The BIT #imm instruction behaves differently from the BIT instruction with other
addressing modes, in that it does /not/ set the N and V flags according to the
value of its operand. It only sets the Z flag, in accordance to the value of
(A & operand).
This is corroborated in two ways:
- The 65x02 test suite;
- Documentation about BIT #imm such as http://www.6502.org/tutorials/65c02opcodes.html
This patch implements the correct behavior for BIT with immediate addressing.
The patched version passes the 65x02 test suite for 65C02 opcode 0x89.