|
|
|
|
|
|
by gdevic
25 days ago
|
|
|
That. I blatantly "stole" those from Z80 since they are elegant and effective. I have BF (flag) that gets set in ALU when the result is > 9, then DAA/DAS that add 6 or 10 (the latter wraps around as -6 since registers are 4-bit wide). 12'b0000_0000_001?: begin : instr_daas // DAA, DAS
if (flags[BF_BIT])
rx[0] <= rx[0] + (op_is_daa ? 4'd6 : 4'd10);
flags[CF_BIT] <= flags[BF_BIT];
state <= FETCH;
end : instr_daas
|
|
|