Software and Applications (non-game)
Intel 8085

What the Difference between accumulator and instruction register?


Top Answer
User Avatar
Wiki User
2009-12-15 22:12:57
2009-12-15 22:12:57

The accumulator is a general register that holds a value. It is also a special register that can be used as the target for the result of various arithmetic or logical computations. For instance, if you wanted to add two numbers, you could load the first into the accumulator, add the second to the accumulator, and then store the accumulator where wanted.

The instruction register is an internal register that holds the value of the instruction opcode in order for the 8085 to decode and process the instruction. While it is shown on the Intel block diagram for the 8085, it is not directly accessible by the running program - it is for internal use only by the 8085.

User Avatar

Related Questions

Examples: /360: no accumulator 8080: A 6800: A and B 8086: AX ...

Load instruction means to load the instruction from the memory to the processor (accumulator).. But store instruction is opposite of it,it stores information from accumulator to the memory.

In the 8085, the LDA instruction loads the accumulator from memory, while the STA instruction stores the accumulator to memory. LDA is a read, while STA is a write. LDA is opcode 3AH, while STA is opcode 32H.

Instruction decode is the process after the register fetch. Fetch--Store internal memory as register. Decode- To make sense of the instruction which has just fetched

instruction register is used to store the next instruction to be executed. instruction pointer is used to store the address of the next instruction to be executed.

There isn't any difference. Two different words forexactly same thing. Third way to call it is instruction address register.

In the 8085 microprocessor, the MOV instruction copies data between two registers, or between a register and memory. The MVI instruction differs only in that the source data is contained in the byte immediately following the opcode byte.

There is no difference between lead acid accumulator and lead acid battery.

difference between register and memory location

In the 8085, the LDA instruction loads the accumulator from memory, while the STA instructionstores the accumulator to memory. LDA is a read, while STA is a write. LDA is opcode 3AH, while STA is opcode 32H.

A register can hold data, and it can be used for temporary storage or, in the case of an accumulator, it can participate in arithmetic or logical operations. A counter is a special case of a register. Usually, it can only be loaded, stored, or incremented, or used for the stack or as the program counter.

INR increment the content of register/memory by 1and result is stored in same place. INX increment the register pair by 1(no flags are affected)

The compare and subtract instructions in the 8085 both subtract one operand from another, and set flags accordingly. The subtract instruction stores the result in the accumulator, while the compare instruction does not - except for the flags, the compare instruction "throws" the result away.

A pseudo-op is an assembly language instruction that specifies an operation of the assembler i.e about the base register & its contents e.g. USING instruction. On the other hand, a machine-op instruction. That represents a machine instruction to the assembler e.g. BR instruction is a machine-op instruction

An accumulator is a register that is a part of a processor. It has more/faster instructions than other registers. Examples:/360: no accumulator8080: A6800: A and B8086: AX80386: EAXx86-64: RAXThe accumulator in an automatic transmission softens the shift between gears.

the different between direct and indirect adress instruction

The Instruction Location Counter is a variable inside of the assembler. While the Program Counter is a register. The PC solely keeps track of the next instruction in a program, ILC increments by each instruction's operand length.

A pseudo-instruction doesn't actually exist in the instruction set of a processor. A pseudo-instruction will be a convenient single name for one or more actual instructions. A common example is the unconditional jump instruction. Normally the syntax for this instruction would be: jmp address ...but the assembler might actually translate that into: cmp t0 r0 r0 jmp t0 address Which is basically checking to see if the zero register is equal to the zero register, and if so jump. Since this will always be true, it will always jump.

difference between micro operation and microinstruction

Major difference between Bus and Register is that B for Bus while R for Register

Genre is thus higher in the semiotic hierarchy than register.

A pseudo-instruction : A symbolic representation in a compiler or interpreter. An instruction : a simple statement in any language that defines a task or computation etc.

Ans: In the register addressing mode the operands are in registers which reside within the CPU. Register-mode instructions are 1-byte instructions and can be executed within the CPU without the need to reference memory for operands. But in the Register-indirect addressing mode the instruction specifies a register or a pair of registers in the processor whose contains give the address of the operand in memory. This mode uses 1-byte instructions even though the operand is in memory. Before using a register-indirect mode instruction, the programmer must ensure that the address of the operand is placed in the processor register with a previous transfer-type instruction. A reference to the register is then equivalent to specifying a memory address.

Copyright ยฉ 2020 Multiply Media, LLC. All Rights Reserved. The material on this site can not be reproduced, distributed, transmitted, cached or otherwise used, except with prior written permission of Multiply.