search

chipsalliance / rocket-chip

Rocket Chip Generator
Other
3.24k stars 1.13k forks source link

How can I reduce Rocket Chip DRAM size from 256MB ? #2690

Closed Uzair540 closed 3 years ago

Uzair540 commented 4 years ago

I am having integer overflow error because of the large 256MB size of DRAM. issue ram I want to map rocketchip generated SOC on my FPGA Arty A7-35.When I map this I got overflow integer error due to the large size of RAM issue 3

I am using 64kb data and instruction cache I want to reduce RAM size of rocket chip. From where in scala /Chisel file I can make changes? Line 224 gives me an error of integer flow which means my DRAM size is very large 256MB.How can I change my RAM size from my scala code Can you elaborate me the path ? @aswaterman @yunsup

aswaterman commented 4 years ago

https://github.com/chipsalliance/rocket-chip/blob/630600d860a0ff0ec1e290931d301cc6f2b96fe0/src/main/scala/subsystem/Configs.scala#L392

Uzair540 commented 4 years ago

@aswaterman can you please elaborate what kind of information this variable is giving about the size of RAM,How many address bits are there and width of the memory?

aswaterman commented 4 years ago

That's the number of bytes in the main memory. Reducing that number will reduce the number of rows in the RAM.

Uzair540 commented 3 years ago

thanks I got your point