ZiLOG Z8 Technical Manual page 53

DI
Instruction for.at:
OPC
Operation:
flags:
EX8lllple:
IMR (7)
<--
0
01
Disable Interrupts
OPC
Cycles (Hex)
6 8F
Bit 7
of control register 251 (the Interrupt Mask Register) is reset to
O. All
interrupts are disabled, although they remain potentially enabled (i.e., the Global
Interrupt Enable is cleared--not the individual interrupt level enables.)
No flags affected
If control register 251 contains
%8A
(10001010, that is, interrupts IRQ1 and IRQ3 are
enabled), the statement
DI
sets control register 251 to
%OA
and disables these interrupts.
5-19