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The RTF65002 Core

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Rob Finch

Post subject: Re: The RTF65002 Core

Posted: Fri Apr 04, 2014 4:44 am

Joined: Sun Dec 29, 2002 8:56 pm
Posts: 460
Location: Canada

The RTF65002 core has been updated to add 65c816 backwards compatibility. It's currently untested, but synthesizes. The core size increased by about 20% and slowed down to 40MHz.
Code is on Github.

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BigEd

Post subject: Re: The RTF65002 Core

Posted: Fri Apr 04, 2014 9:22 am

Joined: Thu Dec 11, 2008 1:28 pm
Posts: 10985
Location: England

Wow, nice work - could this be the first HDL core with '816 operation?
Here's the link: https://github.com/robfinch/Cores/tree/ ... 5002/trunk
What's the license Rob?
Cheers
Ed

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ElEctric_EyE

Post subject: Re: The RTF65002 Core

Posted: Fri Apr 04, 2014 10:33 am

Joined: Mon Mar 02, 2009 7:27 pm
Posts: 3258
Location: NC, USA

BigEd wrote:

Wow, nice work - could this be the first HDL core with '816 operation?...
Cheers
Ed

The T65 cpu has limited 65C816 compatibility. Not sure how limited though... Good job Rob!

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Rob Finch

Post subject: Re: The RTF65002 Core

Posted: Sun Apr 06, 2014 7:49 am

Joined: Sun Dec 29, 2002 8:56 pm
Posts: 460
Location: Canada

BigEd wrote:

What's the license Rob?

The license is currently LGPL.

I've found and fixed several bugs in the core over the last couple of days. The '02 and 32 bit modes seem to work still as I can run my test system, but I really need some '816 code for testing.

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BigEd

Post subject: Re: The RTF65002 Core

Posted: Sun Apr 06, 2014 9:44 am

Joined: Thu Dec 11, 2008 1:28 pm
Posts: 10985
Location: England

> LGPL
Great - thanks!

Here's a short 65816 program:
viewtopic.php?p=15531#p15531
It might not be terribly suitable as a test...

Here's a pointer to a C compiler: viewtopic.php?p=8321#p8321

I wonder if rigging up an Apple IIGS type environment would be useful, and then running the ROMs for that machine, as a test?

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Rob Finch

Post subject: Re: The RTF65002 Core

Posted: Mon Apr 07, 2014 7:37 pm

Joined: Sun Dec 29, 2002 8:56 pm
Posts: 460
Location: Canada

BigEd wrote:

Here's a short 65816 program:
viewtopic.php?p=15531#p15531
It might not be terribly suitable as a test...

I got it to work as spec'd I think. It displayed 359 zeros on the screen

Methinks there is a software bug.
I managed to fix several "hardware" bugs while trying to run this program.

BigEd wrote:

I wonder if rigging up an Apple IIGS type environment would be useful, and then running the ROMs for that machine, as a test?

I think this would be quite an undertaking, but it might be about the best way to test. Likely at least have to mod the keyboard/mouse code to use a PC style interfaces. Got to wondering what a bare-bones GS system would look like.

I have an real IIe sitting at home with an 65C802 cpu in it.

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BigEd

Post subject: Re: The RTF65002 Core

Posted: Mon Apr 07, 2014 7:53 pm

Joined: Thu Dec 11, 2008 1:28 pm
Posts: 10985
Location: England

(It should print the digits of pi - 314 zeros would be forgivable, or even 360, but preferably the first digit should be 3.)

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Rob Finch

Post subject: Re: The RTF65002 Core

Posted: Tue Apr 08, 2014 9:09 am

Joined: Sun Dec 29, 2002 8:56 pm
Posts: 460
Location: Canada

I haven't figured it out yet. There must be an instruction that's failing. When I dump the P array it's all zeros. So candidates are a store that stores zero, (sta P-1,x) or perhaps a shift/rotates fails when doing multiplication or division. It's slow going debugging at the moment because it take 1 1/2 hours place and route. It does seem to iterate properly.

I repost the PI calc code in case I copied it wrong somewhere.

Code:

P   EQU      2
Q   EQU      1193*2 + 2
R   EQU      Q + 2
SSS   EQU      R + 2

Code:

Test816:
      clc
      xce
      cpu      W65C816S
      rep      #$30      ; acc,ndx = 16 bit
      mem      16
      ndx      16

      lda      #$1800      ; setup stack pointer
      tas

      jsr      INITSUB
      ldx      #359
      ldy      #1193
L1S:   
      phy
      pha
      phx
      stz      Q
;      txa
;      ldx      #5
;      wdm
;      xce
;      cpu      RTF65002
;      jsr      PRTNUM
;      clc
;      xce
;      cpu      W65C816S
;      rep      #$30
;      plx
;      phx
      tya
      tax
L2S:   
      txa
      jsr      MULSUB
      sta      SSS
      lda      #10
      sta      Q
      jsr      ADJ1SUB
      lda      P-1,x
      jsr      UNADJ1SUB
      jsr      MULSUB
      clc
      adc      SSS
      sta      Q
      txa
      asl
      dea
      jsr      DIVSUB
      jsr      ADJ1SUB
      sta      P-1,x
      jsr      UNADJ1SUB
      dex
      bne      L2S
      lda      #10
      jsr      DIVSUB
      sta      P
      plx
      pla
      ldy      Q
      cpy      #10
      bcc      L3S
      ldy      #0
      ina
L3S:   
      cpx      #358
      bcc      L4S
      bne      L5S
      jsr      OUTPUTSUB
      lda      #46
L4S:   
      jsr      OUTPUTSUB
L5S:   
      tya
      eor      #48
      ply
      cpx      #358
      bcs      L6S
      dey
      dey
      dey
L6S:   
      dex
      beq      L7S
      jmp      L1S
L7S:
      jsr      OUTPUTSUB
      wdm
      xce
      cpu      RTF65002
      rts

      cpu      W65C816S
INITSUB:
      lda      #2
      ldx      #1192
IS1:
      jsr      ADJSUB
      sta      P,x
      lda      P,x
      eor      #48
      jsr      OUTPUTSUB
      eor      #48
      jsr      UNADJSUB
      dex
      bpl      IS1
      rts

