Amiga questions you've always been too embarrassed to ask

[mfilos]

Nope that gives me an output of: 100$$mhz (on OS3.2.1)
On stock 3.2.1 it gives the same output (100$$mhz)
On stock OS3.9 it works.
On stock OS3.1 it works.
On my OS3.9 (BB4) gives an output of: 1000 (wtf lol)

[TCD]

Should have added that I tested it on OS 3.1. I don't have 3.2.1 (it's weird that it behaves differentely...), so fingers crossed somebody finds the solution for 3.2.

[meynaf]

Tested under 3.0 :

set test 100
echo `get test`mhz

[mfilos]

@meynaf
You the man! It works just fine in 3.2.1 as well \o/

I used GetEnv (as the set was SetEnv) and still works as it should!
Thanks a lot both TCD and Meynaf

[thomas]

Originally Posted by mfilos

How on earth I can ommit the space in order to have 100MHz?

You have to tell it where the variable name begins and ends. You can do this with { and }.

set speed 100
echo "${speed}MHz"

[mfilos]

Fantastic Thomas! I didn't knew about the brackets!

[DDNI]

Here’s one. I know the CD32 CD device is in ROM. Now that I use a TF330 and load a workbench environment, how do I configure a CD audio playback program to play CDs on workbench? What is the name and unit number of the CD32 CD drive?

[Akiko]

I understand that a 68030 @50Mhz is nowhere near the same performance as a 68060 clocked at the same frequency. I can't recall but does the same rule apply for FPU's? So will a 68060 with a onboard FPU similarly outclass a 50Mhz coprocessor FPU on something like a Blizzard IV and by a significant margin?

[Supamax]

Some questions I always wanted to ask about WHDLOAD:
- games running (without WHDLOAD) on KS 1.2 and incompatible with later Kickstarts will run on a KS 2+ Amiga with WHDLOAD?
- games requiring ECS/AGA will not run on A500 + WHDLOAD, of course... right?
- what limitations does have the non-registered/paid version?
- is there a link where I can learn its informations/specs/features?
- a game requiring 0.5 MB will run on a WHDLOAD 0.5MB Amiga? I suppose not.
If so, which is the memory "overhead" required by WHDLOAD?
- games incompatible with later CPUs (more than 68000) will run on 680x0 Amigas with WHDLOAD?

[jotd]

- games running (without WHDLOAD) on KS 1.2 and incompatible with later Kickstarts will run on a KS 2+ Amiga with WHDLOAD?

yes. Generally those games use kickstart 1.3 emulation. You have to get kickstart 1.3 image + RTB (skick package) in DEVS:kickstarts

- games requiring ECS/AGA will not run on A500 + WHDLOAD, of course... right?

Of course not, but the error will be clear: whdload warns about missing AGA if slave requires it. It also warns about missing 68020+ it slave requires it. Same goes for 1MB chip (but it's very rare to require that).

BUT there are exceptions. One example that comes to mind: Master Axe won't run on 68000 because it uses some 68020 feature (even if HOL doesn't say anything about that limitation) but very locally so fixing it allows to run that game on a 68000/2MB chip (A600). So out of the box you need a A1200 because of 2MB+68020 but it can actually run on A600/68000/2MB.

- what limitations does have the non-registered/paid version?

None. whdload v18 is free from registration.

- is there a link where I can learn its informations/specs/features?

www.whdload.de

- a game requiring 0.5 MB will run on a WHDLOAD 0.5MB Amiga? I suppose not.

0.5MB total memory is just not enough for whdload. 2MB can allow to run 512k games. If you're talking of games requiring 512k chip, yes, most (recent) slaves respect the 512k chip requirement and don't ask for more.

- If so, which is the memory "overhead" required by WHDLOAD?

whdload needs to mirror the chipmem the game uses. Typically 512k. Then it has to keep memory for itself, stack... And it's best if it can PRELOAD the files else the screen will go black at each load (which requires as "OS swap")

- games incompatible with later CPUs (more than 68000) will run on 680x0 Amigas with WHDLOAD?

Of course. That's the main purpose of whdload since 1996. But whdload itself can only perform some generic tasks about that:
- set VBR to 0

- turn caches off (optional!)
- emulate instructions that were removed from 68060 (MOVEP)...

the slaves (specific piece of code adapted to games) handle the rest (disk/manual protections, stackframe error, self-modifying code, cpu-dependent loop, blitterwait errors... the list is just too long to quote here). That's where the challenge resides.

[coder76]

Originally Posted by Akiko

I understand that a 68030 @50Mhz is nowhere near the same performance as a 68060 clocked at the same frequency. I can't recall but does the same rule apply for FPU's? So will a 68060 with a onboard FPU similarly outclass a 50Mhz coprocessor FPU on something like a Blizzard IV and by a significant margin?

The 68030's external FPU 68882 is very slow compared to 68060's onboard FPU.
Sysinfo reports 1.33 MFLOPS for 68882@50 MHz, while about 28 MFLOPS for 68060@50MHz.

[Supamax]

@ jotd about WHDLOAD:
great answers, thanks!

[sandruzzo]

Originally Posted by Daedalus

Mach chips are CPLDs, which are used for controlling the accelerator's low-level functions, e.g. interfacing the CPU's bus with the Amiga's bus, controlling the RAM accesses, dealing with Autoconfig and so on. They're not CPUs or FPUs as such, but a collection of configurable logic circuits.


The 68k series has 4 major steps, and within each step you can generally say the clock speeds are comparable. Some differences (e.g. caches) will change things depending on the code however, so you can't really guarantee that except with the same CPU.

Those steps are: 68000 & 68010, then 68020 & 68030, then 68040, and finally 68060. Each step is a significant architectural change, and within a step is a more minor design change. The 68020 and 68030 for example are generally very similar except for the 68030's greater caches, which can give improved performance over a 68020 at the same clock speed (the RAM access of the '030 is also potentially faster but we're ignoring that).

The 68020/'030 is significantly faster than the 68000/'010 at many things, e.g. multiplication and division, so if code uses these a lot then the 68020/'030 will run it much faster at the same clock speed. And you see similar differences when moving to the 68040 and 68060 steps. Additionally, memory accesses from the '020 up are usually done over a 32-bit bus, whereas the 68000/'010 uses a 16-bit bus which means many operations can take longer to complete because 32-bit values have to be transferred over two cycles instead of one.

Basically, it will depend on the code from case to case, and there will always be exceptions, but in general, at e.g. 25MHz an '060 will be faster than an '040, an '040 will be faster than an '020/'030, and an '020/'030 will be faster than an '000/'010.

What about Freescale ColdFire step over 060?

[oscar_ates]

Stock A1200 could not play the 2.5D FPS games properly

[Daedalus]

Originally Posted by sandruzzo

What about Freescale ColdFire step over 060?

What about it?

[Weasel Fierce]

Originally Posted by Supamax

- games requiring ECS/AGA will not run on A500 + WHDLOAD, of course... right?

It is worth noting that there are very very few games requiring ECS so its mainly AGA you are going to be missing out on.


Some benefits of WHDLoad that are not mentioned as much but which are also quite nice!

Installs bypass or remove copy protections.
Many installs add trainers, additional control options etc. F.x. many games now support two button joystick or CD32 pads.
Some even seem to fix some errors and bugs causing game crashes.

[gimbal]

What I like about the trainers in slaves is that they generally don't require a button press to continue, which works wonders on the A500 mini for example. Most cracktros require pressing a mouse button which is a right bother when you're gaming on the couch.

[Supamax]

Originally Posted by Weasel Fierce

Some benefits of WHDLoad that are not mentioned as much but which are also quite nice!

Installs bypass or remove copy protections.
Many installs add trainers, additional control options etc. F.x. many games now support two button joystick or CD32 pads.
Some even seem to fix some errors and bugs causing game crashes.

I agree, it's a HUGE and GREAT work.

[Thomas Richter]

Originally Posted by sandruzzo

What about Freescale ColdFire step over 060?

The coldfires are embedded controllers and not full CPUs, which makes the comparison hard. They do run at higher clock speeds, but offer only a subset of the 68000(!) instructions. For example, all arithmetic instructions only exist in a 32-bit (long word) variant, and all other variants trigger an invalid instruction exception. "add.w d0,d1" is an invalid instruction on coldfires.

[mfilos]

Is there a binary available that I could get screenmode info in order to save them to variables?
Like for example Resolution (width/height), Color depth etc?

For other variables like Chipset, CPU, FPU, VideoMode etc I found out AmigaT that does the job.