supervisor mode in arm processor

commands, variable instruction lengths, and multiple addressing methods. These are also the disadvantages of CISC, because they greatly increase the difficulty of decoding, however, with the current high-speed hardware development, the speed improvement caused by complex commands is far less than a waste of time on decoding. In addition to the x86 instruction sets used in the personal PC market, CISC is no longer needed for servers and larger systems. The reason why x86 still exists is to be co

This article Reprinted from: http://blog.csdn.net/lizhiguo0532/article/details/5922639 Thanks very much to the original author! The ARM processor has a total of 7 running modes:User Mode (usr)-normal Program Execution Mode | -- Fast interrupt mode (FIQ) -- used for high-spee

ARM processor memory allocation details The Samsung 2440 processor provides 1 GB access to external storage space, divided into 8The size of each bank is 128 MB. The memory access bus width from bank1 to bank7 is programmable, which can be 8bit, 16bit, 32bit, and bank0 can only be 16bit/32bit. Bank0 to bank5 only have Rom and SRAM interfaces, which can be used fo

register and can be read and written.R13 is a stack pointer register that holds the stack pointerR14 is the program connection register, when the BL subroutine call instruction is executed, R14 gets a R15 backup, and when an interrupt or an exception occurs, R14 saves the return value of R15R15 is a program counter(A/C) PSR: (Flag bit register)T-bit: 1--CPU in thumb State, 0--cpu in arm state;I, F (interrupt prohibit bit): The first stop interruption

Writing application instances does not belong to the Linux operating system transplantation. However, to ensure the integrity of this series of articles, we provide a series of instances for developing applications for Embedded Linux. The following tools are required to write Linux applications: (1) compiler: gcc GCC is the most important development tool in Linux. It is the gnu c and C ++ compilers. Its basic usage is GCC [Options] [filenames]. We should use

I. Arm has two working states: (1) arm status. At this time, the processor executes the 32-bit arm command. (2) thumb status. At this time, the processor executes a 16-bit half-aligned thumb command. 2. Arm processors must b

1, user mode: USR, the normal application mode of operation;2, Fiq mode: Fiq, fast interrupt mode, when a program is running, suddenly create an interrupt, and this interruption is a rapid interruption, then into the fast interrupt mode to run;3, IRQ

use the small-end mode, including some PCI bus, flash and other devices used in network equipment, this also requires hardware engineers to pay attention to Terminal Mode Conversion in hardware design. Ii. Use a processor of large and small terminalsThe commonly used x86 structure is the small-end mode, while the c51

ARM's 8 modes of operation USER SYSTEM SUPERVISOR chip reset and software execution SWI FIQ Irq When SECURE MONITOR private data is executed, the user software calls the SMI to enter ABORT access to memory data and instruction prefetch failure UNDEFINED when executing an unrecognized instruction system mode and user mode public registers, but has the ability to

states: 1. Arm status: the processor executes 32-bit arm commands with the same words; 2. Thumb status: the processor executes a 16-bit half-aligned thumb command; During the process of running the program, you can switch between the two States. The change of the processor's working status does not affect the working