NASM 2.05 based x86 Instruction Reference[ch154]
A.5.133 LDMXCSR: Load Streaming SIMD Extension Control/Status LDMXCSR mem32 ; 0F AE /2 [KATMAI,SSE] LDMXCSR loads 32-bits of data from the specified memory location into the MXCSR control/status register. MXCSR is used to enable masked/unmasked exception handling, to set rounding modes, to set flush- to-zero mode, and to view exception status flags. For details of the MXCSR register, see the Intel processor docs. See also STMXCSR (section A.5.302