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Search: Posts Made By: frank_b
Forum: Coders. Asm / Hardware 17 November 2018, 17:55
Replies: 834
Views: 28,292
Posted By frank_b
Hmm.. maybe the 20% increase was with 4 planes...

Hmm.. maybe the 20% increase was with 4 planes active. I did see a difference between running the code from fast RAM and from chip. I'll have a dig about my 1k drive and see if I can find it later...
Forum: Coders. Asm / Hardware 17 November 2018, 09:57
Replies: 834
Views: 28,292
Posted By frank_b
About 20% IIRC. It was a regular fast RAM card....

About 20% IIRC. It was a regular fast RAM card. Nothing fancy.
Forum: Coders. Asm / Hardware 17 November 2018, 09:47
Replies: 834
Views: 28,292
Posted By frank_b
Code containing nothing but shifts and branches...

Code containing nothing but shifts and branches executes faster from fast RAM. Even if all bitplanes are switched off. I believe I tested this on an NTSC Amiga 1000 a year or so ago.
Forum: Coders. Asm / Hardware 16 November 2018, 12:53
Replies: 834
Views: 28,292
Posted By frank_b
Let's just agree that the ST/Amiga would handily...

Let's just agree that the ST/Amiga would handily outrun an 8086 at the same clock :)
Forum: Coders. Asm / Hardware 16 November 2018, 08:12
Replies: 834
Views: 28,292
Posted By frank_b
Don't forget that cycle counting only happens on...

Don't forget that cycle counting only happens on ST RAM/Chip RAM. ROM access is not affected on either machine. Branches and shifts tend to be faster than in chip RAM. Even for <4 planes.
Forum: Coders. Asm / Hardware 15 November 2018, 22:19
Replies: 834
Views: 28,292
Posted By frank_b
Indeed it is possible that the prefetch will...

Indeed it is possible that the prefetch will stall the CPU whilst waiting for main memory to fetch opcodes.

I rewrote that for you to match what is said in the Abrash book.
Add the best and worst...
Forum: Coders. Asm / Hardware 15 November 2018, 00:38
Replies: 834
Views: 28,292
Posted By frank_b
Only impressive if you forget about the cost of...

Only impressive if you forget about the cost of filling the prefetch buffer. The 8086 and 8088 are much slower than they appear to be from Intel's documentation. At least according to the Zen of...
Forum: Coders. Asm / Hardware 14 November 2018, 17:28
Replies: 834
Views: 28,292
Posted By frank_b
Do your 8086 timings take into account memory...

Do your 8086 timings take into account memory accesses during prefetch?
Every opcode fetch is going to cost cycles.
Can you please add best case/worst case columns for 8086.
Forum: Retrogaming General Discussion 11 November 2018, 15:00
Replies: 20
Views: 778
Posted By frank_b
Bigger blits were possible on ECS. Separate width...

Bigger blits were possible on ECS. Separate width and height values. Borderblank was another edition. I don’t think anything would have been used in games. Perhaps extra chip memory?
Forum: Coders. Asm / Hardware 05 November 2018, 07:24
Replies: 834
Views: 28,292
Posted By frank_b
There's another interesting article earlier on in...

There's another interesting article earlier on in that issue. A system designer discounting the 286 out of hand because it's "at least a generation behind the 68000".
Forum: Amiga scene 31 October 2018, 08:32
Replies: 375
Views: 28,617
Posted By frank_b
Can't we just have a kickstarter and buy them all...

Can't we just have a kickstarter and buy them all out? They must be worth pennies these days. Buy them out and open source the lot.
Forum: support.Other 06 October 2018, 11:03
Replies: 7
Views: 450
Posted By frank_b
You should be able to use easyadf from amiga kit...

You should be able to use easyadf from amiga kit and cross dos on your 1200 for this. :)
Forum: Retrogaming General Discussion 28 September 2018, 12:20
Replies: 144
Views: 7,214
Posted By frank_b
No. Certainly not. It is nowhere near as elegant...

No. Certainly not. It is nowhere near as elegant as the original design. Everything extra s compromised. The sprites can't be reloaded as there's no DMA register for the extra control words. You...
Forum: Coders. Asm / Hardware 19 August 2018, 23:55
Replies: 834
Views: 28,292
Posted By frank_b
How far can you conditionally branch in a 68k vs...

How far can you conditionally branch in a 68k vs an 8086? It's +-32k on the 68k vs +-127 bytes (yikes) on the 8086.

Here are some other interesting questions.

How many registers do you have...
Forum: Coders. Asm / Hardware 14 August 2018, 20:18
Replies: 834
Views: 28,292
Posted By frank_b
Anything is better than the 8086. I like the 6502...

Anything is better than the 8086. I like the 6502 and the 68000. The 8086 is frickin' hideous.
Forum: Amiga scene 09 August 2018, 22:00
Replies: 128
Views: 8,799
Posted By frank_b
Reading the HRM 25 years later and STILL being...

Reading the HRM 25 years later and STILL being impressed. The Amiga wasn't a computer. It was a work of art.
Forum: support.Hardware 03 August 2018, 10:04
Replies: 25
Views: 1,663
Posted By frank_b
It was an amazing chip in 1993. There must be...

It was an amazing chip in 1993. There must be faster versions around these days :)
Seems it topped out at 250 mhz in 2010.
Forum: Nostalgia & memories 10 July 2018, 17:39
Replies: 106
Views: 12,874
Posted By frank_b
My pet peeves. 1) Same 7 mhz cycle access as...

My pet peeves.

1) Same 7 mhz cycle access as ECS/OCS. I *bet* the 1200 was going to ship with a 68000 oroginally! I think they were going for 100% compatibility on games.
2) Bank switched...
Forum: Coders. General 09 July 2018, 18:14
Replies: 587
Views: 48,353
Posted By frank_b
Add a bus master one to the sidecar slot. It...

Add a bus master one to the sidecar slot. It could run much faster to/from fast RAM and cover the full address range.
Forum: Coders. General 09 July 2018, 17:06
Replies: 587
Views: 48,353
Posted By frank_b
like leaky batteries :D

like leaky batteries :D
Forum: New to Emulation or Amiga scene 09 July 2018, 13:02
Replies: 45
Views: 3,370
Posted By frank_b
If you mean in comparison to a 16 bpp display I'd...

If you mean in comparison to a 16 bpp display I'd have to disagree.
Ham8 is far inferior compared to the flexibility of a high colour or true colour display.
Forum: Coders. General 07 July 2018, 19:54
Replies: 587
Views: 48,353
Posted By frank_b
I know how to write a fast software sprite...

I know how to write a fast software sprite routine ;)
https://www.exxoshost.co.uk/atari/last/blitter/index.htm

The one in the linked intro above at the end of the page calculates the masks on...
Forum: Coders. General 07 July 2018, 17:09
Replies: 587
Views: 48,353
Posted By frank_b
You could buy 4 meg STe machines direct from...

You could buy 4 meg STe machines direct from dealers back in the day. Industry standard SIMM sockets. It's stock in that there's nothing fancy added like an accelerator card. You can add fast RAM /...
Forum: Coders. General 06 July 2018, 22:49
Replies: 587
Views: 48,353
Posted By frank_b
Ok I will do the math for 500 16*16 sprites at...

Ok I will do the math for 500 16*16 sprites at say 16 colours with the CPU.

You're reading 2 bytes per line per plane * 16 for the sprite: 2*4*16 = 128 bytes.
The mask takes 2 bytes per line * 16...
Forum: Coders. General 06 July 2018, 19:42
Replies: 587
Views: 48,353
Posted By frank_b
Cho ren sha has up to 4000 sprites on screen or...

Cho ren sha has up to 4000 sprites on screen or something equally crazy. Forget about that on a non 060 1200. I'm talking about the arcade ports here. That's more feasible.
Forum: Nostalgia & memories 06 July 2018, 19:38
Replies: 106
Views: 12,874
Posted By frank_b
The half speed (7 mhz vs 14 mhz) is the wait...

