[Coco] CoCo3 accelerator add-on

[Luis Antoniosi (CoCoDemus)]

i made some experiments and it didn't make much difference at all.my
bottleneck is that I need to load each instruction, dispatch a jmp table
for each instruction and perform each instruction in 6809.

add, sub, cmps have all 6809 similars but not for the flags. It spends a
considerable amount of time translating the 6809 flags to 8080/z-80, and
also, the 6809 doesnt perform half carries in subtractions, etc. so
basically i have one instruction to perform the code and dozen to set the
proper 8080 flags.

for example, the ADD instruction:

_add8 pshs cc
sta <A
andb #~(SF|ZF|HF|PF|NF|CF)
puls a
bita #%00100000
beq @nHF
orb #HF
@nHF bita #%00001000
beq @nSF
orb #SF
@nSF bita #%00000100
beq @nZF
orb #ZF
@nZF bita #%00000010
beq @nPF
orb #PF
@nPF bita #%00000001
beq @nCF
orb #CF
@nCF stb <F
rts
_ADD8 MACRO
ldd <AF
adda \1
lbsr _add8
ENDM

ADDAA _ADD8 <A
_FETCH
ADDAB _ADD8 <B
_FETCH
ADDAC _ADD8 <C
_FETCH
ADDAD _ADD8 <D
_FETCH
ADDAE _ADD8 <E
_FETCH
ADDAH _ADD8 <H
_FETCH
ADDAL _ADD8 <L
_FETCH


maybe later i will add some queue as it adds some bugs to the vt-52
emulation.


On Sat, Apr 27, 2013 at 11:31 PM, L. Curtis Boyle
<curtisboyle at sasktel.net>wrote:

> Don't forget to try buffering your characters so that you can do a larger
> (and less often) I$Write calls... it will make a big difference. :)
>
> L. Curtis Boyle
> curtisboyle at sasktel.net
>
>
>
> On Apr 27, 2013, at 9:25 PM, Luis Antoniosi (CoCoDemus) wrote:
>
> > my cp/m emulator would run faster too :)
> >
> >
> > On Sat, Apr 27, 2013 at 11:04 PM, Nick Marentes <nickma at optusnet.com.au
> >wrote:
> >
> >> Here's an idea I've been tossing around for awhile and wonder if it is
> >> possible/feasible.
> >>
> >> The GIME chip is so tied down to the speed of the 6809 in order to keep
> >> video syncronised for output to a monitor.
> >>
> >> As we've seen in the past, clocking up the 6809 just makes the GIME lose
> >> video sync.
> >>
> >> What if a replacement 6809 could be created using an FPGA with adaption
> to
> >> fit the standard 6809 socket?
> >>
> >> The FPGA would ensure that the signals to the GIME remain what it
> expects
> >> but internally, it can process much faster.
> >>
> >> This will be similar to Sock Master 4Mhz mod which made the 6809 slow
> down
> >> when being accessed by the GIME (or vice versa) but number crunching can
> >> run at a higher rate.
> >>
> >> A faster CoCo3 opens the doors to more complex programs such as a Wolf3D
> >> game (graphics still at old speed but number crunching for the math much
> >> faster).
> >>
> >> Possible? Another pipe dream?
> >>
> >> Nick
> >>
> >> --
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> http://five.pairlist.net/mailman/listinfo/coco>
> >>
> >
> >
> >
> > --
> > Long live the CoCo
> >
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> >
>
>
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