The GameCube/Wii vector ISA instruction was not Altivec, and not very similar. It used 64-bit vectors (packed as two 32 bit floats usually), so half the size of

The GameCube/Wii vector ISA instruction was not Altivec, and not very similar. It used 64-bit vectors (packed as two 32 bit floats usually), so half the size of Altivec, NEON, and most of its contemporaries. These packed vector instructions shared the register file with the floating point unit (that is, an FP register could contain either a 64-bit float acted on by a normal floating point instruction or two 32-bit floats acted on by a vector instruction), rather than having a dedicated separate register file like Altivec. And most of the fun instructions had no equivalent.