Unit test for the branch decoder

[branylagaffe]

I want to test for the branch decoder
So that @giorgioajmone can rely on the decoder to work on a BP

Specification:

1. There shall be unit tests testing the branch decoder for each type of branch instruction. These are:
   • unconditional branch (immediate)
   • unconditional branch (register)
   • conditional branch
   • compare and branch
   • test and branch
2. There should? be unit tests for these other instruction types that are under the same "Branches, Exception Generating and System instructions" section in the ARM manual:
   • exception generation? (supervisor call, hypervisor call, etc.)
   • hints? (includes things like the pointer authentication instruction AUTIASP which is apparently used by the stress snapshot as pointed out by @BugraEryilmaz)
   • barriers? (we already have a branch_type_t enum value called QEMU_Barrier_Branch in libqflex-legacy-api.h but it is actually never used by the current branch decoder)
   • ...?

Tasks:

1. Figure what needs to be tested/ what is handled by KeenKraken
2. Write specification

[branylagaffe]

@ounuvar Please fill the [] in the description.

[ounuvar]

Should I push the current branch tests (which cover everything under Specification-1.) to the same testing branch where the load-store tests were? @branylagaffe

[branylagaffe]

Yeah thats okay

[branylagaffe]

or you can create a new branch starting form the previous testing branch, maybe with a name such as `test/decoder

[ounuvar]

Pushed them to the same testing branch