MULSUB:
      sta      R
      ldy      #16
M1S:   asl
      asl      Q
      bcc      M2S
      clc
      adc      R
M2S:   dey
      bne      M1S
      rts

DIVSUB:
      sta      R
      ldy      #16
      lda      #0
      asl      Q
D1S:   rol
      cmp      R
      bcc      D2S
      sbc      R
D2S:   rol      Q
      dey
      bne      D1S
      rts
      
ADJSUB:
      pha
      txa
      asl
      tax
      pla
      rts
UNADJSUB:   
      pha
      txa
      lsr
      tax
      pla
      rts
ADJ1SUB:
      pha
      txa
      asl
      tax
      pla
      dex
      rts
UNADJ1SUB:
      pha
      txa
      lsr
      tax
      pla
      inx
      rts

OUTPUTSUB:
      wdm      ; switch to 32 bit mode
      xce
      cpu      RTF65002
      jsr      DisplayChar
      clc      ; switch back to 816 mode
      xce
      cpu      W65C816S
      rep      #$30      ; acc,ndx = 16 bit
      rts

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BigEd

Post subject: Re: The RTF65002 Core

Posted: Tue Apr 08, 2014 9:34 am

Joined: Thu Dec 11, 2008 1:28 pm
Posts: 10985
Location: England

As you have a 65802 system, can you add some instrumentation to the code and debug the difference that way? Going around a 90m P+R loop does sound arduous!
Cheers
Ed

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Rob Finch

Post subject: Re: The RTF65002 Core

Posted: Thu Apr 10, 2014 4:32 am

Joined: Sun Dec 29, 2002 8:56 pm
Posts: 460
Location: Canada

BigEd wrote:

As you have a 65802 system, can you add some instrumentation to the code and debug the difference that way? Going around a 90m P+R loop does sound arduous!

The 802's not a system I've really used a lot in the past. I got it because I wanted the case at one point, but never really got around to using it. 90m P+R isn't really acceptable to me, so I tweaked the core a little bit and reduced the time to 10m. It's amazing how the slightest change can cause the P+R time to vary by a lot. It's because the core is complex so a slight change in routing makes/breaks it.

But, phew! I finally fixed the bug and now it works ! It displays the digits of PI. The bug was in storing 16 bit data, it would place the same data for both the first and second write cycles. It didn't matter with eight bit data.

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BigEd

Post subject: Re: The RTF65002 Core

Posted: Thu Apr 10, 2014 8:53 am

Joined: Thu Dec 11, 2008 1:28 pm
Posts: 10985
Location: England

That's great! And you got a quick-build option out of it too...

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ElEctric_EyE

Post subject: Re: The RTF65002 Core

Posted: Fri Apr 11, 2014 12:52 am

Joined: Mon Mar 02, 2009 7:27 pm
Posts: 3258
Location: NC, USA

Rob Finch wrote:

...90m P+R isn't really acceptable to me, so I tweaked the core a little bit and reduced the time to 10m. It's amazing how the slightest change can cause the P+R time to vary by a lot. It's because the core is complex so a slight change in routing makes/breaks it...

What are the spec's of your desktop machine Rob? That is a terrible time to wait! Also, what version of ISE are you using?

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Rob Finch

Post subject: Re: The RTF65002 Core

Posted: Fri Apr 11, 2014 3:54 am

Joined: Sun Dec 29, 2002 8:56 pm
Posts: 460
Location: Canada

ElEctric_EyE wrote:

What are the spec's of your desktop machine Rob? That is a terrible time to wait! Also, what version of ISE are you using?

I'm using a quad-core 3.4GHz machine (3 levels of caches) 12GB RAM with Webpack 14.4 (on Windows 8). Webpack sometimes describes the routing as "heavily congested" which may mean there is too much combo logic with not enough regs. Webpack reports using 600MB memory for the design.
I can easily do other things on my desktop (like browsing the internet or working on the software) while waiting. It's just the turn-around time for testing a bug fix can be annoying sometimes.

One issue with using a larger FPGA is the undoutbedly longer P+R times.

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Rob Finch

Post subject: Re: The RTF65002 Core

Posted: Tue Apr 22, 2014 5:57 am

Joined: Sun Dec 29, 2002 8:56 pm
Posts: 460
Location: Canada

RTF65002 now incorporates a spinlock (SPL) instruction. This instruction continuously polls a memory location until the contents of the memory location are non-zero.
The memory must be set to non-zero by another processor OR by an interrupt routine. (The SPL instruction is interruptible).
The instructions replaces spinlock code that looks like:

Code:

j1:
   lda   semaphore+1
   beq  j1

The code becomes just:

Code:

spl semaphore+1

The idea is to use the instruction in conjuction with hardware semaphoric memory. Note the new code is two bytes shorter and several cycles faster as a branch has been eliminated.

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barrym95838

Post subject: Re: The RTF65002 Core

Posted: Tue Apr 22, 2014 6:26 am

Joined: Sun Jun 30, 2013 10:26 pm
Posts: 1949
Location: Sacramento, CA, USA

If you execute a

Code:

spl 65002

do you trigger an Easter Egg?

Mike

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