Base implementation of the MMU + TLB + Exceptions #4
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Seen these come up in a couple of places, for now just log warnings for unknowns and panic for those that are known.
and implement details for status_reg
| @@ -567,7 +862,10 @@ impl Cpu { | |||
| self.ctx.tight_exit = false; | |||
| while let Some(op) = iter.next() { | |||
| self.ctx.pc += 4; | |||
| self.op(op); | |||
| match self.op(op) { | |||
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quick comment, this adds a cmp+branch on any opcode. This loop here is hot as fire, I think it's better to let the opcode implementation call exception() whenever an exception occurs, rather than propagate a Result and then having to check it for every opcode.
| @@ -88,7 +127,176 @@ pub struct CpuContext { | |||
| lines: Lines, | |||
| } | |||
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| #[derive(DeviceBE)] | |||
| pub struct RegsMI { | |||
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I don't think MI is strictly part of MIPS64. MI is a Nintendo part that handle memory mapping and it's behavior is strictly n64-related. FWIW, src/mips64 tries to be a generic MIPS interpreter, not directly related to N64.
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The MIPS Interface is part of the Reality Coprocessor.
In both the patent and an SGI presentation, the MI is referred to as the CPU interface, but it is the MI.
All the interfaces you see in these screenshots are part of the RCP.
In my emulator, I even moved the memory map definition into the RCP and connected the VR4300's SysAD reads and writes to it.
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Regarding the SysAD, I simplified the whole protocol into read and write word delegates, even though it has its own set of commands the CPU and external SysAD device (the RCP) use to communicate.
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That's fine, but this PR is adding the MI within a generic MIPS64 interpreter, not within the RCP code.
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Yep, I noticed that, hence saying it's part of the RCP.
https://github.com/rasky/r64/blob/master/src/n64.rs#L29-L35 also shows that the other RCP interfaces (and the SP/DP) are defined within the n64 struct, when they technically should be part of a rcp struct.
Sorry if I'm too pedantic :p
Based on #3
This is my first attempt at implementing these things. It's a lot of code, lots of feedback very welcome.
Correctness, unsure, my test roms are doing much more than before :)