Floating-point Intrinsics for Streaming SIMD Extensions

You should be familiar with the hardware features provided by the Streaming SIMD Extensions when writing programs with the intrinsics. The following are four important issues to keep in mind:

• Certain intrinsics, such as _mm_loadr_ps and _mm_cmpgt_ss, are not directly supported by the instruction set. While these intrinsics are convenient programming aids, be mindful that they may consist of more than one machine-language instruction.
• Floating-point data loaded or stored as __m128 objects must be generally 16-byte-aligned.
• Some intrinsics require that their argument be immediates, that is, constant integers (literals), due to the nature of the instruction.
• The result of arithmetic operations acting on two NaN (Not a Number) arguments is undefined. Therefore, FP operations using NaN arguments will not match the expected behavior of the corresponding assembly instructions.