"Assembly instruction" the PSR delivery instruction of ARM instruction set

The arm instruction set provides two instructions to directly control the status register (psr,program State Register). The Mrs Instruction is used to transmit the value of the CPSR or SPSR to a register; In contrast, the MSR transmits the contents of a register to CPSR or SPSR. These two instructions are combined to read/write to CPSR and SPSR.

Cpsr_c represents the low 8 bits in this 32-bit, which is the control bit

CPSR has 4 8-bit zones: Flag field (F), state field (S), extended domain (X), control domain (C)

The following is a general example of how the PSR command is observed:

1 "Switch to IRQ mode"

2 "Open IRQ Interrupt"

3 "Switch to user mode to perform the app"

"Assembly instruction" the PSR delivery instruction of ARM instruction set