What is AH and AL in assembly language?
The least significant byte of AX can be used as a single 8-bit register called AL, while the most significant byte of AX can be used as a single 8-bit register called AH. These names refer to the same physical register. When referring to registers in assembly language, the names are not case-sensitive.
What is the AX register?
AX is the primary accumulator; it is used in input/output and most arithmetic instructions. For example, in multiplication operation, one operand is stored in EAX or AX or AL register according to the size of the operand. BX is known as the base register, as it could be used in indexed addressing.
Which register is Al?
al and ah are the 8-bit, “char” size registers. al is the low 8 bits, ah is the high 8 bits.
What is test Al Al?
The test al,al is a bitwise AND operation between al and itself. If al & al == 0, the zero flag will be set to 1. je (or jz ) instruction will jump to the address of label , if the zero flag is 1.
What does EAX stand for?
EAX
Acronym | Definition |
---|---|
EAX | Environment Audio Extension |
EAX | Environmental Audio Extensions |
EAX | Electronic Automatic Exchange |
EAX | Environmental Audio Experience |
What is Al in EAX?
EAX is the full 32-bit value AX is the lower 16-bits AL is the lower 8 bits AH is the bits 8 through 15 (zero-based)
What is test EAX EAX?
Anding a value with itself gives the same value, so test eax, eax sets the flags based on whatever eax contains. ZF is set when the result of an operation is zero. jne jumps when ZF is not set. So the jump will be taken when strcmp returns nonzero, meaning the strings are unequal.
What is EAX register used for?
EAX,AX,AH,AL : Called the Accumulator register. It is used for I/O port access, arithmetic, interrupt calls, etc…
What is the origin of AX register?
The X in AX meant to be a placeholder that stood for both H and L . This is in a way similar to how much later the “x” in x86 was meant to refer to 8086, 80186, 80286, etc. Since 8008 had seven 8-bit registers, they could be mapped well to the eight 8086 registers, with one to spare.
What are the three types of registers?
Different Types of Registers
- MAR Register. The full form of MAR is the memory address register.
- MDR. The full form of MDR register is a memory data register.
- MBR. The full form of MBR is the memory buffer register.
- PC. The full form of PC is the program counter register.
- Accumulator.
- Index Register.
- Instruction Register.
When was the AX register added to the CPU?
ax is the 16-bit, “short” size register. It was added in 1979with the 8086 CPU, but is used in DOS or BIOS code to this day. al and ah are the 8-bit, “char” size registers. al is the low 8 bits, ah is the high 8 bits. They’re pretty similar to the old 8-bit registers of the 8008 back in1972.
What are the four registers in the ah al system?
The four general purpose registers are the AX, BX, CX, and DX registers. AX – accumulator, and preferred for most operations. BX – base register, typically used to hold the address of a procedure or variable. CX – count register, typically used for looping. DX – data register, typically used for multiplication and division.
What is the difference between Al and Ah?
al and ah are the 8-bit, “char” size registers. the low 8 bits, ah is the high 8 bits. They’re pretty similar to the old 8-bit registers of the 8008 back in1972.
How to map Ax, ah, al map onto EAX?
1 EAX – Full 32 bit value 2 AX – lower 16 bit value 3 AH – Bits from 8 to 15 4 AL – lower 8 bits of EAX/AX