Understanding ARM NEON instruction

hi i am trying to understand ARM NEON instruction and encountered with vqrdmulh instruction. i am particularly interested in saturation case in instruction i am not getting any case with saturation ....
NEON: Cortex A7 is 4 times slower than Cortex A8 ?

I'm seeing Cortex-A7 cycle-timing table here : http://hardwarebug.org/2014/05/15/cortex-a7-instruction-cycle-timings/ For example, VADD.F32 Dd, Dn, Dm takes 2 cycles VADD.F32 Qd, Qn, Qm takes 4 cycles...
Bit 22 in some LD/ST instructions (Cortex-A7)

I wonder if the bit 22 has some function in instructions like LDRH, STRH, LDRSBT, LDRD, ... (bits 27, 26, 25 = 0, 0, 0)? 22 c c c c 0 0 0 0 U 1 1 0 n n n n t t t t x x x...
ARM MUL instruction

Still more instruction things giving me head ache. This time it's the MUL-instruction. What the heck means: Multiply multiplies two register values. The least significant 32 bits of the result are written...
Register 'names' in instruction descriptions

The registers in the instructions are usually 'named' Rn, Rm, Rd, ... Is there some deeper meaning in the names? Usually Rd seems to mean 'destination register' Sometimes Rn is the only operand, sometimes...