The orginal VMX supported SIMD integer byte, halfword, and word, and single float data types within a separate (from GPR and FPR) bank of 32 x 128-bit vector registers. These operations like to stay within their (SIMD) lanes except where the operation changes the element data size (integer multiply, pack, and unpack). This is complimented by bit logical and shift / rotate / permute / merge instuctions that operate on the vector as a whole.  Some operation (permute, pack, merge, shift double, select) will select 128 bits from a pair of vectors (256-bits) and deliver 128-bit vector result. These instructions will cross lanes or multiple registers to grab fields and assmeble them into the single register result. The PowerISA 2.07B Chapter 6. Vector Facility is organised starting with an overview (chapters 6.1- 6.6): 6.1 Vector Facility Overview . . . . . . . . . . . . . . . . . . . . 227 6.2 Chapter Conventions. . . . . . . . . . . . . . . . . . . . . . . 227 6.2.1 Description of Instruction Operation . . . . . . . . . . . . . 227 6.3 Vector Facility Registers . . . . . . . . . . . . . . . . . . . 234 6.3.1 Vector Registers . . . . . . . . . . . . . . . . . . . . . . . 234 6.3.2 Vector Status and Control Register . . . . . . . . . . . . . . 234 6.3.3 VR Save Register . . . . . . . . . . . . . . . . . . . . . . . 235 6.4 Vector Storage Access Operations . . . . . . . . . . . . . . . . 235 6.4.1 Accessing Unaligned Storage Operands . . . . . . . . . . . . . 237 6.5 Vector Integer Operations . . . . . . . . . . . . . . . . . . . 238 6.5.1 Integer Saturation . . . . . . . . . . . . . . . . . . . . . . 238 6.6 Vector Floating-Point Operations . . . . . . . . . . . . . . . . 240 6.6.1 Floating-Point Overview . . . . . . . . . . . . . . . . . . . 240 6.6.2 Floating-Point Exceptions . . . . . . . . . . . . . . . . . . 240 6.7 Vector Storage Access Instructions . . . . . . . . . . . . . . . 242 6.7.1 Storage Access Exceptions . . . . . . . . . . . . . . . . . . 242 6.7.2 Vector Load Instructions . . . . . . . . . . . . . . . . . . . 243 6.7.3 Vector Store Instructions. . . . . . . . . . . . . . . . . . . 246 6.7.4 Vector Alignment Support Instructions. . . . . . . . . . . . . 248 Then a chapter on storage (load/store) access for vector and vector elements: