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SAM88RCRI INSTRUCTION SET
CP
— Compare
CP
dst,src
Operation:
dst – src
The source operand is compared to (subtracted from) the destination operand, and the
appropriate flags are set accordingly. The contents of both operands are unaffected by the
comparison.
Flags:
C:
Set if a "borrow" occurred (src > dst); cleared otherwise.
Z:
Set if the result is "0"; cleared otherwise.
S:
Set if the result is negative; cleared otherwise.
V:
Set if arithmetic overflow occurred, that is, if the operands were of opposite signs and the sign of
the result is of the same as the sign of the source operand; cleared otherwise.
Format:
opc
opc
opc
Examples:
1. Given: R1 = 02H and R2 = 03H:
Destination working register R1 contains the value 02H and source register R2 contains the
value 03H. The statement "CP R1,R2" subtracts the R2 value (source/subtrahend) from the
R1 value (destination/minuend). Because a "borrow" occurs and the difference is negative,
C and S are "1".
2. Given: R1 = 05H and R2 = 0AH:
SKIP
In this example, destination working register R1 contains the value 05H which is less than the
contents of the source working register R2 (0AH). The statement "CP R1,R2" generates C =
"1" and the JP instruction does not jump to the SKIP location. After the statement "LD R3,R1"
executes, the value 06H remains in working register R3.
6-18
dst | src
src
dst
dst
src
CP
R1,R2
CP
R1,R2
JP
UGE,SKIP
INC
R1
LD
R3,R1
Bytes
2
3
3
→
Set the C and S flags
S3C9454B/F9454B
Cycles
Opcode
(Hex)
4
A2
6
A3
6
A4
6
A5
6
A6
Addr Mode
dst
src
r
r
r
lr
R
R
R
IR
R
IM
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