ZiLOG Z8 Series User Manual page 222

PUSH
Syntax
PUSH src
Instruction Format
OPC
Operation
SP ← SP–1
@SP ← src
The contents of the SP (stack pointer) are decremented by one, then the contents of the
source operand are loaded into the location addressed by the decremented SP, thus adding
a new element to the stack.
Flag
C
Z
S
V
D
H
Note: Address modes R or IR can be used to specify a 4-bit Working Register. In this format, the
destination Working Register operand is specified by adding
of the operand. For example, if Working Register R12 (CH) is the destination operand, then
is used as the destination operand in the Op Code.
ECh
E
Example 1
If the SP contains
PUSH FCh
Op Code: 70 FC
stores the contents of Register
operation, the SP contains
UM001604-0108
Cycles
10 Internal Stack
12 External Stack
src
10 Internal Stack
10 External Stack
Description
Unaffected
Unaffected
Unaffected
Unaffected
Unaffected
Unaffected
dst
, the statement:
1001h
FCh
1000h
OPC Address Mode
(Hex)
70
71
(the Flag Register) in location
.
®
Z8
User Manual
dst
R
IR
( ) to the high nibble
1110b Eh
. After the PUSH
1000h
Instruction Description
CPU
215