LDA

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Syntax: LDA 16-bit
Where 16-bit is for memory location.
Byte: 3byte
Addressing Mode: Direct Addressing
Working: for execution of this instruction, microprocessor will allocate first byte for opcode, second byte for lower order address and third byte for higher order.
Example: LDA 4000H 
where [4000H] = A0 H
After execution of LDA 4000H
[A]= A0 H

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SBB

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Syntax: SBB R Where R can be any of the general purpose registers (A,B,C,D,E,H andL) Byte: 1byte Addressing Mode: Register   Addressing Working:  1.  2. A= A- R-b 3.  4. Flag Example: SBB D where  [D] = 10H , [A]= 22H and [c flag]= 1 After execution of SBB  B [A] = 11H  [D] = 10H // A= A-R-b => 22-10-1 =11H Program: write an ALP for subtraction of values present in Registers A ,B and C. Where A carries 44H and B carries 30H and C carries 10H. Store result at memory location 5000H. Label  Mnemonics  Comments Start: SUB B ;  a=a - b// 44-30= 14h            SBB  C ;  a= a - c - cy... A= 14-10-0 = 4h           STA 5000H   Stop: HLT Output: [5000H]= 04H      
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