This is part of a bigger project to emulate an NES (Nintendo Entertainment System).

NES uses R2A03 CPU designed by Ricoh, however this uses the circuit for 6502 CPU with just a few differences:

• No differences were found in the instruction decoder
• Flag D works as expected, it can be set or reset by CLD/SED instructions; it is used in the normal way during interrupt processing (saved on stack) and after execution of PHP/PLP, RTI instructions.
• Random logic, responsible for generating the two control lines DAA (decimal addition adjust) and DSA (decimal subtraction adjust) works normally.

https://forums.nesdev.org/viewtopic.php?t=9813

Start project in Vivado

1. Clone repository

git clone https://github.com/Danielvagyok/emulator_6502.git
cd emulator_6502

2. (Optional) Set alias for Vivado
   

   • Linux:

   echo "alias vivado=\"path/to/Xilinx/Vivado/2024.1/bin/vivado\"" >> ~/.bashrc
   source ~/.bashrc

   • Windows:

   echo "Set-Alias -Name vivado -Value path\to\Xilinx\Vivado\2024.1\bin\vivado" >> $profile
   . $profile

     Note 1: If $profile file does not exist, create it

   New-Item -Force -Path $profile

     Note 2: If scripts cannot be executed on your system, then open PowerShell in Administrator mode and change Execution Policy

   set-executionpolicy remotesigned

3. Build with Tcl script

vivado -source rebuild.tcl

Better description and Copyright for the project is soon to come.