mohanson/gameboy

SUB A, r8/d8 command to set flag C

hcoderLee opened this issue · 1 comments

hcoderLee commented

According to the GBCPUman： C - Set if no borrow.
In my opinion, the code should be：

self.reg.set_flag(Flag::C, a >= n);

when the value of register A is greater then the number n, a-n is not borrowed. But in the project, the code is:

self.reg.set_flag(C, u16::from(a) < u16::from(n));

Which I couldn't understand.