Need A Vhdl Code

hi, i want a vhdl code for following logic.

i have 20 signed numbers,like.

-2 -2 0 0 0 0 -2 -2 0 0 0 0 2 2 0 0 0 0 2 2

1) i want to put them in group of 4 numbers like,

-2-200 00-2-2 0000 2200 0022

2)i want sum of that all each group internally like

-2+-2+0+0 = -4

0+0+-2+-2= -4

0+0+0+0=0

2+2+0+0=4

0+0+2+2=4

3) i want put this answers in seperate memory

like,

-4 -4 0 4 4

last i want this signed vector in memory.

can anyone help me?

thank u.

regards,

AAP