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S3C8248/C8245/P8245/C8247/C8249/P8249
ADD
— Add
ADD
dst,src
dst ← dst + src
Operation:
The source operand is added to the destination operand and the sum is stored in the destination.
The contents of the source are unaffected. Two's-complement addition is performed.
Flags:
C: Set if there is a carry from the most significant bit of the result; 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 both operands are of the same sign and the
result is of the opposite sign; cleared otherwise.
D: Always cleared to "0".
H: Set if a carry from the low-order nibble occurred.
Format:
opc
opc
opc
Examples:
Given: R1 = 12H, R2 = 03H, register 01H = 21H, register 02H = 03H, register 03H = 0AH:
ADD
ADD
ADD
ADD
ADD
In the first example, destination working register R1 contains 12H and the source working
register R2 contains 03H. The statement "ADD R1,R2" adds 03H to 12H, leaving the value 15H
in register R1.
dst | src
src
dst
dst
src
→
R1,R2
→
R1,@R2
→
01H,02H
→
01H,@02H
→
01H,#25H
Bytes
2
3
3
R1 = 15H, R2 = 03H
R1 = 1CH, R2 = 03H
Register 01H = 24H, register 02H = 03H
Register 01H = 2BH, register 02H = 03H
Register 01H = 46H
INSTRUCTION SET
Cycles
Opcode
(Hex)
4
02
6
03
6
04
6
05
6
06
Addr Mode
dst
src
r
r
r
lr
R
R
R
IR
R
IM
6-15
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