minimig playing on it

[alexh]

Out of interest, has anyone else seen that several MiniMig screenshots show 1Mbyte of chip RAM and 512kbytes of fast ram?

I thought that it was the other way around.

And it's not only me.

http://en.wikipedia.org/wiki/Minimig

Not that it really matters.

Just wondering if it really does have that much chipram, or if a chip ID value was wrong or something leading to wrong values.

[alexh]

The kickstart lives at the address where it lives, it is in neither. It's not like the MAPROM feature of certain accelerators where it is copied to RAM to speed up access.

If you are asking if it is configurable to select from

512k chip / 1024k fast
1024k chip / 512k fast

I dont think so, not yet, and I dont know if it is even worth having that option.

[alexh]

tonyyeb wrote:
How does the 2mb of RAM on the board get allocated into fast and chip at the moment?

It is hard coded in the MiniMig verilog source.

Looking at the source code MiniMig1.v and Gary.v MiniMig has 1Mbyte of ChipRAM and 512Kbyte FastRAM

I do not think this was a valid configuration in a REAL A500 without a Fatter Agnus, but probably the Fatter Agnus had other features not yet implemented in MiniMig.

[alexh]

According to the verilog source code, ChipRAM mapped at addresses 0x000000 to 0x0FFFFF and 512Kbyte of SlowFast RAM at 0xC00000 to 0xC7FFFF.

[alexh]

I havent studied the Amiga chipset and MiniMig source code in great detail but will that extra 512Kbyte chip-ram actually get used by anything other than the CPU given the current state of the MiniMig Agnus?

The OCS agnus being only a 512Kbyte Agnus I mean.

Perhaps Dennis just had to map the 512Kbytes somewhere and that was the best place to map the RAM to?