The DAA (Decimal Adjust after Addition) instruction allows addition of numbers represented in 8-bit packed BCD code . It is used immediately after normal addition instruction operating on BCD codes. This instruction assumes the AL register as the source and the destination, and hence it requires no operand.
What happens when DAA instructions is executed?
The DAA instruction then adjusts the contents of the AL register to contain the correct 2-digit, packed BCD result . If a decimal carry is detected, the CF and AF flags are set accordingly. This instruction executes as described above in compatibility mode and legacy mode.
How do you handle DAA instruction show with an example?
All that is required to be done is to add the BCD numbers and store the result in A , and then execute the DAA instruction. If the LS hex digit in A is <= 9 and AC flag is 0, the LS hex digit value will not be altered. If the LS hex digit is >9, or if AC flag is set to 1, it adds 6 to the LS hex digit of A.
What are the flags affected due to DAA instruction?
What are the flags affected due to DAA instructions? Flags Affected ¶ The CF and AF flags are set if the adjustment of the value results in a decimal carry in either digit of the result (see the “Operation” section above). The SF, ZF, and PF flags are set according to the result.
What is DAA in 8051?
The DA instruction adjusts the eight-bit value in the Accumulator resulting from the earlier addition of two variables (each in packed-BCD format), producing two four-bit digits. Any ADD or ADDC instruction may have been used to perform the addition. All of this occurs during the one instruction cycle. ...
What is the purpose of DAA?
The DAA (Decimal Adjust after Addition) instruction allows addition of numbers represented in 8-bit packed BCD code . It is used immediately after normal addition instruction operating on BCD codes. This instruction assumes the AL register as the source and the destination, and hence it requires no operand.
What is the full form of DAA?
| Full Form Category Term | Data Access Arrangement Computer and Networking DAA | DATIA Indian Railway Station DAA | Data Availability Acknowledgment Space Science DAA | Fort Belvoir (va) Airport Code DAA |
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What are the flags of 8085?
- Carry flag (Cy),
- Auxiliary carry flag (AC),
- Sign flag (S),
- Parity flag (P), and.
- Zero flag (Z).
When a word operand is multiplied with ax the result is stored in which register?
The multiplicand should be in the AX register , and the multiplier is a word in memory or another register. For example, for an instruction like MUL DX, you must store the multiplier in DX and the multiplicand in AX. The resultant product is a doubleword, which will need two registers.
What is the use of Dad B instruction?
Though it is an arithmetic instruction , by design, flags other than Cy, will not get affected by the execution of this instruction DAD rp. Let us consider DAD B is a sample instruction of this category. As It is 1-Byte instruction so it occupies a single Byte place in the memory.
What is Xchg instruction?
In 8085 Instruction set, there is one mnemonic XCHG, which stands for eXCHanGe . This is an instruction to exchange contents of HL register pair with DE register pair. This instruction uses implied addressing mode. As it is1-Byte instruction, so It occupies only 1-Byte in the memory.
What is BCD number?
In computing and electronic systems, binary-coded decimal (BCD) is a class of binary encodings of decimal numbers where each digit is represented by a fixed number of bits , usually four or eight. Sometimes, special bit patterns are used for a sign or other indications (e.g. error or overflow).
How do you do BCD addition?
- Input: A = 12, B = 20.
- Output: 110010.
- Explanation: The summation of A and B is 12 + 20 = 32. The binary representation of 3 = 0011. The binary representation of 2 = 0010. Therefore, the BCD Addition is “0011” + “0010” = “110010”
What is CJNE?
The CJNE instruction compares the first two operands and branches to the specified destination if their values are not equal . If the values are the same, execution continues with the next instruction.
What is AJMP?
The AJMP instruction transfers program execution to the specified address . The address is formed by combining the 5 high-order bits of the address of the following instruction (for A15-A11), the 3 high-order bits of the opcode (for A10-A8), and the second byte of the instruction (for A7-A0).
What is LDA microprocessor?
In 8085 Instruction set, LDA is a mnemonic that stands for LoaD Accumulator with the contents from memory . In this instructionAccumulatorwill get initialized with 8-bit content from the 16-bit memory address as indicated in the instruction as a16. This instruction uses absolute addressing for specifying the data.
