Field Name             Bits   Default Description
INDEX                  8:0    0x0     Instruction (TYPE == GA_US_VECTOR_INST) or
                                      constant (TYPE == GA_US_VECTOR_CONST)
                                      number at which to start loading. The GA will then
                                      expect n*6 (instructions) or n*4 (constants) writes to
                                      GA_US_VECTOR_DATA. The GA will self-increment
                                      until this register is written again. For instructions, the
                                      GA expects the dwords in the following order:
                                      US_CMN_INST, US_ALU_RGB_ADDR,
                                      US_ALU_ALPHA_ADDR, US_ALU_ALPHA,
                                      US_RGB_INST, US_ALPHA_INST, US_RGBA_INST.
                                      For constants, the GA expects the dwords in RGBA
                                      order.
TYPE                   16     0x0     Specifies if the GA should load instructions or constants.
                                      POSSIBLE VALUES:
                                      00 - Load instructions - INDEX is an instruction index
                                      01 - Load constants - INDEX is a constant index
CLAMP                  17     0x0     POSSIBLE VALUES:
                                      00 - No clamping of data - Default
                                      01 - Clamp to [-1.0,1.0] constant data
