IN
Syntax: IN 8-bit
Where 8-bit is an output port address.
Byte: 2byte
Addressing Mode: Direct Addressing
Working:
1.
2.
Example: IN 35H
Where [35H]= 20 H
After execution of above
[A] = 20H
SBB
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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