

http://forum.6502.org/viewtopic.php?f=2&t=7500

I do.

If you run some code, you'll see the emulator works fine. The internal values of the registers are OK, but the visualization is wrong. I tried some creative ways to fix it by reverse engineering the software, but it way beyond my capabilities.

Many 65C816 native-mode simulators like this one are internally correct but display things in awkward or even incorrect ways. Even with detailed knowledge and experience with the 816, it’s not easy to get things right—behavior is much more complicated than with the 65C02.

Incidentally, the Kowalski assembler/simulator has a little bit of the same problem, since it is trying to be correct for both the eight-bit MPUs and the 816 when operating in either mode.

Posted: **Thu Dec 18, 2025 7:13 pm**

Thanks for the response.

I didn't find it earlier
viewtopic.php?f=2&t=7500
because I was looking (Emulation and Simulation) for: "WDCDB" & w65c02sxb

I just started browsing the forum.

Posted: **Thu Dec 18, 2025 10:48 pm**

(Welcome!)

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