image/svg+xml LDMXCSR—Load MXCSR Register Instruction Operand Encoding Description 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 Intel® 64 and IA-32 Architectures Software Devel- oper’s Manual, Volume 1 , for a description of the MXCSR register and its contents. The LDMXCSR instruction is typically used in conjunction with the (V)STMXCSR instruction, which stores the contents of the MXCSR register in memory. The default MXCSR value at reset is 1F80H. If a (V)LDMXCSR instruction clears a SIMD floating-point exception mask bit and sets the corresponding exception flag bit, a SIMD floating-point exception will not be immediately generated. The exception will be generated only upon the execution of the next instruction that meets both conditions below: • the instruction must operate on an XMM or YMM register operand, • the instruction causes that particular SIMD floating-point exception to be reported. This instruction’s operation is the same in non-64-bit modes and 64-bit mode. If VLDMXCSR is encoded with VEX.L= 1, an attempt to execute the instruction encoded with VEX.L= 1 will cause an #UD exception. Note: In VEX-encoded versions, VEX.vvvv is reserved and must be 1111b, otherwise instructions will #UD. Operation MXCSR := m32; C/C ++ Compiler Intrinsic Equivalent _mm_setcsr(unsigned int i) Numeric Exceptions None Other Exceptions See Table2-22, “Type 5 Class Exception Conditions”; additionally: #GPFor an attempt to set reserved bits in MXCSR. #UDIf VEX.vvvv ≠ 1111B. Opcode/ Instruction Op/ En 64/32-bit Mode CPUID Feature Flag Description NP 0F AE /2 LDMXCSR m32 MV/VSSELoad MXCSR register from m32 . VEX.LZ.0F.WIG AE /2 VLDMXCSR m32 MV/VAVXLoad MXCSR register from m32. Op/EnOperand 1Operand 2Operand 3Operand 4 MModRM:r/m (r)NANANA This UNOFFICIAL reference was generated from the official Intel® 64 and IA-32 Architectures Software Developer’s Manual by a dumb script. There is no guarantee that some parts aren't mangled or broken and is distributed WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE .