
INSTRUCTION SET
S3C8248/C8245/P8245/C8247/C8249/P8249
6-30
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; cleared otherwise.
D:
Unaffected.
H:
Unaffected.
Format:
Bytes
Cycles
Opcode
(Hex)
Addr Mode
dst src
opc
dst |
src
2
4
A2
r
r
6
A3
r
lr
opc
src
dst
3
6
A4
R
R
6
A5
R
IR
opc
dst
src
3
6
A6
R
IM
Examples:
1.
Given: R1 = 02H and R2 = 03H:
CP
R1,R2
→
Set the C and S flags
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:
CP
R1,R2
JP
UGE,SKIP
INC
R1
SKIP
LD
R3,R1
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.
Summary of Contents for C8245
Page 31: ...ADDRESS SPACES S3C8248 C8245 P8245 C8247 C8249 P8249 2 20 NOTES ...
Page 107: ...INTERRUPT STRUCTURE S3C8248 C8245 P8245 C8247 C8249 P8249 5 18 NOTES ...
Page 195: ...INSTRUCTION SET S3C8248 C8245 P8245 C8247 C8249 P8249 6 88 NOTES ...
Page 221: ...I O PORTS S3C8248 C8245 P8245 C8247 C8249 P8249 9 16 NOTES ...
Page 245: ...16 BIT TIMER 0 1 S3C8248 C8245 P8245 C8247 C8249 P8249 12 10 NOTES ...
Page 249: ...WATCH TIMER S3C8248 C8245 P8245 C8247 C8249 P8249 13 4 NOTES ...
Page 267: ...A D CONVERTER S3C8248 C8245 P8245 C8247 C8249 P8249 15 6 NOTES ...
Page 299: ...S3P8245 P8249 OTP S3C8248 C8245 P8245 C8247 C8249 P8249 21 8 NOTES ...
Page 307: ......
Page 309: ......
Page 311: ......
Page 313: ......