The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

  • My badges

  • Twitter Updates

  • My Flickr Stream

  • Pages

  • All categories

  • Enter your email address to subscribe to this blog and receive notifications of new posts by email.

    Join 1,525 other followers

Archive for the ‘6502’ Category

6502 emulation: the ICE, or in-circuit-emulator…

Posted by jpluimers on 2019/02/05

On my list of hardware things to try:

[WayBack] a different take on 6502 emulation: the ICE, or in-circuit-emulator… – mos6502 – Google+

Basically it consists of three parts:

 

–jeroen

 

Posted in 6502, Development, Hardware Development, History, Z80 | Leave a Comment »

A refefernce to 6502 by “Remember that in a stack trace, the addresses are return addresses, not call addresses – The Old New Thing”

Posted by jpluimers on 2018/09/11

On x86/x64/ARM/…:

It’s where the function is going to return to, not where it came from.

And:

Bonus chatter: This reminds me of a quirk of the 6502 processor: When it pushed the return address onto the stack, it actually pushed the return address minus one. This is an artifact of the way the 6502 is implemented, but it results in the nice feature that the stack trace gives you the line number of the call instruction.

Of course, this is all hypothetical, because 6502 debuggers didn’t have fancy features like stack traces or line numbers.

Source: [WayBackRemember that in a stack trace, the addresses are return addresses, not call addresses – The Old New Thing

Which resulted in these comments at [WayBack] CC +mos6502 – Jeroen Wiert Pluimers – Google+:

  • mos6502: And don’t forget the crucial difference in PC on 6502 between RTS and RTI!
  • Jeroen Wiert Pluimers: +mos6502 I totally forgot about that one. Thanks for reminding me
    <<Note that unlike RTS, the return address on the stack is the actual address rather than the address-1.>>

References:

[WayBack6502.org: Tutorials and Aids – RTI

RTI retrieves the Processor Status Word (flags) and the Program Counter from the stack in that order (interrupts push the PC first and then the PSW).

Note that unlike RTS, the return address on the stack is the actual address rather than the address-1.

[WayBack6502.org: Tutorials and Aids – RTS

RTS pulls the top two bytes off the stack (low byte first) and transfers program control to that address+1. It is used, as expected, to exit a subroutine invoked via JSR which pushed the address-1.

RTS is frequently used to implement a jump table where addresses-1 are pushed onto the stack and accessed via RTS eg. to access the second of four routines.

–jeroen

Posted in 6502, 6502 Assembly, Assembly Language, Development, History, Software Development, The Old New Thing, Windows Development, x64, x86 | Leave a Comment »

Dennis1000/mos6502-delphi: A MOS 6502 CPU emulator written in Delphi (a very basic C64 + VIC20 emulator included)

Posted by jpluimers on 2018/06/25

Really cool history: [Archive.isDennis1000/mos6502-delphi: A MOS 6502 CPU emulator written in Delphi (a very basic C64 + VIC20 emulator included)

It should run on most 32-bit Delphi versions.

via:

–jeroen

Posted in 6502, C64, Commodore, Delphi, Development, History, Software Development, VIC-20 | 2 Comments »

Apple II Ethernet Module – a2RetroSystems

Posted by jpluimers on 2018/05/25

Reminder to self: see if I can order this:

Apple II Ethernet Module – This product is based on the Wiznet W5100 chip. It has an embedded hardware IP stack. Contiki, IP65, Marinetti and ADTPro have been updated to work with the new card.

We will be using Itead as our current PCB supplier.
The card will be assembled by Circuits Central

Source: [WayBackWelcome to a2RetroSystems

Other links:

–jeroen

Read the rest of this entry »

Posted in //e, 6502, Apple, Apple ][, History, Power User | Leave a Comment »

Open Apple #66 (December 2016) : Glenda “The Atom” Adams | Open Apple

Posted by jpluimers on 2018/05/21

From a while back: [WayBack] Open Apple #66 (December 2016) : Glenda “The Atom” Adams | Open Apple

This month on Open Apple, we sit down with Glenda Adams, better known on the Apple II as The Atom. She was a cracker of some note back in the 1980s, and she shares great stories with us…

It reminded me of the days I started to learn programming. Good memories. @glenda_atom was way ahead of me (:

–jeroen

Posted in //e, 6502, Apple, Apple ][, Classic Macintosh, History, Macintosh SE/30, Power User | Leave a Comment »

 
%d bloggers like this: