c64 vs Amiga demo coding...

[Plagueis/KRX]

In another thread (re: Blitter Sweet) Photon said:

hehe, I was explaining to Andreas why I prefer the limitations of the standard platform that A500/0.5chip/0.5fast is, and don't make demos for a beefed up PowerPC Amiga. I prefer it because it's an absolute to measure demos by, it's limits are small enough to post a challenge and big enough to do nice stuff with, and if you're good you can make something that looks good even to outsiders, and not just to people who knows what the hardware can do and how much work is involved to make the effect. An effect always looks better when you know what's possible and not possible.

When I look at an Amiga demo, I can dissect it into it's component parts, notice any tricks that are there, and can even figure out fragments of code needed to do it. Then, once in a while, a demo knocks me off my feet and makes me go "wtf...how the..." ...for a while, at least. That brings a deeper level of appreciation. I'm sure it's the same for C64 coders with C64 demos.

I fell in love with the 65xx CPU from when my Acorn Atom days, the 68xxx family isn't as clean to me, even though it has a capable instruction set and is straightforward to program. It's toying with the chipset that turns me on, and the Amiga can simply do more neat things if you go crazy with it.

...I can see a lot of your points there dude...especially in regard to wanting to have a "standard" platform for coding demos on, which has some homogeneity, a factor which is a big deal if you value things like being able to compare one effect to another, and one demo to another, without having to account for differences in chipsets and hardware configuration. That could be one reason the c64 seems to have a more unified and consolidated scene, since there is less diversity in hardware configurations, and therefore the demo community tends to be less factionized. Of course, there are other factors at work there too, with the c64, such as how long it's been around, and how much smaller the instruction set is. It's a lot easier to master and even memorize the opcodes, and even more their mnemonic equivalents.

I'm still a relative newcomer to making demos on the c64, only having started in late 2007. I've released (or co-released) 5 or 6 products now, mostly consisting of intro type pages (and one 3 part demo) which try to showcase the new effects and tricks I've learned along the way. One of my parts was inspired by the Skid Row crack intro of Double Dribble on the Amiga. I sat there watching it thinking..."I wonder how I could implement that effect on the c64?" I started sketching things down in my notebook, and a few days later I had it. It was actually a lot of fun...the effect in question was the scroller where characters are rotating around Z as in the axis extending perpendicular to the monitor toward the viewer.

I can see how that design/development topology could work in reverse on the Amiga (once I start to master its custom chipset). See a cool effect on a c64 demo...and knowing already how they did it, imagine a way to implement the same thing on the Amiga, yet take advantage of the blitter, copper, etc to get fancier with that routine and take it to the next level.

I agree about the elegance of the 65xx family of processor, about how it seems "cleaner", yet as I study the Amiga in depth for the first time, it seems less "dirty" the more I learn. I think coding 6510 (er, actually the VICII, which is what you are really coding when you make 64 demos) and the 68k[Denise/Paula/Agnes] simultaneously, at this point for me is complimentary...especially for my design/style skills. I think that's where the real prize lies when porting between these two systems.

-Brett

[WayneK]

I agree totally, I find myself thinking of effects that would be more suitable for other machines while I'm coding another - just leads to more interesting coding on multiple platforms!
At least, that's the theory... usually I just file it away in the TODO list and go back to sleep.

[pmc]

Originally Posted by WayneK

I find myself thinking of effects that would be more suitable for other machines while I'm coding another

Got any of those cool coding effects to show us?

[Plagueis/KRX]

Originally Posted by pmc

Got any of those cool coding effects to show us?

Yes! I would love to see something from your mind's eye make it to the raster!!!

I'm working on my stuff...but it's going to probably be at least a few more weeks or more before my first 'one part' demo on the Amiga. I really need to learn all the basics first.

-DP

[Photon]

OK, checked out a few KrionyX demos on Youtube - if you are so inclined, please share them on Pouet.net and Demoscene.tv so sceners can find them easily and their release is noted. (Unless there's a division between European and US demoscene and they've already been released on US equivalents that I ehm have no idea what they are.)

Maybe I'm stuck in my European scene, I wouldn't know, hehe. But it seems to me US prods are rare?


