Loads the source operand into the MXCSR control/status register. The source operand is a 32- bit memory location. See "MXCSR Control and Status Register" in Chapter 10, of the IA-32 Intel Architecture Software Developer's Manual, Volume 1, for a description of the MXCSR register and its contents.
The LDMXCSR instruction is typically used in conjunction with the STMXCSR instruction, which stores the contents of the MXCSR register in memory.
The default MXCSR value at reset is 1F80H.
If a LDMXCSR instruction clears an SIMD floating-point exception mask bit and sets the corresponding exception flag bit, an SIMD floating-point exception will not be immediately generated.
The exception will be generated only upon the execution of the next SSE or SSE2 instruction that causes that particular SIMD floating-point exception to be reported.