VEX_R
if (reg != NULL && ((VEX_R & vex_byte1) == 0))
if ((VEX_R & evex_byte1) == 0) {
if ((evex_byte1 & VEX_R) == 0)
vex_R = ((opcode3 & VEX_R) & 0x0F) >> 3;
vex_byte1 = (opcode3 & VEX_R) | VEX_X | VEX_B;
vex_R = (opcode3 & VEX_R) >> 3;
vex_byte1 = opcode3 & (VEX_R | VEX_X | VEX_B);