Long story short, I've been hunting this bug for a while now.
While passing armwresteler tests, I still had an emulation bug which
causeed libgcc's iprintf to produce bugged strings.
In order to find it, I've used https://github.com/fleroviux/NanoboyAdvance/
And patched it to produce a formatted log of every step of the execution
of iprintf:
{OPCODE} {PC} {R0} {R1} ... {R14} {FLAGS}
Did the same on my emulator and searched for differences.
Found out the a "CMP r3, #0x0" instruction turned off the carry flag
when it shouldn't. Found this sad function, the check I'm using for
carry flag is meaningless when done on signed integers. :sigh:
Former-commit-id: 871d2581921796dae9bf4f5fdaa45c6ad46aebec
The way cycles were counted up untill now was not accurate enough,
I've avoided doing so because the instruction implementation looks
bloated this way, but I've had problems with cycle accuracy with tonc's
timer demo.
This is not entirely correct though, and I'm 100% sure there are some
mistakes, but works good enough for now.
Former-commit-id: 748faaf99fe2f42925c0a2110192c6a01e5d27d4
This commit refactors the ioregs:
* Use bitfield crate to implement the GPU ioregs.
* IoRegs are stored in their own variables bindings (i.e, Gpu related ioregs are now fields of the Gpu struct)
- This optimize performance quiet alot from my testings - since every scanline was accessing deseralizing ioregs from sysbus. (Getting constant 59fps now)
* For now, comment out DMA model
Also, cleaned the code up to eliminate rustc warnings.
Former-commit-id: 9077695c446ebd1a71783acfdd9819245aa02d7a
This fixes a bug where "swi" instructions are decoded as conditional
branches.
The order really matters here, because Swi instructions are actually
conditional branch with illegal condition code.
Former-commit-id: 0024a8b53386a510dd321c157391c99a2af29223