The half speed (7 mhz vs 14 mhz) is the wait state. The ROM is likely running at 14 mhz however. Amiga reloaded will allow the 020 to hit chip RAM at full 14 mhz speed regardless of what the chipset...
Forum: Coders. General 06 July 2018, 17:57
Replies: 587
Views: 48,353
Posted By frank_b
A full 68k bus master blitter, with the same...

A full 68k bus master blitter, with the same register interface as the Amiga would be a hell of a nice USP for new ACA 500 cards. :D
Would do wonders for fblit too.
Forum: Coders. General 06 July 2018, 17:27
Replies: 587
Views: 48,353
Posted By frank_b
Chuck hardware at it? Why not? :) There will be a...

Chuck hardware at it? Why not? :) There will be a Falcon version too. A500 owners will be out of luck though. It's possible on a stock 8 mhz STe however. It would be good to see a version on the...
Forum: Coders. General 06 July 2018, 15:21
Replies: 587
Views: 48,353
Posted By frank_b
That said you could probably get away with...

That said you could probably get away with storing all the sprite data for the player in fast RAM. CPU could just copy into the chip ram buffer and adjust the positing via control words. That would...
Forum: Coders. General 06 July 2018, 14:00
Replies: 587
Views: 48,353
Posted By frank_b
Performance gains from using sprites won't help. ...

Performance gains from using sprites won't help. The issue is the memory usage required and the performance hit from buffering from fast to chip on a 68k machine. I already gave some rough estimates...
Forum: Coders. General 06 July 2018, 11:33
Replies: 587
Views: 48,353
Posted By frank_b
How much memory is required for the graphics? ...

How much memory is required for the graphics? This version needs 4 meg of unified memory on an STe. It may exceed even 2 mb of chip RAM for some levels.
Masking performance should be similar on...
Forum: Retrogaming General Discussion 18 June 2018, 20:03
Replies: 145
Views: 7,371
Posted By frank_b
That would solve the scarcity of CD32 controllers...

That would solve the scarcity of CD32 controllers quite nicely! :)
Forum: Coders. Asm / Hardware 01 May 2018, 09:02
Replies: 17
Views: 985
Posted By frank_b
Try TAS from chip RAM on a 500..Buzzing black...

Try TAS from chip RAM on a 500..Buzzing black screen of death and a trip to the power button!
Forum: Coders. General 21 April 2018, 18:55
Replies: 587
Views: 48,353
Posted By frank_b
Conversions and porting. Not the same thing ;) ...

Conversions and porting. Not the same thing ;) One is harder than the other. No source code on a binary conversion ;) Reversing games is challenging from personal experience. I did it commercially...
Forum: Coders. General 20 April 2018, 17:20
Replies: 587
Views: 48,353
Posted By frank_b
What happens if the weaker system wasn't taken...

What happens if the weaker system wasn't taken into account when the game was designed? Sounds like the game would have to be hacked to bits or significant time would be spent optimising every last...
Forum: Coders. General 20 April 2018, 10:18
Replies: 587
Views: 48,353
Posted By frank_b
I'm sorry but you may have misunderstood. That's...

I'm sorry but you may have misunderstood. That's completely wrong. It is more time consuming to port downwards.
Forum: Coders. General 19 April 2018, 20:42
Replies: 587
Views: 48,353
Posted By frank_b
Sorry but a game dev is always going to prefer to...

Sorry but a game dev is always going to prefer to port upwards. It's easier and time is money. There is no reason why the more powerful machine version can't be tweaked however. A port isn't...
Forum: Coders. General 06 April 2018, 21:10
Replies: 587
Views: 48,353
Posted By frank_b
Not enough chip bandwidth for six bit high res...

Not enough chip bandwidth for six bit high res ham.
Forum: Coders. General 06 April 2018, 18:00
Replies: 587
Views: 48,353
Posted By frank_b
The only major oddity was that it wasn't fully...

The only major oddity was that it wasn't fully compatible with the 68k. TAS <cough>
Forum: Retrogaming General Discussion 06 April 2018, 01:47
Replies: 35
Views: 1,376
Posted By frank_b
Fixed point coordinates perhaps? It's possible to...

Fixed point coordinates perhaps? It's possible to have a 50 hz game update on screen objects with fractional fixed point values. That way every object doesn't have to move at a linear 50 fps.
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