More Chipram

[KThunder]

resourcefullness is a great asset. it has allowed us to do lots of things with our amigas, from accelerator projects to usb to mp3 stuff. but there are things we cant do unless we have deep finacial resources. the 8meg chipram would require a chip redesign. is it possible yeah, likely not at all.
ive never run into chip ram problems. maybe im the only amigian who has. there are lots of things you can do to get around chip ram constaints. why dont you let us know what you are trying to do and see if we can help that way. esecially before you start posting insults. (no im not from the bible belt, nor am i married to a relative)
we have all known about chip ram for a very long time, so have programmers there is a lot that can be done even with 1meg of chip ram.

[KThunder]

@leirbag
go ahead and do it. and while you are redesigning the chips put in chunky displays and true color and stuff like that. and redesign paula to have 16bit sound.
but you'll have to redesign the mobo too or have patch wires for addressing, that would be a mess.

[KThunder]

i have  questions here that are related but i dont want to start more flaming. so please... be good

what happens exactly if you just add more ram to the address area normally used by chipram. what is it detected as? fast slow or chip?

we dont really care if the custom chips can see the ram or not do we? regardless of how it does it winuae gives the emulated environment 8megs of chip ram, the emulated chips cant really use it other than to give programs use of it.

were in the memory map is the additional 6megs of chip under winuae? it is contiguous to aga chip ram right?

in other words if the cpu can see it is that enough for programs and os? what in the custom chips needs to know that "chip ram" is being used, and are there other ways of doing that. the custom chips dont manage chip ram right? the just share access to it.

[KThunder]

Zac67 wrote:


Believing that hard beyond common sense, you should really go into theology!

ok thats a bit unneccisary. he is wrong sbout an aspect of a vintage computing platform. many, many people are. i personally dont see the need for more than 2megs chip, but im not going to bash him for it.

[KThunder]

so the current custom chips dont fully decode the bus and will corrupt memory if it is above their limit. would a bus snoop chip that watches for accesses above the 2meg and inhibit action in the blitter et.al. prevent this?

[KThunder]

leirbag28 wrote:
forget all the technical stuff you know. I think what I am saying makes perfect sence to him who is willing to understand.

you can't forget the technical stuff if thats the reason it wont work. this is technical, and everything that has been done for the amiga over the last 10yrs is because of technical stuff.

[KThunder]

Piru wrote:
Can't see how it could, and even if it could, it would lack the actual blit operation that is expected to be performed.

And it's not just blitter, it's all custom hardware DMA, copper, blitter, bitplane DMA, Paula audio, floppy read/write etc etc.

what i meant was the memory not the blitter etc. if the snoop chip saw a memory access to say a memory location above 2meg, that would cause problems because of the partial decoding of the bus but the custom chips, it would basically step in and let the custom chips know not to do anything.

[KThunder]

you could easily allow normal operations to continue. anything under 2megs.

[KThunder]

the os doesnt break under winuae

[KThunder]

Piru wrote:
@KThunder

the os doesnt break under winuae

Because the WinUAE emulates chipset that works with > 2MB chip memory. WinUAE's custom chips don't ignore the uppers bits of 0x274000 pointer, but use 0x274000 as expected.

See?

thats what im saying piru.
 you use a bus snoop chip to decode the upper bits and if anything over 2meg is being accessed it lets the custom chips know

[KThunder]

Piru wrote:
And tell custom chips to do what? Don't do the operation? If they don't, the result is garbage, regardless.

Do or don't, the result is the same. Something is trashed.

yes exactly if you are trying to use above 2meg as ram you dont want the custom chips to do anything right, you want them to share the bus with the cpu. you dont need the custom chips to do anything with above 2meg do you you just want to use the ram for the cpu for programs

[KThunder]

Karlos wrote:
So you get a system with >2MB chipram that can't be used by the custom chips. It also means that things that are supposed to get done, arent, which probably means a crash. How is this useful?

noone ever said not let the custom chips do aything. everything under 2meg would be left alone by the bus snoop chip so the custom chips would continue to do their job

[KThunder]

some programs need chip memory for certain functions, amigaos loads certain things into chip ram yes. if you are trying (like some people) to run too many programs and the os needs more chip ram you are stuck. what does the custom chips in winuae use the upper parts of 8meg for? not much id wager because the os commands those chips to do stuff right. the os can use up to 8megs for lots of stuff though

why would the os allocate bitplane space up at 7meg or so? it wouldnt or wouldnt have to anyway

[KThunder]

wait... screens i see what you mean, im thinking in terms of programs but the os could put screens up there couldnt it

your stack is in chip ram, so are major parts of the os, as are any old programs and all data concerning what programs are loaded and where they are, multitasking info etc.

[KThunder]

yeah the os allocating some stuff in upper chip ram would muck stuff upp. at best it would be like slow ram or something. not completely usable, fast ram is better