Mnemonic

Symbolic
Operation

Flags
S    Z    H    P    C

Opcode
76 543 210

Hex

Bytes

M
Cycles

Clock
Cycles

Comments

CMC

          ___
CY ¬ CY

•     •     •     •    ↕

00 111 111

3F

1

1

4

Complement
carry flag.

STC

CY ¬ 1

•     •     •     •    1

00 110 111

37

1

1

4

NOP

No Operation

•     •     •     •     •

00 000 000

00

1

1

4

HLT

CPU halted

•     •     •     •     •

01 110 110

76

1

1

4

DI¹

IFF ¬ 0

•     •     •     •     •

11 110 011

F3

1

1

4

EI¹

IFF ¬ 1

•     •     •     •     •

11 111 011

FB

1

1

4

Notes:

¹    No interrupts are issued directly after a DI or EI.
CY means the carry flag.

Flag Notation:

• = flag is not affected, 0 = flag is reset, 1 = flag is set