Encoding:

Format:

NLZC.df 

NLZC.B wd,ws

NLZC.H wd,ws

NLZC.W wd,ws

NLZC.D wd,ws

Purpose:

Vector Leading Zeros Count

Vector element count of leading bits set to 0.

Description:

wd[i] = leading_zero_count(ws[i])

The number of leading zeroes for elements in vector ws is stored to the elements in vector wd.

The operands and results are values in integer data format df.

Restrictions:

No data-dependent exceptions are possible.

Operation:

NLZC.B
   for i in 0 .. WRLEN/8-1
      WR[wd]8i+7..8i = leading_zero_count(WR[ws]8i+7..8i, 8)
   endfor
NLZC.H
   for i in 0 .. WRLEN/16-1
      WR[wd]16i+15..16i = leading_zero_count(WR[ws]16i+15..16i, 16)
   endfor
NLZC.W
   for i in 0 .. WRLEN/32-1
      WR[wd]32i+31..32i = leading_zero_count(WR[ws]32i+31..32i, 32)
   endfor
NLZC.D
   for i in 0 .. WRLEN/64-1
      WR[wd]64i+63..64i = leading_zero_count(WR[ws]64i+63..64i, 64)
   endfor
function leading_zero_count(tt, n)
   z = 0
   for i in n-1..0
      if tti = 1 then
          return z
      else
          z = z + 1
      endif
endfunction leading_zero_count

Exceptions:

Reserved Instruction Exception, MSA Disabled Exception.