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S3C9454B/F9454B
SAM88RCRI INSTRUCTION SET
6-47
SUB
— Subtract
SUB
dst,src
Operation:
dst
←
dst – src
The source operand is subtracted from the destination operand and the result is stored in the
destination. The contents of the source are unaffected. Subtraction is performed by adding the
two's complement of the source operand to the destination operand.
Flags:
C:
Set if a "borrow" occurred; 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:
Bytes
Cycles
Opcode
(Hex)
Addr Mode
dst src
opc
dst | src
2
4
22
r
r
6
23
r
lr
opc
src
dst
3
6
24
R
R
6
25
R
IR
opc
dst
src
3
6
26
R
IM
Examples:
Given: R1 = 12H, R2 = 03H, register 01H = 21H, register 02H = 03H, register 03H = 0AH:
SUB
R1,R2
→
R1 = 0FH, R2 = 03H
SUB
R1,@R2
→
R1 = 08H, R2 = 03H
SUB
01H,02H
→
Register 01H = 1EH, register 02H = 03H
SUB
01H,@02H
→
Register 01H = 17H, register 02H = 03H
SUB
01H,#90H
→
Register 01H = 91H; C, S, and V = "1"
SUB
01H,#65H
→
Register 01H = 0BCH; C and S = "1", V = "0"
In the first example, if working register R1 contains the value 12H and if register R2 contains the
value 03H, the statement "SUB R1,R2" subtracts the source value (03H) from the destination
value (12H) and stores the result (0FH) in destination register R1.
Summary of Contents for S3C9454B
Page 1: ...S3C9454B F9454B 8 BIT CMOS MICROCONTROLLER USER S MANUAL Revision 1 ...
Page 25: ...PRODUCT OVERVIEW S3C9454B F9454B 1 10 NOTES ...
Page 35: ...ADDRESS SPACES S3C9454B F9454B 2 10 NOTES ...
Page 65: ...CONTROL REGISTERS S3C9454B F9454B 4 18 NOTES ...
Page 123: ...CLOCK CIRCUIT S3C9454B F9454B 7 4 NOTES ...
Page 133: ...RESET and POWER DOWN S39454B F9454B 8 10 NOTES ...
Page 145: ...I O PORTS S3C9454B F9454B 9 12 NOTES ...
Page 173: ...A D CONVERTER S3C9454B F9454B 12 8 NOTES ...
Page 183: ...ELECTRICAL DATA S3C9454B F9454B 13 10 NOTES ...