What is LR ARM assembly?
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. In the case of an exception, the return address is pushed onto the stack by hardware and the LR is set to EXC_RETURN (0xFFFFFFF1, 0xFFFFFFF9, or 0xFFFFFFFD).
What is area in ARM assembly?
The AREA directive instructs the assembler to assemble a new code or data section. Sections are independent, named, indivisible chunks of code or data that are manipulated by the linker.
What does ARM stand for?
Advanced RISC Machine
Acorn Computers first developed the Arm processor in the 1980s. Until recently, the name Arm was treated as an acronym, ARM, which at first stood for Acorn RISC Machine and then for Advanced RISC Machine. The acronym is still widely used, although Arm Limited uses only Arm when describing its processor technology.
What is R15 in ARM?
R15: PC (Program Counter). The Program Counter is automatically incremented by the size of the instruction executed. This size is always 4 bytes in ARM state and 2 bytes in THUMB mode. When a branch instruction is being executed, the PC holds the destination address.
What is DCD and DCW in ARM?
DCW (Define Constant Word) allocates one or more halfwords of memory, aligned on two-byte boundaries. 3. DCD (Define Constant Data) allocates one or more words of memory, aligned on four-byte boundaries.
What is ARM C?
The ARM C libraries. The ARM C libraries provide standard C functions, and helper functions used by the C and C++ libraries. The C libraries also provide target-dependent functions that are used to implement the standard C library functions such as printf in a semihosted environment.
What is R0 ARM?
Register usage in subroutine calls By convention, you use registers R0 to R3 to pass arguments to subroutines, and R0 to pass a result back to the callers. A subroutine that requires more than four inputs uses the stack for the additional inputs. To call subroutines, use a branch and link instruction.
What is DCD Assembly?
DCD (Define Constant Data) allocates one or more words of memory, aligned on four-byte boundaries.
What is DCD in ARM processor?
DCD and DCDU 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 . DCDU is the same, except that the memory alignment is arbitrary.
What assembly language does the Microsoft ARM Assembler use?
For the most part, the Microsoft ARM assembler uses the ARM assembly language, which is documented in the ARM Compiler armasm Reference Guide. However, the Microsoft implementations of some assembly directives differ from the ARM assembly directives. This article explains the differences. Microsoft Implementations of ARM Assembly Directives
What language is used for ARM assembly directives?
ARM Assembler Directives. For the most part, the Microsoft ARM assembler uses the ARM assembly language, which is documented in the ARM Compiler armasm Reference Guide. However, the Microsoft implementations of some assembly directives differ from the ARM assembly directives. This article explains the differences.
What is the difference between thumb and arm in assembler?
In the Microsoft ARM assembler, THUMB indicates that a CODE section contains Thumb code, and is the default for CODE sections. ARM indicates that the section contains ARM code.
What is assembler?
This set of mnemonics is the Assembly language of the computer and we use a program called Assembler to convert code from mnemonic representation to the computer-readable machine code, in the same way a compiler does for high-level languages. 1. Whirlwind Tour of ARM Assembly.