What is the instruction set used by ARM?
What is the instruction set used by ARM?
The Arm architecture supports three instruction sets: A64, A32 and T32. The A64 and A32 instruction sets have fixed instruction lengths of 32-bits. The T32 instruction set was introduced as a supplementary set of 16-bit instructions that supported improved code density for user code.
What are the ARM instructions format?
They are move, arithmetic, logical, comparison and multiply instructions and multiply instructions.
What is ADC instruction?
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 does the S suffix of the ADD instruction do?
S. is an optional suffix. If S is specified, the condition code flags are updated on the result of the operation (see Conditional execution).
How many instructions are there in ARM and thumb together?
Thumb instructions operate with the standard ARM register configuration, allowing excellent interoperability between ARM and Thumb states. On execution, 16-bit Thumb instructions are transparently decompressed to full 32-bit ARM instructions in real time, without performance loss.
What are the salient features of ARM instruction set?
ARM has a number of RISC features, such as a large register set, fixed-length instructions, and a purely load-store architecture. In comparison, 32-bit x86 has six registers that are nominally general-purpose, although a lot of instructions require the use of specific registers.
What is instruction set used by ARM7?
What is the instruction set used by ARM7? Explanation: ARM introduced the Thumb 16-bit instruction set providing improved code density compared to previous designs. The most widely used ARM7 designs implement the ARMv4T architecture, but some implement ARM3 or ARMv5TEJ.
What is RSB instruction in arm?
The RSB instruction subtracts the value in Rn from the value of Operand2 . This is useful because of the wide range of options for Operand2 .
What is Das instruction?
DAS–Decimal Adjust AL after Subtraction Adjusts the result of the subtraction of two packed BCD values to create a packed BCD result. The AL register is the implied source and destination operand. The DAS instruction then adjusts the contents of the AL register to contain the correct 2-digit, packed BCD result.
What does ADDS mean in ARM?
11. The extra s character added to the ARM instruction mean that the APSR (Application Processor Status Register) will be updated depending on the outcome of the instruction.
What is the syntax of add instruction?
Binary Operations
| Instruction Mnemonic | Example | Description |
|---|---|---|
| SUB | SUB EAX, 0002h | Subtract the 2 from the register |
| SBB | SBB EBX, 0002h | Subtract with borrow |
| MUL | MUL EBX | Unsigned multiply EAX by EBX; results in EDX:EAX |
| DIV | DIV EBX | Unsigned divide |
What is the difference between ARM instruction and Thumb instruction?
ARM instructions are 32 bits wide. Thumb instructions are 16 or 32-bits wide. The ARM instruction set is a set of 32-bit instructions providing a comprehensive range of operations. The Thumb instruction set provides better code density, at the expense of performance.
What does the arm ldrle instruction Do?
ARM uses a load-store model for memory access which means that only load/store (LDR and STR) instructions can access memory. While on x86 most instructions are allowed to directly operate on data in memory, on ARM data must be moved from memory into registers before being operated on.
What does BX LR do in arm assembly language?
LR is used to store the return program counter (PC) when a subroutine or function is called-for example, when you’re using the branch and link (BL) instruction: The most basic branch instructions are as follows: In BX instructions, the LSB of the value contained in the register determines the next state (Thumb/ARM) of the processor.
What is ARM instruction set?
ARM, previously Advanced RISC Machine, originally Acorn RISC Machine, is a family of reduced instruction set computing (RISC) architectures for computer processors, configured for various environments.
What is the ARM Thumb instruction set?
– A few THUMB instructions can access r8 – r15. – THUMB instruction set also follows Load Store architecture like ARM instruction set. – It can support 8 bit, 16 bits and 32 bit data types. – THUMB instructions are less regular. – Original THUMB instruction set mapped its instructions onto ARM Instructions before decoding it (refer to Figure b).
