MCL65: cycle accurate 6502 vhdl code?

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Newsdee
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MCL65: cycle accurate 6502 vhdl code?

Postby Newsdee » Tue Nov 28, 2017 4:04 am

This seems useful for many existing cores:
http://www.microcorelabs.com/mcl65.html

As far as I can tell, the license is compatible with MIST/MiSTer sources

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Re: MCL65: cycle accurate 6502 vhdl code?

Postby Sorgelig » Tue Nov 28, 2017 8:02 am

I think current 6502 is already good enough. At least it's not a weakest part of C64 core. Currently, chipset is the weakest part. When it will work as in original C64, then there will be time to check the 6502 model.
As for mcl65 itself, it's not a best model. Actually, it's based on state machine with 6502 microcode. Microcode is NOT open source, so it's the least desired module.
Strictly speaking is't not HDL code since the main logic is in microcode (and not opened for public).

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Re: MCL65: cycle accurate 6502 vhdl code?

Postby Newsdee » Tue Nov 28, 2017 2:32 pm

Sorgelig wrote:Strictly speaking is't not HDL code since the main logic is in microcode (and not opened for public).

Aha... I thought there was a catch :(

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Re: MCL65: cycle accurate 6502 vhdl code?

Postby bernouilli » Wed Nov 29, 2017 10:11 am

@Sorgelig : why do you write that the microcode isn't open to public ?
The sources contains the hdl source file that implements the "sequencer" (MCL65.v) and the code for the 6502 written in microcodes (both the "binary" and the disassembled code : microcode_rom.hex).
And in all the files there is the same copyright notice :
// Copyright (C) 2017 by Ted Fried info@MicroCoreLabs.com
//
// Permission to use, copy, modify, and distribute this software and its
// documentation for any purpose and without fee is hereby granted, provided
// that the above copyright notice appear in all copies and that both that
// copyright notice and this permission notice appear in supporting documentation.
// This software is provided "as is" without express or implied warranty.

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Re: MCL65: cycle accurate 6502 vhdl code?

Postby hoglet » Wed Nov 29, 2017 11:12 am

Newsdee wrote:
Sorgelig wrote:Strictly speaking is't not HDL code since the main logic is in microcode (and not opened for public).

Aha... I thought there was a catch :(

If you look inside the hex file, you'll see it is very well commented. I don't think there is any other source code.

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Re: MCL65: cycle accurate 6502 vhdl code?

Postby Sorgelig » Wed Nov 29, 2017 11:39 am

bernouilli wrote:The sources contains the hdl source file that implements the "sequencer" (MCL65.v) and the code for the 6502 written in microcodes (both the "binary" and the disassembled code : microcode_rom.hex).

Yeah, strange hex file. I didn't look inside because hex is usually just binary.
Anyway, current 6502 HDL model is good enough. C64 core requires a better chipset models.


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