Compare Decimal (Cp) - RCA 70/46 Reference Manual

Compare Decimal
(CP)
General Description
Format
(55)
Condition Code
Interrupt Action
Decimal Arithmetic
Instructions
• The operand specified by the first address (Bt/D
1 )
is algebraically
compared with the operand specified by the second address (BdD
2 ) .
The
results of the comparison determine the condition code.
The operands may be variable in length up to 16 bytes and must be in
packed format. If the fields are unequal in length, the shorter is extended
with high order zeros. If operands overlap, their rightmost byte location
must be identical.
Overflow cannot occur as a result of this operation.
F9
o
7 8 11 12 15 16 19 20 31 32 35 36 47
• 0 - the fields are numerically equal.
1 - the first operand is algebraically less than the second operand.
2 - the first operand is algebraically greater than the second operand.
• Address error:
Addressing.
Data error.
Notes •
1.
All signs and digits are checked for validity.
2. Both operands are unaltered.
3. Comparison is from right to left.
4. A positive zero compares equally
to
a negative zero.
161