Coreboot does something similar to this. Very early in the boot process the RAM has not yet been initialized and so cannot be used. You need to execute some c

Coreboot does something similar to this. Very early in the boot process the RAM has not yet been initialized and so cannot be used. You need to execute some code to set up the RAM before you can use it. One approach to handling this is to write that initialization code in assembly language and make sure it only uses registers and doesn't touch any memory. But that's inconvenient. You'd much rather be able to write your code in something like C. Any C code compiled by an ordinary compiler is going to access memory (at least for the stack). Writing and maintaining a custom C compiler for this is a lot of work and still comes with a lot of limitations on the C code that it will accept. So they set up the cache in a way that it will never try to write its contents out to RAM. Then you can use the output of an ordinary C compiler that uses memory accesses and those accesses will all be served by the cache and never touch RAM. They call this "Cache as RAM". With some work you could probably boot into DOS like this. https://www.coreboot.org/data/yhlu/cache_as_ram_lb_09142006.pdf https://www.coreboot.org/data/yhlu/cache_as_ram_lb_09142006....