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INSTRUCTION SET
IN
A,PO
I"puto'
Port 0 Data
to
Accumulator (8021, 8022 Only)
Same
as
INS A,BUS except no
RD
pulse generated.
INS A,BUS Strobed I"put
of
BUS Data to Accumulator
10000110001
This
is
a 2-cycle instruction. Data present on the
BUS port
is
transferred (read) to the accumulator
when the
RD
pulse
is
dropped. (Refer to section on
programming memory expansion for
details).
(A)
__
(BUS)
Example: INPBUS: INS A,BUS ;INPUT BUS CONTENTS
;TO ACC
JBb
address
Jump
If
Accumulator Bit
is
Set
(Not in 8021, 8022)
I
b2
b1
bo
1 I 0 0 1 0 I 1
a7
a6
as
a4
I
a3 a2
a1
aO
I
This
is
a 2-cycle instruction. Control passes to the
specified address if
accumulator bit 'b'
is
set
to one. b=0-7
(PCO-7)-- addr
(PC) = (PC)+2
Example: JB4IS1: JB4 NEXT
If
Bb=1
If
Bb=O
;JUMP TO 'NEXT' ROUTINE
;IF ACC BIT
4=1
JC
address
Jump If Carry
Is
Set
11
1 1 1 1 0 1 1 0 1 I
a7
a6
as
a4
I
a3 a2
a1
aO
I
This
is
a 2-cycle instruction. Control passes to the
specified address if the carry bit
is
set to one.
(PCO-7)-- addr
(PC) = (PC)+2
Example: JC1: JC OVFLOW
If
C=1
If
C=O
;JUMP TO 'OVFLOW' ROUTINE
;IF
C=1
JFO
address
Jump If
Flag
Ols
Set
(Not in 8021, 8022)
11
0 1 1 1 0 1 1 0 1
~
a6
as
a4
I
a3 a2
a1
ao
I
This
is
a 2-cycle instruction. Control passes to the
specified address if
flag 0
is
set to one.
(PCO-7)-- addr If
FO=1
(PC) = (PC)+2 If
FO=O
Example:
JFOIS1:
JFO
TOTAL
Mnemonics copyright Intel Corporation
1976.
;JUMP TO 'TOTAL' ROUTINE
;IF
FO=1
4·18