Encoding:

Format:

DOTP_U.df 

DOTP_U.H wd,ws,wt

DOTP_U.W wd,ws,wt

DOTP_U.D wd,ws,wt

Purpose:

Vector Unsigned Dot Product

Vector unsigned dot product (multiply and then pairwise add the adjacent multiplication results) to double width elements.

Description:

(wd[2i+1], wd[2i]) = unsigned(ws[2i+1]) * unsigned(wt[2i+1]) + 
unsigned(ws[2i]) * unsigned(wt[2i])

The unsigned integer elements in v ector wt are multiplied by unsigned integer elements in vector ws producing a result twice the size of the input operands. The multiplication results of adj acent odd/even elements are added and stored to the destination.

The operands are values in integer data format half the size of df. The results are values in integer data format df.

Restrictions:

No data-dependent exceptions are possible.

Operation:

DOTP_U.H
   for i in 0 .. WRLEN/16-1
      WR[wd]16i+15..16i = dotp_u(WR[ws]16i+15..16i, WR[wt]16i+15..16i, 8)
   endfor
DOTP_U.W
   for i in 0 .. WRLEN/32-1
      WR[wd]32i+31..32i = dotp_u(WR[ws]32i+31..32i, WR[wt]32i+31..32i, 16)
   endfor
DOTP_U.D
   for i in 0 .. WRLEN/64-1
      WR[wd]64i+63..64i = dotp_u(WR[ws]64i+63..64i, WR[wt]64i+63..64i, 32)
   endfor
function mulx_u(ts, tt, n)
   s = 0n || tsn-1..0 
   t = 0n || ttn-1..0
   p = s * t 
   return p2n-1..0
endfunction mulx_s
function dotp_u(ts, tt, n)
   p1 = mulx_u(ts2n-1..n, tt2n-1..n, n)
   p0 = mulx_u(tsn-1..0, ttn-1..0, n)
   p = p1 + p0
   return p2n-1..0
endfunction dotp_u

Exceptions:

Reserved Instruction Exception, MSA Disabled Exception.