What is Stmfd?

What is Stmfd?

Store Multiple Decrement Before (Store Multiple Full Descending) stores multiple registers to consecutive memory locations using an address from a base register.

What is LR in ARM?

On an ARM Cortex M series device, the link register (LR or R14) is a core register that stores the return address, such as when making a function call.

What is MOV in arm?

The MOV instruction copies the value of Operand2 into Rd . In certain circumstances, the assembler can substitute MVN for MOV , or MOV for MVN . Be aware of this when reading disassembly listings.

What is Ldrsh?

Load Register Signed Halfword (register) calculates an address from a base register value and an offset register value, loads a halfword from memory, sign-extends it to form a 32-bit word, and writes it to a register. The offset register value can be shifted left by 0, 1, 2, or 3 bits.

What is ADR Assembly?

The ADR instruction loads an address within a certain range, without performing a data load. ADR accepts a PC-relative expression, that is, a label with an optional offset where the address of the label is relative to the PC.

What is PC and LR?

LR is the link register a shortcut for r14. And PC is the program counter a shortcut for typing r15. When you perform a call, called a branch link instruction, bl, the return address is placed in r14, the link register. the program counter pc is changed to the address you are branching to.

What is the R14 register?

Register R14 is used as the subroutine Link Register (LR). Register R14 receives the return address when a Branch with Link ( BL or BLX ) instruction is executed. You can treat R14 as a general-purpose register at all other times.

What is the purpose of the stack?

Generally speaking, the Stack is a memory region within the program/process. This part of the memory gets allocated when a process is created. We use Stack for storing temporary data such as local variables of some function, environment variables which helps us to transition between the functions, etc.

What is the difference between MOV and LDR?

Re: ARM Assembly: ldr versus mov So mov is faster, but can only be used for 0-255. (Small numbers.) Ldr can move anything, but is slower.

What is DCD in ARM?

ARM Compiler toolchain Assembler Reference Version 5.02 The DCD directive allocates one or more words of memory, aligned on four-byte boundaries, and defines the initial runtime contents of the memory. & is a synonym for DCD .

Whats the difference between ADR and LDR?

LDR obtains the immediate data by putting the data in the program code and uses a PC relative load to get the data into the register. ADR tries to generate the immediate value by adding or subtracting instructions (for example, based on the current PC value).

What is LDR assembly?

The LDR Rd,= label pseudo-instruction places an address in a literal pool and then loads the address into a register.

What does BX LR mean?

branch to link register
Written by “bl” (branch and link, like function call), often saved with a push/pop sequence, read by “bx lr” (branch to link register) or the pop.

What does the R stand for in Rax?

rax is the 64-bit, “long” size register. It was added in 2003 during the transition to 64-bit processors. eax is the 32-bit, “int” size register.

What is R13 register used for?

R13 is defined in the Thumb instruction set so that its use is primarily as a stack pointer. R13 is normally identified as Stack Pointer (SP) in Thumb instructions. In 32-bit Thumb instructions, if you use SP as a general purpose register beyond the architecturally defined constraints, the results are unpredictable.

What is the advantage of stack?

Comparison Table for Advantages & Disadvantages of Stack

What is TST command?

The TST instruction performs a bitwise AND operation on the value in Rn and the value of Operand2 . This is the same as a ANDS instruction, except that the result is discarded. The TEQ instruction performs a bitwise Exclusive OR operation on the value in Rn and the value of Operand2 .