Emulator that can set exact speeds?

[Weasel Fierce]

Perhaps a stupid question. Does any of the Amiga emulators have the ability to set a specific Mhz speed? f.x. if i wanted to set it to exactly (or as close as possible) an 030/25 f.x.

[Marce]

Originally Posted by Weasel Fierce

Perhaps a stupid question. Does any of the Amiga emulators have the ability to set a specific Mhz speed? f.x. if i wanted to set it to exactly (or as close as possible) an 030/25 f.x.

winuae can set exact speed of the A500, the A1200 and let's say A1200+ 28mhz turboboard (8x)
also you can regulate the speed using the cpu speed slider then you can check on sysinfo at what speed is running etc then you can match the Amiga you want emulate

[Weasel Fierce]

That makes sense, thanks

[Seiya]

using cycle_exact you and setting a custom cpu_multiplier you can find more or less exactly speed in integer operations. There is no way to emulate exactly 881/882 at fixed frequencies (16, 33, 40 and 50 Mhz).

[Daedalus]

Originally Posted by Marce

winuae can set exact speed of the A500, the A1200 and let's say A1200+ 28mhz turboboard (8x)

CPU cycle-exact emulation is only guaranteed for the 68000. Setting an A1200 to be cycle-exact will only be cycle-exact as far as the chipset & chip RAM accesses are concerned.

[Marce]

Originally Posted by Daedalus

CPU cycle-exact emulation is only guaranteed for the 68000. Setting an A1200 to be cycle-exact will only be cycle-exact as far as the chipset & chip RAM accesses are concerned.

yes the A1200 speed is not very exact
ie if you set in winuae 4x A1200 the emulation will be a bit faster than a real A1200 + fast ram
idem if you set 8x will be a bit faster than a real A1200+ TRA1200 turboboard or blizzard 1220 which both run at 28mhz and reports 5 mips on sysinfo

also the speed on winuae could be affected by the video filter you are selecting, resolution and x86 speed etc

the best way to match the speed of certain Amiga computer +accel is disabling cycle exact and using sysinfo to test the speed of your emulation and regulate it using the cpu slider until you set similar numbers

[jotd]

I would love to see a "slow chip" feature to emulate the slow chipmem access that you get when you plug accelerator boards in and code runs in chipmem.

My Phase 5 060 board makes chipmem code run super-slow.

[alexh]

Originally Posted by jotd

My Phase 5 060 board makes chipmem code run super-slow.

That is not that uncommon. If I understand it correctly some Amiga accelerators cheat and don't implement the 68000 bus cycles exactly as described in the 68000 HRM which can have the advantage of being ready early and always meeting the CPU slot for bus access. If you model the bus 100% as described and for whatever reason the accelerator misses it's bus slot then it has to wait.

I believe this is what happens with PiStorm.

[amigatv]

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