nsc800 National Semiconductor Corporation, nsc800 Datasheet - Page 57

• Manufacturer Part Number: nsc800
• Description: Nsc800tm High-performance Low-power Cmos Microprocessor
• Manufacturer: National Semiconductor Corporation

12 14 Program Control
RETN
Unconditional return from non-maskable interrupt handling
subroutine Functionally similar to RET instruction except
interrupt enable state is restored to that prior to non-mask-
able interrupt
PC
PC
SP
IFF
Timing
Addressing Mode
7
1
0
L
H
1
6
1
1
SP
5
1
0
(SP)
(SP
IFF
a
4
0
0
2
a
2
3
1
0
1)
2
1
1
1
0
0
0
1
1
No flags affected
M cycles
T states
Register Indirect
(Continued)
14 (4 4 3 3)
4
57
RESTARTS
RST
The present contents of the PC are pushed onto the memo-
ry stack and the PC is loaded with dedicated program loca-
tions as determined by the specific restart executed
(SP
(SP
SP
PC
PC
Timing
Addressing Mode
p
t
H
L
b
b
00H
000
1)
2)
SP
P
P
0
08H
b
001
PC
PC
2
7
1
H
L
10H
010
6
1
5
18H
011
No flags affected
M cycles
T states
Modified Page Zero
4
t
3
20H
100
2
1
28H
101
1
1
11 (5 3 3)
3
0
1
30H
110
38H
111