1989_MELPS_7700_Software_Manual

PLA
Pull Accumulator A from Stack
PLA
Operation
If m=O,
S ~ S + 1
AL ~ M(S)
S ~ S + 1
AH ~ M(S)
If m=1,
S ~ S + 1
AL ~ M(S)
Description
The stack pointer S is incremented, and then restores the lower byte of the
accumulator A with the data at the address indicated by the stack pointer S.
Again, increments the stack pointer S and then restores the upper byte of the accumulator
A with the data at the address indicated by the stack pointer S. When
the data length selection flag m is set to 0, 2 bytes data are restored. When the
data length selection flag m is set to 1, only 1 byte data is restored (to the lower
byte of the accumulator A).
Status flags
IPL:
N
v
m
x
o
I
Z
C
Not affected .
. Set to 1 when bit 15 (or bit 7 if the data length selection flag m is set to 1) of the
operation result is 1. Otherwise, cleared to O.
Not affected.
Not affected.
Not affected.
Not affected.
Not affected.
Set to 1 when the result of operation is O. Otherwise, cleared to O.
Not affected.
Addressing mode I Syntax Machine code Bytes Cycles
Stack I PLA 6816 1 5
116