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Turtle Mode Query

Leigh Russ

Posts 7
06 Mar 2017 20:24


Hi,

Could anyone please possibly advise what the LEDs should do when Turtle mode is enabled and disabled? As I have been told contradicting information.

On mine the red ACT light stays on when the Vampire boots normally, and the light then goes off when Turtle mode is enabled. I have been told that this should be the other way round.

Cheers all


Philippe Flype

Posts 150
07 Mar 2017 06:35


to be precise :

open a cli. type the command 'cpu'.

>cpu datacache ==> Act LED Off
>cpu nodatacache ==> Act LED On

>cpu instcache ==> no change on Act LED
>cpu noinstcache ==> no change on Act LED

Turtle mode is linked to instcache.

  The 'Turtle' property enables a special feature
  of the core, that intends to improve compatibility
  with native Amiga games/demos or ProTracker-like
  programs, by slowing down the CPU to approximate
  the speed of a vanilla Amiga 1200 computer which
  is clocked at 14 MHz. Turtle mode does not change
  the behaviour of the CPU internal clock (eg.
  VP_CPU_Clock) but will insert waitstates into the
  pipeline.

BlitSync mode is linked to datacache.

  The 'BlitSync' property enables a special feature
  of the core, that intends to improve compatibility
  with native Amiga games/demos, fixing as many
  graphics glitches as possible. This is done by
  disallowing writes to the blitter registers for a
  short time, after starting a new job. This feature
  do not slow down the program execution but
  synchronizes chipset blitting.

Using WHDLOAD 'NOCACHE' will enable both modes, because NOCACHE will act as >cpu noinstcache nodatacache.


Pedro Cotter

Posts 6
07 Mar 2017 11:29


Hello,
  that could explain why Frontier is so slow on Gold2?

Thank you




Nixus Minimax

Posts 117
07 Mar 2017 11:49


Pedro Cotter wrote:
that could explain why Frontier is so slow on Gold2?

Frontiers isn't slow on Gold2. Just use an ordinary HDD-installation of Frontiers and not a WHDLoad-slave which for unknown reasons disables the caches.




Pedro Cotter

Posts 6
07 Mar 2017 12:33


Ha! Ok.. Thank you and moving on! :-)


Leigh Russ

Posts 7
07 Mar 2017 13:19


So the LED state is controlled by datacache. Which if I am not mistaken the cache is enabled by default, and therefore for a default status normal boot the ACT led should remain off?

If that is the case, then there's the question of why it is on for me and how to resolve and get it working proper?

posts 6