cpsr与cpsr_c的区别-嵌入式

2dmin

CPSR有4个8位区域：标志域（F）、状态域（S）、扩展域（X）、控制域（C）MSR - Load specified fields of the CPSR or SPSR with an immediate constant, or from the contents of a general-purpose register.Syntax:MSR{cond} <psr>_<fields>, #immed_8r MSR{cond} <psr>_<fields>, Rm where: cond is an optional condition code. <psr> is either CPSR or SPSR. <fields> specifies the field or fields to be moved. <fields> can be one or more of:c control field mask byte (PSR[7:0]) x extension field mask byte (PSR[15:8]) s status field mask byte (PSR[23:16) f flags field mask byte (PSR[31:24]). immed_8r is an expression evaluating to a numeric constant. The constant must correspond to an 8-bit pattern rotated by an even number of bits within a 32-bit word. Rm is the source register.C 控制域屏蔽字节(psr[7:0])X 扩展域屏蔽字节(psr[15:8])S 状态域屏蔽字节(psr[23:16])F 标志域屏蔽字节(psr[31:24])常用于MRS或MSR指令,用于psr中的值转移到寄存器或把寄存器的内容加载到psr中.如:MSR CPSR_c，＃0xd3