AAAnyway. Notepad sketching=good idea I think I will have a gridpaper notebook on my desk on the day I croak :P

With excuses beforehand for any mistakes:

To learn Amiga coding, basically you can go from any assembler platform, and to understand how the Amiga works, just add "CPU and custom chips fight over the chip memory" (where sound samples, picture buffers, and blitter I/O data resides). Basically you have 1/50 or in your case 1/60 second worth of DMA word accesses to the chipmemory. If the CPU is calculating internally and code resides in true fast-memory, it doesn't need a single of those cycles. That means you can have all the bitplanes on, reading from disk, showing sprites, running the copper, playing samples, all that jazz (by which I mean DMA accesses) at the same time as running code at full speed.

If you want the demo to run on 0-fastram Amigas (A500/+, A1200, even A4000T came in 0 MB fastmem variants I think) however, you need to write the code to run in chipmem and take into account this DMA vs CMA fight. If it runs at acceptable speed then, you know that's the slowest it will go.

If you leave this base platform and go for AGA+fastmem, run the code in fastmem and minimize data access to chipmem from the CPU. Then, basically only > 4 bitplanes will affect CPU performance, and the only other big chipmem-cycle-hogger is the blitter, and only while it is blitting, ofc.

This was to get good performance and to understand how the chips interact. A fixed platform is good to compare performance ofc, but sooner or later the limit will be hit. Finding (out what sets) the limits is a nicer challenge to me than 'beating another guy's dot count or bob record' nowadays, ie. a demo can be perfect and impossible to improve significantly; the demo is good in an absolute way instead of in a relative way. Competition is sometimes very much in the way of innovation.

Coppershade.org was supposed to have coder's tutorials, and even though a few have been written, as usual I swarm myself with more "gotta finish" projects, sigh...

If you want a starting point, get Hardware Reference Manual and a bible. The latter being a proper Programmer's Manual for the CPU model you intend to code for. If you already have these, you have the facts.

From there I suggest very simple experiments (experimenting is by far the most enjoyable time spent in an assembler to me ), like starting up a screen and plotting pixels... "OK, now I can plot pixels with the CPU... now to move them I need a clearscreen blit... OK, they're moving. What can I make with them..." etc etc

Just saying experimenting is fun and lets the real behavior of the chipset be properly implanted in your brain :P If you're good you can just start coding a demo and look things up in HRM. Assembler, hardware register include file or a register map, and some converters for music and graphics and off you go.

I'm a bit skeptical to the porting thing, for one it's not certain it's done the same way at all on Amiga, and secondly the Amiga chipset has so many more possibilities - it was made to be explored...

Certainly the NTSC demoscene platform has had very little attention devoted to it when it comes to performance limits and which effects are possible, so you could be elite in no time, hehe

Edit: For sure, you will be happy to get rid of the anal raster timing, it will be a doddle to use the copper I think! If you want inspiration I thought of Mahoney & Kaktus on Amiga, who both came from C64.

[Plagueis/KRX]

Photon,

Well, there's nothing special in the grand scheme of things about my KrionyX stuff so far, it's basically a personal documentation of the learning process in demo form...at least that's the way I mostly see it, that and an expression of my desire not to see the "old school" colorful schemes and "hit spacebar" traditions of the old 64 scene pass completely under the shadow of modern PAL trackmos with trendy effects, and pastel color schemes. Mind you, my favorite demos are PAL, of course, but were talking about 10's of thousands of demos versus a few hundred, so a simple consideration of statistics predicts the best stuff is European. And yes, your observation is correct...very few people from North America and Japan (NTSC) made demos, and today, there are less than a handful of guys actively coding in the U.S. I am relatively proud of the fact that I overcame a lot of stigma and doubt to enjoy the limited success I've had in the community. I am also in The Phantom's group "Forces of Evil", who recently released a halloween demo..my page was the 2nd, where I have an expanded sprite scroller in the side borders, as well as a group abbreviation logo made of raster splits (a lot harder on the c64 than the amiga...have to be cycle exact timed). I figured out how to open the side borders using "dec $d016, inc $d016" at just the right cycle (listening Paul?)...that was a fun moment, and as you say, it came through experimenting with assembly, and the hardware.

I do have the HRM as a text file, and Paul gave me the .pdf, so I'm very well set, and I have an instruction set for the 68k as well. Also, I won an actual paperback HRM off of ebay and it is on the way, but it was shipped from the U.K., so I don't know when to expect it. I've been learning a lot in the exact manner you describe, so it's good to know that I'm on the right track. It's a lot of new techniques and things to get used to, but every day I find my control over the chipset aggrandizing.

As far as porting goes, I don't think I really should have used the term "porting" per se...I was speaking more conceptually, like from a design perspective. You see something that looks good in a demo on one machine, and wonder how you might be able to take that concept and express it in code on the other machine, both as a technical challenge to yourself, and also a way to make the effect look nicer/"cooler" in its new incarnation on another architechture/chipset. I did that with the rolling characters effect on the Skid Row cracktro and took it to the c64. In the process I had to learn several new coding techniques. So it expanded my mind from both and technical and creative point of view. Not that I plan on doing that very often, since making something from scratch is probably most rewarding....but every now and then. Or it could be that I am not very creative and this is my form of denial. That would at least make me somewhat creative though.

You mention that NTSC demo territory is mostly virgin. I'm not surprised, but if I follow my likely course and begin to write code for Retro, I'll be coding PAL routines...which might make it harder to test my code on my A500 OCS hmmm. The prospect of eventually making NTSC products on the Amiga is interesting, but not that compelling without at least one other person to talk to about it. A lot of this, for me, is about the human element...talking to each other about code, new routines, ideas, fun past times. That's what I like about the CSDb, always something going on, being released, people to talk to, things happening. Of course, people here are very nice, generous and a bit less self important. No information is too proprietary to share...and I like that!

Kaktus and Mahoney!!! I love their stuff. I have always liked their C64 demos..with unreadable scrollers (like their ROR scroller for instance) and interesting tunes. In their scrolltexts they talk about how they are about to "go Amiga" and then I guess they did. A couple of nights ago I watched one of their amiga demos...the one with goldfish sprites (or were they bobs) swimming around and crazy samples.

I actually enjoy the anal process of counting cycles...I guess it reinforces the feeling of being in control of the hardware (the thing that makes a demo a demo) and it's a big reward when I add up the cycles from a bunch of instructions, run the program and find that my arithmetic was correct and the routine works bug free! It was a 2 year struggle getting to that point and I still have much to learn on the C64, not to mention the Amiga.

Thanks for your ideas Photon!

-Brett
Darth Plagueis/KrionyX/Forces of Evil/Avatar

[Photon]

NTSC or PAL, well there's not many doing OCS stuff on either platform at the moment, depends on if you want to show off across the pond or domestically I guess :P

If you have a 15KHz RGB CRT-monitor such as C1081 or C1084s, it should take both signals (but not via non-RGB such as composite, must be an RGB cable), and you can use the brick power supply for both Amigas.

I do have some spare A500s if that's what you want to code on... let me know and I can give you a good price for one with 1MB memory and an external drive.

If you have or buy an A500+ domestically, I think you can mod it with some tracecutting, soldering two points and changing the crystal. ECS models and up support both ntsc and pal video out, but CPU runs at NTSC speed. Correct me if I'm wrong someone.

You can code for NTSC, then test in WinUAE with PAL timings - however keep in mind, Cycle Exact is pretty accurate but not perfect. And I am not one to discourage coding on the real thing

Coding for PAL in America could surprise some sceners here in a good way I think

[Plagueis/KRX]

Photon,

Originally Posted by Photon

NTSC or PAL, well there's not many doing OCS stuff on either platform at the moment, depends on if you want to show off across the pond or domestically I guess :P

Well, first and foremost I am a realist. Most of the people (if any) who end up watching my stuff will be in Europe. Also, that's where the parties are taking place (although I'm not very interested in competition with others..at least not at this point, and maybe never) and where the real action is with demos. Over the last couple years, I've tried to cause unity, solidarity, and growth in the NTSC demo scene on the 8-bit computer I've spoken of before. I've been somewhat disappointed at the reaction. I seem to be the only American (or maybe one of two) who is this obsessed with coding demos right now, in 2009. So I want to join in the fun with you guys...where the action is going on...Sweden, Germany, UK, Poland, lots of people who make the time to code and pixel, and make cool tunes.

And as far as OCS...it's the Amiga I bought in 1988 and enjoyed until 1992 (when a power surge killed it).

Originally Posted by Photon

If you have a 15KHz RGB CRT-monitor such as C1081 or C1084s, it should take both signals (but not via non-RGB such as composite, must be an RGB cable), and you can use the brick power supply for both Amigas.

I have one (1084s), but it's in use on the 64. I may give the c64 a color TV temporarily, or possibly buy another C1084s for my A500 off of ebay or somewhere.

Originally Posted by Photon

I do have some spare A500s if that's what you want to code on... let me know and I can give you a good price for one with 1MB memory and an external drive.

Yes. A PAL Amiga is a great opportunity. Save one for me, and I should be able to get it from you in about a month or so. I'm also looking for a PAL c64 for that same reason, so if you see any deals PM me.

Originally Posted by Photon

If you have or buy an A500+ domestically, I think you can mod it with some tracecutting, soldering two points and changing the crystal. ECS models and up support both ntsc and pal video out, but CPU runs at NTSC speed. Correct me if I'm wrong someone.

Actually the A500 I have now is strange. My original Amiga was definitely an OCS, as it was purchased back in 1988, but in 1992 it was destroyed by a lightning related surge during a storm. A few years ago a friend gave me his old A500, which was a bit newer than mine. Some of my old OCS demos and intros seem to be broken on it. It isn't however, an A500+. The power LED is green, and the drive led is yellow, however on my original Amiga the Power LED was red while the drive LED was green. I don't know if this is significant to the chipset, but perhaps I have an ECS Agnus only and not a full ECS. Isn't there such an A500? Back in my Amiga "prime", there was only the OCS A500, 2000, and 1000.

Originally Posted by Photon

You can code for NTSC, then test in WinUAE with PAL timings - however keep in mind, Cycle Exact is pretty accurate but not perfect. And I am not one to discourage coding on the real thing

Coding for PAL in America could surprise some sceners here in a good way I think

If anything it would show that there is new blood (or an old fan of the demoscene anyway) ready to get serious about learning to code on a new arch and chipset. I know that when I see someone else do something it often fuels the fire of activity in myself as well.

-Brett

[Vortex]

Originally Posted by Plagueis/KRX

So I want to join in the fun with you guys...where the action is going on...Sweden, Germany, UK, Poland, lots of people who make the time to code and pixel, and make cool tunes.

Hey don't forget about the Nethervoids... Loads of people writing demo's there, so far I found 1..

Originally Posted by Plagueis/KRX

And as far as OCS...it's the Amiga I bought in 1988 and enjoyed until 1992 (when a power surge killed it).

Urgh, sounds familiar

Originally Posted by Plagueis/KRX

If anything it would show that there is new blood (or an old fan of the demoscene anyway) ready to get serious about learning to code on a new arch and chipset. I know that when I see someone else do something it often fuels the fire of activity in myself as well.

-Brett

Great, the more the merrier \o/.

[pmc]

Originally Posted by Photon

NTSC or PAL, well there's not many doing OCS stuff on either platform at the moment

This is very true and, I think, quite depressing. What's wrong with old skool Amigas for demo prods?

They don't even seem to have a separate A500 section at parties - you have to make your A500 prod run on the compo A1200. That's still cheating though to my mind - even though you might not be using AGA graphics modes your demo is still more than likely running on a 68060 on one of those machines so you're not showing off that your prod runs like a dream on a vanilla 68000 Amiga. I think I remember reading something somewhere from Breakpoint saying that if the A500 demo didn't work on the compo A1200 it could still be entered in the console competition.

Personally I would include ECS machines in with the OCS ones in terms of being proper old skool Amigas (yes Photon I know this means I should be hunted down as a traitor! ) and I think more stuff should be made for these Amiga platforms.

I would like to understand and code some of the A1200 style demo effects in the future and I love lots of AGA demos but my heart is still truly with the original demo stuff I saw as a kid.

I say keep it Retro!

Originally Posted by Plagueis/KRX

perhaps I have an ECS Agnus only and not a full ECS. Isn't there such an A500? Back in my Amiga "prime", there was only the OCS A500, 2000, and 1000.

I think that's correct - A500 with ECS Agnus only - fatter Agnus was it called...?

Originally Posted by Photon

Cycle Exact is pretty accurate but not perfect.

Hopefully this will get even better though - hasn't Toni gone super accurate with cycle exact timing for OCS / ECS machines in the upcoming WinUAE release...?

Originally Posted by Photon

And I am not one to discourage coding on the real thing

Definitely not. Vortex does all his stuff on the native machine - he *really* keeps it real.

From a practical standpoint I agree too - even if you code in the emulator the stuff *must* be tested on the real deal prior to release.

I've had this experience myself recently - my vector demo part looks perfect in WinUAE but suffers occasional graphics glitches in one of the objects when running on the real thing.

Toni's doing some testing to see if he can see why the emu and the real thing differ on it at the moment...

[Plagueis/KRX]

Originally Posted by pmc

They don't even seem to have a separate A500 section at parties - you have to make your A500 prod run on the compo A1200.

That's a pity. Since it's not fully compatible, and is truly significantly different hardware wise, the A500 ought to have it's own section. Of course, if there were (or once there has become) enough coders making strictly "old school" A500 demos, the organizers would have no choice but to add such a section. A possible motivator for people with our kind of interest.

Originally Posted by pmc

That's still cheating though to my mind - even though you might not be using AGA graphics modes your demo is still more than likely running on a 68060 on one of those machines so you're not showing off that your prod runs like a dream on a vanilla 68000 Amiga. I think I remember reading something somewhere from Breakpoint saying that if the A500 demo didn't work on the compo A1200 it could still be entered in the console competition.

Yes! Exactly...but I guess I am so far from being able to attend compos like Breakpoint any time soon that it's not much of a concern to me. What's more of a concern is what's best for the future of demo coding and building up the community...so we'll have more people interested in showing off cool effects and challenging their mind with interesting low-level coding quandaries....long into the future. I mean me personally, as long as I have at least one other person who will communicate with me regularly and code along with me, I'm happy. A handful of people to talk about code, design and effects with is enough, but yeah, the more the merrier!

Originally Posted by pmc

Personally I would include ECS machines in with the OCS ones in terms of being proper old skool Amigas (yes Photon I know this means I should be hunted down as a traitor! ) and I think more stuff should be made for these Amiga platforms.

If I were designing an exclusively Amiga demo scene oriented website (too bad that doesn't exist!) I would personally want there to be an A500 demo section on such a web-bbs, with two subdivisions below that root (OCS and ECS). I think they ought to be separated, since in my experience, even between two A500's without the "+", everything is *not* compatible.

Originally Posted by pmc

I would like to understand and code some of the A1200 style demo effects in the future and I love lots of AGA demos but my heart is still truly with the original demo stuff I saw as a kid.

My heart is in the same place as yours, especially since I know it will probably take me a year or two to even release a few small demos (esp. since I code on other platforms simultaneously..plus play around with cracking for fun)

Originally Posted by pmc

I think that's correct - A500 with ECS Agnus only - fatter Agnus was it called...?

Yes, but how do I verifiy this for sure? Is there a serial number chart, or perhaps some code I can run that will probe the hardware to perform the test. How do you tell an Amiga 500+? Is it written on it somewhere. I wasn't able to find any on ebay the other day.

Originally Posted by pmc

From a practical standpoint I agree too - even if you code in the emulator the stuff *must* be tested on the real deal prior to release.

Even from a philosophical standpoint. Think about it...if you are coding on an emulator you aren't actually coding on the machine...you are coding on a meta-machine. If you coded on a a Sparc station with a PC emu, running WinUAE, you'd be coding on a meta-meta-machine. Eventually you are so far from the real hardware you might forget what you're doing. An emulator is a great tool, and now that we're grown up with lives, wives, etc...it really speeds up development time. It's a great thing. But there's been people who've coded demos I've seen (on the 64) entirely in the emu. They didn't even notice when the stuff didn't work on the actual computer. One big thing demos are about is total control over the hardware. How can you ensure that if you don't even have the real hardware in your shop? Anyway that's my two pounds.

-Brett

[pmc]

Originally Posted by Plagueis/KRX

with two subdivisions below that root (OCS and ECS). I think they ought to be separated, since in my experience, even between two A500's without the "+", everything is *not* compatible.

They're the same if you don't use ECS only functions of the custom chips cos they both run standard 68000 processors and to be honest things like bigger blits (ECS only function) are very rarely used - if ever. Most of the incompatibility (someone correct me if I'm wrong...) is more likely due to bad coding practice from whatever guy made the OCS version than anything to do with incompatibilities running OCS software on ECS machines.

Originally Posted by Plagueis/KRX

Yes, but how do I verifiy this for sure? Is there a serial number chart, or perhaps some code I can run that will probe the hardware to perform the test. How do you tell an Amiga 500+? Is it written on it somewhere. I wasn't able to find any on ebay the other day.

Far as I know A500+ would be written on it - just like on my A500+. By the way, that's why I code ECS A500+ in WinUAE cos I still have one of the real machines whereas I don't own an OCS A500.

As to how you could tell whether you have a fat or fatter Agnus chip in your A500 I'm not sure. You could look inside - one of the hardware gurus could tell you what to look for.

Alternatively, maybe there's a software check you can do just like you can to ascertain what processor the host Amiga is running. One of the software gurus could probably tell you this.

Or you could always ask the guru's guru Toni - he'll know for sure.

[absence]

Originally Posted by pmc

As to how you could tell whether you have a fat or fatter Agnus chip in your A500 I'm not sure. You could look inside - one of the hardware gurus could tell you what to look for.

Not sure how reliable it is, but I seem to recall that red and green LEDs means OCS Agnus, and green and yellow LEDs means ECS Agnus.

[Plagueis/KRX]

Originally Posted by absence

Not sure how reliable it is, but I seem to recall that red and green LEDs means OCS Agnus, and green and yellow LEDs means ECS Agnus.

Absence,

If that's reliable then my 2nd Amiga here is definitely an ECS Agnus, as I suspected.

@PMC: I did not know that the "+" was written on it. Ok, that makes things easy with the plus. heh.

[MagerValp]

Originally Posted by pmc

This is very true and, I think, quite depressing. What's wrong with old skool Amigas for demo prods?

They don't even seem to have a separate A500 section at parties - you have to make your A500 prod run on the compo A1200.

I'd just like to point out that at Datastorm there will be a 1MB A500 compo machine, and if there are enough A500 entries they'll get their own section, separate from the A1200/060.

[pmc]

@ MagerValp - \o/

Nice one for letting me know that - I didn't realise!

Really good news!

[Plagueis/KRX]

Originally Posted by MagerValp

I'd just like to point out that at Datastorm there will be a 1MB A500 compo machine, and if there are enough A500 entries they'll get their own section, separate from the A1200/060.

Yeah, nice...thanks! I guess you are the same "MagerValp" of c64 Ultima IV Gold fame?? Greets!

-Darth Plagueis/KRX/FOE/ATA

Edit: I just saw the link to your paradroid site. So it is you. cool.

[Photon]

Originally Posted by pmc

Personally I would include ECS machines in with the OCS ones in terms of being proper old skool Amigas (yes Photon I know this means I should be hunted down as a traitor! ) and I think more stuff should be made for these Amiga platforms.

Traitor? Nah... it's more about "being runnable" than about a specific platform for me. I'm in A500 mode at the moment, but I think coders should make all kinds of demos for all kinds of Amiga models, the more the merrier

A500 with extra 512k slow or A500+ or A600 doesn't really matter, basically the same stuff is possible. A500 with 512k chip only can be a bit of a hassle.

The 'hassle' is that with a few screen buffers and a good Soundtracker module, you can pretty much forget about adding a Divide table or other things to make certain effects possible. Because the OS will have used a huge chunk of the 512k, so if you want it to exit to CLI again... You can disallow exit to CLI ofc, or make a trackmo. Or use a tiny chipmusic tune, or load demoparts separately ('Dosmo'? ).

[Leffmann]

I think a lot of people forget to make good use of the memory too, like reusing memory when it's not needed anymore, instead of the lazy approach and just allocate enough memory to hold all demo parts in their entirety in memory at once.

Another thing to think of is to split sections up to avoid problems with fragmented memory. 300k of contiguous RAM might not be found, but if you split your bitplanes, pictures etc. up into 6x 50k sections or whatever it's more likely they'll fit somewhere.

BSS space in code and data sections can be useful too, if you for some reason won't be crunching your program.

[pmc]

@ Leffman - I always used to use multiple sections in my code but recently with the megademo parts I've used single large code_c sections as the code / data all has to be strictly pc relative for the trackloader.

Now, I've always been told that if possible, using pc relative code is desirable but obviously this doesn't work across sections.

Have you got any advice for a nice compromise? - ie. strategies for using multiple sections but still using as much pc relative code as possible?