Adding SLTUI instruction

[galloj]

Instruction is documented here: https://edumips64.readthedocs.io/en/latest/instructions.html but is not implemented. If I am right it should be same as SLTIU, so I basically copied how it is done in DADDUI.java.

[codecov-commenter]

Codecov Report

Merging #710 (38f4799) into master (d92aea6) will decrease coverage by 0.01%.
The diff coverage is 0.00%.

@@             Coverage Diff              @@
##             master     #710      +/-   ##
============================================
- Coverage     51.14%   51.13%   -0.02%     
  Complexity     1447     1447              
============================================
  Files           249      250       +1     
  Lines          9879     9882       +3     
  Branches       1092     1092              
============================================
  Hits           5053     5053              
- Misses         4507     4510       +3     
  Partials        319      319              

Impacted Files	Coverage Δ
...java/org/edumips64/core/is/InstructionBuilder.java	83.03% <0.00%> (-0.75%)	⬇️
src/main/java/org/edumips64/core/is/SLTUI.java	0.00% <0.00%> (ø)

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[lupino3]

Hey @galloj, thanks a lot for your contribution!

I believe that what you found is not a missing instruction, but an error in the documentation!

I cannot find an SLTUI instruction in the MIPS64 instruction set documentation: https://s3-eu-west-1.amazonaws.com/downloads-mips/documents/MIPS_Architecture_MIPS64_InstructionSet_%20AFP_P_MD00087_06.05.pdf

However, there is an SLTIU instruction, and that is what is both implemented in code (see SLTIU.java and described in the docs you pointed at.

Since I'd like to preserve a history of your contribution, would you be willing to fix the documentation, replacing the word SLTUI with the word SLTIU? If you'd prefer, I can also fix it.

Thanks again for finding and reporting this problem!

[galloj]

I wasn't really sure if it was missing instruction or error in documentation, but I chose to believe it is missing instruction because both versions of instruction can be found here in your repository: https://github.com/EduMIPS64/edumips64/blob/2b5c97e7df5c0b2a21f7d16f60eba889b5e944b1/contrib/kate_mips.xml

Also when googling for SLTUI instruction, then there are some results (although about 10 times less).

Anyways, it is likely that my guess might be wrong, so if you prefer the fix to documentation, then I will do it.

[lupino3]

Yes please! As a reference for the instructions et we follow the MIPS64 official docs I linked earlier, and there is no mention of the SLTUI instruction there.

Thank you very much!

[galloj]

Okay, new PR is opened.