[1] There are two variants: FMA3 and FMA4 instructions have almost identical functionality, but are not compatible.
See XOP instruction set for more discussion of compatibility issues between Intel and AMD.
Supported commands include Explicit order of operands is included in the mnemonic using numbers "132", "213", and "231": as well as operand format (packed or scalar) and size (single or double).
This results in The incompatibility between Intel's FMA3 and AMD's FMA4 is due to both companies changing plans without coordinating coding details with each other.
The history can be summarized as follows: Different compilers provide different levels of support for FMA: