How does AAA instruction work in 8086?
How does AAA instruction work in 8086?
➢ AAA Instruction – AAA converts the result of the addition of two valid unpacked BCD digits to a valid 2-digit BCD number and takes the AL register as its implicit operand. Two operands of the addition must have its lower 4 bits contain a number in the range from 0-9.
What is the use of AAA instruction?
AAA–ASCII Adjust After Addition The AAA instruction is only useful when it follows an ADD instruction that adds (binary addition) two unpacked BCD values and stores a byte result in the AL register. The AAA instruction then adjusts the contents of the AL register to contain the correct 1-digit unpacked BCD result.
How many operations are there for AAA instruction?
The ASCII arithmetic instruction function with ASCII-coded numbers. These numbers range in value from 30H to 39H for the numbers 0 to 9. There are four instructions used with ASCII arithmetic operations: AAA (ASCII Adjust after Addition)
What is the source of operand and destination operand for instruction AAA Mcq?
Explanation: AAA is a mnemonic. It doesn’t have either a source or destination operand. Explanation: The AAD instruction converts two unpacked BCD digits in AH and AL to the equivalent binary number in AL. This adjustment must be made before dividing the two unpacked BCD digits.
What are the 8086 instruction used for BCD arithmetic?
Arithmetic Instructions
| Instruction | Description |
|---|---|
| IDIV | Signed 8-bit or 16-bit division. |
| INC | Increment Register or memory by 1. |
| DEC | Decrement register or memory by 1. |
| DAA | Decimal Adjust after BCD Addition: When two BCD numbers are added, the DAA is used after ADD or ADC instruction to get correct answer in BCD. |
What is the source operand and destination operand for instruction AAA Mcq?
Explanation: The source operand is the element which is data or data stored memory location on which operation is performed. Explanation: Since the destination should be able to store the data, immediate data cannot be considered as a destination operand. Explanation: AAA is a mnemonic.
What is ADC in assembly language?
The ADC (Add with Carry) instruction adds the values in Rn and Operand2 , together with the carry flag. You can use ADC to synthesize multiword arithmetic. In certain circumstances, the assembler can substitute one instruction for another.
What is ascii adjust after addition?
AAA (ASCII Adjust after Addition) changes the contents of register AL to a valid unpacked decimal number, and zeros the top 4 bits. AAA must always follow the addition of two unpacked decimal operands in AL. The carry flag is set and AH is incremented if a carry is necessary.
What are the followings instructions contains of an 8086?
Arithmetic Instructions
| Instruction | Description |
|---|---|
| ADC | Adds specified operands and the carry status (i.e. carry of the previous stage). |
| SUB | Subtract immediate data from accumulator, memory or register. |
| SBB | Subtract immediate data with borrow from accumulator, memory or register. |
| MUL | Unsigned 8-bit or 16-bit multiplication. |
How does AAA work in 8086 instruction set?
– Stack Overflow how does AAA work in 8086 instruction set? if low nibble of AL > 9 or AF = 1 then: AL = AL + 6 AH = AH + 1 AF = 1 CF = 1 else AF = 0 CF = 0 in both cases: clear the high nibble of AL. Example: MOV AX, 15 ; AH = 00, AL = 0Fh AAA ; AH = 01, AL = 05 RET
What is the AAA instruction used for in C?
The aaa instruction is mainly useful for adding strings of digits where there is exactly one decimal digit per byte in a string of numbers. This text will not deal with BCD or ASCII numeric strings, so you can safely ignore this instruction for now.
What is ax=0205h on 8088 and 80386?
If AX contains OOFFh, executing AAA on an 8088 will leave AX=0105h. On an 80386, the same operation will leave AX=0205h. Despite the different implementation, this instruction does operate as intended for all valid operands.
What are the instruction sets of 8086 microprocessor?
Microprocessor – 8086 Instruction Sets 1 Data Transfer Instructions 2 Arithmetic Instructions 3 Bit Manipulation Instructions 4 String Instructions 5 Program Execution Transfer Instructions (Branch & Loop Instructions) 6 Processor Control Instructions 7 Iteration Control Instructions 8 Interrupt Instructions
