Instruction set

The aarch32 instruction set is divided into several categories, each of which serves a specific purpose. The main categories of instructions in aarch32 include:

Category	Description
Data processing	Perform arithmetic and logical operations on data
Load/store	Move data between memory and registers
Control flow	Control the flow of execution in a program
Exception-generating	Trigger exceptions or interrupts
Synchronization	Manage concurrent access to shared data
System	Access system resources or perform other privileged operations

This is just a brief overview of some of the main instruction categories in the aarch32 ISA. There are many other instruction categories and specific instructions within each category, each of which serves a specific purpose and can be used in various ways to implement a given algorithm or program.

Data porcessing

Instruction	Description
ADD	Add two registers or a register and an immediate value
SUB	Subtract two registers or a register and an immediate value
MUL	Multiply two registers
DIV	Divide two registers
AND	Perform a bitwise AND operation on two registers or a register and an immediate value
OR	Perform a bitwise OR operation on two registers or a register and an immediate value
XOR	Perform a bitwise XOR operation on two registers or a register and an immediate value
NOT	Perform a bitwise NOT operation on a register
SHL	Shift the bits in a register to the left by a specified number of positions
SHR	Shift the bits in a register to the right by a specified number of positions

Note that this is not an exhaustive list of data processing instructions in the aarch32 instruction set. There are many other instructions that can be used to perform a wide range of operations on data. The specific instructions available and their exact behavior may vary depending on the implementation of the aarch32 instruction set.

Load/Store

Instruction	Description
LDR	Load a word from memory into a register
STR	Store a word from a register into memory
LDRSB	Load a signed byte from memory into a register
LDRSH	Load a signed half-word from memory into a register
LDRB	Load an unsigned byte from memory into a register
LDRH	Load an unsigned half-word from memory into a register
STB	Store a byte from a register into memory
STH	Store a half-word from a register into memory

Note that this is not an exhaustive list of load/store instructions in the aarch32 instruction set. There are many other instructions that can be used to load and store data from memory using a variety of addressing modes and data types. The specific instructions available and their exact behavior may vary depending on the implementation of the aarch32 instruction set.

Control flow

Instruction	Description
B	Unconditionally branch to a specified address
BEQ	Branch to a specified address if two registers are equal
BNE	Branch to a specified address if two registers are not equal
BL	Branch to a specified address and save the return address in a register
BLE	Branch to a specified address if the value in a register is less than or equal to zero
BLX	Branch to a specified address and switch to Thumb mode
BX	Branch to a specified address and switch to ARM mode

Note that this is not an exhaustive list of control flow instructions in the aarch32 instruction set. There are many other instructions that can be used to control the flow of execution in a program, such as conditional branches and subroutine calls. The specific instructions available and their exact behavior may vary depending on the implementation of the aarch32 instruction set.

Exception-generating

Instruction	Description
SVC	Trigger a supervisor call (SVC) exception
BKPT	Trigger a breakpoint exception
HVC	Trigger a hypervisor call (HVC) exception

Note that this is not an exhaustive list of exception-generating instructions in the aarch32 instruction set. There are many other instructions that can be used to trigger different types of exceptions or interrupts, such as data abort and undefined instruction exceptions. The specific instructions available and their exact behavior may vary depending on the implementation of the aarch32 instruction set.

Synchronization

Instruction	Description
DMB	Ensure that all memory accesses before this instruction have completed before any memory accesses after this instruction are performed
DSB	Ensure that all memory accesses before this instruction have completed before the processor can execute any subsequent instructions
ISB	Ensure that all instructions before this instruction have completed before any subsequent instructions are executed

Note that this is not an exhaustive list of synchronization instructions in the aarch32 instruction set. There are many other instructions that can be used to manage concurrent access to shared data by multiple threads or processes. The specific instructions available and their exact behavior may vary depending on the implementation of the aarch32 instruction set.

System

Instruction	Description
MRS	Read the value of a system register into a register
MSR	Write a value to a system register from a register
CPS	Change the current processor mode or the state of interrupts
SYS	Perform a privileged operation or access a system resource

Note that this is not an exhaustive list of system instructions in the aarch32 instruction set. There are many other instructions that can be used to access system resources or perform other privileged operations. The specific instructions available and their exact behavior may vary depending on the implementation of the aarch32 instruction set.