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Thomas Jentzsch

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Thomas Jentzsch last won the day on March 9 2015

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About Thomas Jentzsch

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    Thrust, SWOOPS!, Boulder Dash, Star Castle, Aardvark...
  • Birthday July 18

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    Always left from right here!
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    Düsseldorf, Germany, Europe, Earth
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    Programming, (TV- :-) Sports, Travelling

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  1. Sorry, I didn't mean you can completely ignore it. But it should be almost always cached by MAM, so no Flash penalties there. Of course it still takes 1 CPU cycle then. BTW: The documentation suggests setting MAMTIM to 3 CCLKS (not 4 as I wrote above) for CPU speeds > 40 MHz.
  2. Do already have full MAM emulation implemented? I doubt that SRAM is slow at all. And it seems that with MAM = 2 Flash memory access speed becomes mostly irrelevant, S (always?) and N (mostly) are already in the latches. Only (far) branches may cause delays due to memory access. However with MAM=1 (N only) and especially with MAM = 0 (S and N), Flash memory access can play a major role. I found 50ns access time for LPC2103 Flash, which equals 4 cycles at 70 MHZ. Which will have a major impact given an average instruction time of ~2 cycles (based on opcode frequency sampling of some ARM games). This increases to ~4 (MAM = 1) and more than 7 (MAM = 0) cycles. These are worst case values, with Flash access only.
  3. I followed the same logic. Nevertheless I found this nowhere documented. Which doesn't mean that much, the cycle counting instruction is not very good, IMO. Looks like we have to speculate here. Or maybe do some testing on real hardware to find out.
  4. You are welcome. And another question: I notice that in case of a shift operation you only add the I-cycle if the shift is > 0. From which doc did you get this?
  5. I have the same doc. The questions is, if this is a conditional instruction. Then it is not always executed and would take only one S cycle if not executed.
  6. Agreed, valid assumptions. How are your stretchings defined? Integers? Also, couldn't you apply the stretching later on and only once? That would save some execution time, no? The doc says: "When the condition code of any instruction is not met, the instruction is not executed. An unexecuted instruction takes one cycle." In case of a conditional branch not taken IMO this implies that it takes only 1 cycle, no?
  7. Have you been able to verify your counts? I have added cycle counts to Stella lately too and wonder how precise they can become. Issues: I found no clear cut details in cycle count documentation what happens in case of a branch. I currently assume 1 cycle if not taken and 3 cycles if taken. Do you have different info or can you confirm this? The timing will change when MAM is disabled. Then Flash memory access will require extra cycles. Old Harmony carts have a CPU which has a MAM bug and therefore it is disabled by default. Do you have any info on how this affects the cycle count? Edit: I just read that you are addressing this already.
  8. No surprise. That version (3.9.3) is on RetroN 77 too. It's the last version without hardware graphics acceleration.
  9. I wonder which emulator they are using. I bet it is a modified version of Stella. Which would be illegal too without releasing their source code.
  10. I suppose you are right. Hopeless. I only looked up the console with the most games. But I doubt they have to remove Atari 2600 games for the smaller ones. BTW: They nicely marked all homebrews with "(unl)". Unlicensed?
  11. Maybe you can stop them from selling via Amazon, but Ebay? Looks like KINHANK ist the name of the pirating company. I am pretty sure there are many, many more pirated games on the console. Everybody buying one of these should be aware that he is profiting from theft.
  12. Homebrew list: 2005 Minigame Multicart (Usa) (Unl) Alfred Challenge (France) (Unl) Alien Greed (Usa) (Unl) Alien Greed 2 (Usa) (Unl) Alien Greed 3 (Usa) (Unl) Allia Quest (France) (Unl) Astar (Usa) (Unl) A-Vcs-Tec Challenge (Usa) (Unl) Avgn K.O. Boxing (Usa) (Unl) Backfire (Usa) (Unl) Bee-Ball (Usa) (Unl) Blip Football (Usa) (Unl) Boulder Dash (Usa) (Unl) Cave In (Usa) (Unl) Climber 5 (Usa) (Unl) Colony 7 (Usa) (Unl) Conquest Of Mars (Usa) (Unl) Cosmic Invaders (Usa) (Unl) Crazy Balloon (Usa) (Unl) Crazy Valet (Usa) (Unl) Cubis (Usa) (Unl) Dark Mage (Usa) (Unl) Duck Attack (Usa) (Unl) Dungeon (Usa) (Unl) Edtris 2600 (Usa) (Unl) Elevators Amiss (Usa) (Unl) Encaved (Usa) (Unl) Euchre (Usa) (Unl) Evil Magician Returns (Usa) (Unl) Fall Down (Usa) (Unl) Flapping (Usa) (Unl) Four-Play (Usa) (Unl) Gingerbread Man (Usa) (Unl) Go Fish! (Usa) (Unl) Gosub (Usa) (Unl) Gunfight (Usa) (Unl) Halo 2600 (Usa) (Unl) Hunchy Ii (Usa) (Unl) I Project (Europe) (Unl) Incoming! (Usa) (Unl) Inv (Usa) (Unl) Inv+ (Usa) (Unl) Jammed (Usa) (Unl) Joustpong (Usa) (Unl) Juno First (Usa) (Unl) K.O. Cruiser (Usa) (Unl) Lady Bug (Usa) (Unl) Lead (Usa) (Unl) Lord Of The Rings, The - Fellowship Of The Ring (Usa) (Unl) Marble Craze (Usa) (Unl) Medieval Mayhem (Usa) (Unl) Mental Kombat (Usa) (Unl) Merlin'S Walls (France) (Unl) Mine Sweeper (Usa) (Unl) Mondo Pong (Usa) (Unl) Okie Dokie (Usa) (Unl) Oystron (Usa) (Unl) Pac-Man 4K (Usa) (Unl) Pesco (France) (Unl) Phantom Ii - Pirate (Usa) (Unl) Pirate Special Edition (Usa) (Unl) Poker Squares (Usa) (Unl) Power Off! (France) (Unl) Pressure Gauge (Usa) (Unl) Rainbow Invaders (Usa) (Unl) Raster Fahndung (Usa) (Unl) Reindeer Rescue (Usa) (Unl) Rescue Bira Bira (Usa) (Unl) Revenge Of The Apes (Usa) (Unl) Scsicide (Usa) (Unl) Seawolf (Usa) (Unl) Skeleton (Usa) (Unl) Skeleton+ (Usa) (Unl) Solar Plexus (Usa) (Unl) Space Battle (Usa) (Unl) Space Instigators (Usa) (Unl) Space Treat (Usa) (Unl) Space Treat Deluxe (Usa) (Unl) Squish 'Em (Usa) (Unl) Star Fire (Usa) (Unl) Stell-A-Sketch (Usa) (Unl) Strat-O-Gems Deluxe (Usa) (Unl) Swoops! (Usa) (Unl) Sync (Usa) (Unl) Synthcart (Usa) (Unl) Tetris 26 (Usa) (Unl) This Planet Sucks (Usa) (Unl) Thrust+ Dc Edition (Usa) (Unl) Thrust+ Platinum (Usa) (Unl) Toyshop Trouble (Usa) (Unl) Ultra Scsicide (Usa) (Unl) Vault Assault (Usa) (Unl) Venture Ii - The Abysmal Abyss (Usa) (Unl) Video Simon (Usa) (Unl) Vong (Usa) (Unl) Warring Worms - The Worm (Re)Turns (Usa) (Unl) Warring Worms (Usa) (Unl) Yahtzee (Usa) (Unl) Z-Blocks (Usa) (Unl)
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