Zilog Z86193 - Manual (Page 188)

Z8
®
CPU
User Manual
UM001604-0108 Instruction Description
181
Enable Interrupts
Syntax
EI
Instruction Format
Operation
IMR (7)
←
0
Bit 7 of Control Register
FBh
(the Interrupt Mask Register) is set to 1. This allows poten-
tially enabled interrupts to become enabled.
Example
If Control Register
FBh
contains
0Ah
(
00001010
) (interrupts IRQ1 and IRQ3 are
selected), the statement:
EI
Op Code: 9F
sets Control Register
FBh
to
8Ah
(
10001010b
) and enables IRQ1 and IRQ3.
Cycles
OPC
(Hex)
OPC 6 9F
Flag Description
C Unaffected
Z Unaffected
S Unaffected
V Unaffected
D Unaffected
H Unaffected