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Re: 6502 anyone ?

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On Thursday, April 13, 2017 at 8:02:17 PM UTC-7, HAA wrote:
> hughaguilar96@gmail.com wrote:
> > On Wednesday, April 12, 2017 at 5:43:35 PM UTC-7, HAA wrote:
> > > ...
> > > Keeping in mind it was intended to be a low-cost, bare-bones,
> > > alternative to the 6800 aimed at microcontroller work, the limited
> > > register set/size and missing instructions are understandable.
> > > The failure to correct existing broken instructions wasn't.
> > > ...
> > > You can blame Wozniak and the hobbyists for the appearance of
> > > the 6502 in systems for which it wasn't intended.  Tramiel and co.
> > > weren't going to complain.  They were making buckets of money
> > > riding the crest of a craze.
> >
> > The 65c02 was a disappointment. It could have been so much better! If the JMP indirect
> > instruction had used the Y register, the 65c02 would have been a very good processor
> > for VMs. You could have 128 primitives each with a one-byte code. Your generated code
> > would be quite compact. Most of the VM instructions would be one byte. Some of them
> > would be two or three bytes because they have an operand. The NEXT routine would be
> > very fast (note for Mark Wills: this NEXT would be about an order of magnitude faster
> > than anything that could be done on the Z80).
> > ...
> 
> Making the 6502 better would have entailed a total redesign.  The 6502 was built
> around small.  Lack of 16-bit regs, limited zero page and fixed stack all became
> problematic for larger apps.  Intel took the opposite approach when upgrading
> the 8008 to 8080.  The 8080 was well suited for writing an OS and apps such
> as language compilers.

Well, I'm not suggesting a total redesign. 

1.) Make the JMP indirect use Y rather than X.

2.) Make code and data reside in separate 64KB memories (with a 17-bit address bus).

3.) Get rid of the indirect,X addressing mode because it is almost never used.

Note that #3 would made the 6502 smaller --- this could free up some chip space to allow some new instructions --- a multiply would be hugely helpful!

BTW: Abrash's famous book has a chapter titled: "Strange Fruit of the 8080" --- describes how the 8080 affected the future x86 chips in weird ways.

Also, I don't think the 8080 was: 
"well suited for writing an OS and apps such as language compilers." 
CP/M wasn't all that great.

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6502 anyone ? john <anon@example.com> - 2017-04-11 13:07 +0100
  Re: 6502 anyone ? rickman <gnuarm@gmail.com> - 2017-04-11 23:31 -0400
    Re: 6502 anyone ? Mark Wills <markwills1970@gmail.com> - 2017-04-12 01:27 -0700
      Re: 6502 anyone ? Lars Brinkhoff <lars.spam@nocrew.org> - 2017-04-12 10:46 +0200
        Re: 6502 anyone ? Mark Wills <markwills1970@gmail.com> - 2017-04-12 01:57 -0700
          Re: 6502 anyone ? Lars Brinkhoff <lars.spam@nocrew.org> - 2017-04-12 12:24 +0200
          Re: 6502 anyone ? hughaguilar96@gmail.com - 2017-04-12 14:37 -0700
            Re: 6502 anyone ? lehs <skydda.barnen@gmail.com> - 2017-04-12 17:16 -0700
              Re: 6502 anyone ? hughaguilar96@gmail.com - 2017-04-12 18:10 -0700
                Re: 6502 anyone ? lehs <skydda.barnen@gmail.com> - 2017-04-12 23:46 -0700
                Re: 6502 anyone ? rickman <gnuarm@gmail.com> - 2017-04-13 03:00 -0400
                Re: 6502 anyone ? lehs <skydda.barnen@gmail.com> - 2017-04-13 00:37 -0700
                Re: 6502 anyone ? lehs <skydda.barnen@gmail.com> - 2017-04-13 00:42 -0700
                Re: 6502 anyone ? rickman <gnuarm@gmail.com> - 2017-04-13 12:57 -0400
                Re: 6502 anyone ? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-13 12:01 -0500
                Re: 6502 anyone ? lehs <skydda.barnen@gmail.com> - 2017-04-13 10:42 -0700
                Re: 6502 anyone ? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-13 12:55 -0500
                Re: 6502 anyone ? lehs <skydda.barnen@gmail.com> - 2017-04-13 11:13 -0700
                Re: 6502 anyone ? rickman <gnuarm@gmail.com> - 2017-04-13 14:24 -0400
                Re: 6502 anyone ? lehs <skydda.barnen@gmail.com> - 2017-04-13 11:57 -0700
                Re: 6502 anyone ? rickman <gnuarm@gmail.com> - 2017-04-13 15:15 -0400
                Re: 6502 anyone ? rickman <gnuarm@gmail.com> - 2017-04-13 14:23 -0400
        Re: 6502 anyone ? john <anon@example.com> - 2017-04-12 10:25 +0100
        Re: 6502 anyone ? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-04-12 12:27 +0200
          Re: 6502 anyone ? Lars Brinkhoff <lars.spam@nocrew.org> - 2017-04-12 12:53 +0200
            Re: 6502 anyone ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-12 12:55 +0000
              Re: 6502 anyone ? rickman <gnuarm@gmail.com> - 2017-04-12 12:20 -0400
          Re: 6502 anyone ? Mark Wills <markwills1970@gmail.com> - 2017-04-12 05:10 -0700
            Re: 6502 anyone ? Michael Barry <barrym95838@yahoo.com> - 2017-04-12 22:41 -0700
          Re: 6502 anyone ? Joel Rees <joel.rees@gmail.com> - 2017-04-13 02:14 -0700
            Re: 6502 anyone ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-13 11:01 +0000
              Re: 6502 anyone ? jim.brakefield@ieee.org - 2017-04-13 06:33 -0700
                Re: 6502 anyone ? Mark Wills <markwills1970@gmail.com> - 2017-04-13 07:24 -0700
                Re: 6502 anyone ? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-04-13 09:51 -0500
                Re: 6502 anyone ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-04-13 17:16 +0000
                Re: 6502 anyone ? hughaguilar96@gmail.com - 2017-04-13 13:08 -0700
              Re: 6502 anyone ? Joel Rees <joel.rees@gmail.com> - 2017-04-14 08:06 -0700
            Re: 6502 anyone ? rickman <gnuarm@gmail.com> - 2017-04-13 13:00 -0400
      Re: 6502 anyone ? "HAA" <someone@microsoft.com> - 2017-04-13 10:42 +1000
        Re: 6502 anyone ? hughaguilar96@gmail.com - 2017-04-12 18:45 -0700
          Re: 6502 anyone ? "HAA" <someone@microsoft.com> - 2017-04-14 13:01 +1000
            Re: 6502 anyone ? rickman <gnuarm@gmail.com> - 2017-04-14 01:21 -0400
            Re: 6502 anyone ? hughaguilar96@gmail.com - 2017-04-13 23:23 -0700
    Re: 6502 anyone ? john <anon@example.com> - 2017-04-12 10:08 +0100

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