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8XC251SA, SB, SP, SQ USER’S MANUAL
A-14
A.3.2 Instruction Summaries
Table A-19. Summary of Add and Subtract Instructions
Add ADD <dest>,<src> dest opnd ← dest opnd + src opnd
Subtract SUB <dest>,<src> dest opnd ← dest opnd - src opnd
Add with Carry ADDC <dest>,<src> (A) ← (A) + src opnd + carry bit
Subtract with Borrow SUBB <dest>,<src> (A) ← (A) - src opnd - carry bit
Mnemonic <dest>,<src> Notes
Binary Mode Source Mode
Bytes States Bytes States
ADD
A,Rn Reg to acc 1 1 2 2
A,dir8 Dir byte to acc 2 1 (2) 2 1 (2)
A,@Ri Indir addr to acc 1 2 2 3
A,#data Immediate data to acc 2 1 2 1
ADD;
SUB
Rmd,Rms Byte reg to/from byte reg 3 2 2 1
WRjd,WRjs Word reg to/from word reg 3 3 2 2
DRkd,DRks Dword reg to/from dword reg 3 5 2 4
Rm,#data Immediate 8-bit data to/from byte reg 4 3 3 2
WRj,#data16 Immediate 16-bit data to/from word reg 5 4 4 3
DRk,#0data16 16-bit unsigned immediate data to/from
dword reg
5645
Rm,dir8 Dir addr to/from byte reg 4 3 (2) 3 2 (2)
WRj,dir8 Dir addr to/from word reg 4 4 3 3
Rm,dir16 Dir addr (64K) to/from byte reg 5 3 4 2
WRj,dir16 Dir addr (64K) to/from word reg 5 4 4 3
Rm,@WRj Indir addr (64K) to/from byte reg 4 3 3 2
Rm,@DRk Indir addr (16M) to/from byte reg 4 4 3 3
ADDC;
SUBB
A,Rn Reg to/from acc with carry 1 1 2 2
A,dir8 Dir byte to/from acc with carry 2 1 (2) 2 1 (2)
A,@Ri Indir RAM to/from acc with carry 1 2 2 3
A,#data Immediate data to/from acc with carry 2 1 2 1
NOTES:
1. A shaded cell denotes an instruction in the MCS
®
51 architecture.
2. If this instruction addresses an I/O port (P
x
,
x
= 3:0), add 1 to the number of states.