Encoding:

Format:

SAT_S.df 

SAT_S.B wd,ws,m

SAT_S.H wd,ws,m

SAT_S.W wd,ws,m

SAT_S.D wd,ws,m

Purpose:

Immediate Signed Saturate

Immediate selected bit width saturation of signed values.

Description:

wd[i] = saturate_signed(ws[i], m+1)

Signed elements in vector ws are saturated to signed values of m+1 bits without changing the data width. The result is written to vector wd.

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

Restrictions:

No data-dependent exceptions are possible.

Operation:

SAT_S.B
   for i in 0 .. WRLEN/8-1
      WR[wd]8i+7..8i = sat_s(WR[ws]8i+7..8i, 8, m+1)
   endfor
SAT_S.H
   for i in 0 .. WRLEN/16-1
      WR[wd]16i+15..16i = sat_s(WR[ws]16i+15..16i, 16, m+1)
   endfor
SAT_S.W
   for i in 0 .. WRLEN/32-1
      WR[wd]32i+31..32i = sat_s(WR[ws]32i+31..32i, 32, m+1)
   endfor
SAT_S.D
   for i in 0 .. WRLEN/64-1
      WR[wd]64i+63..64i = sat_s(WR[ws]64i+63..64i, 64, m+1)
   endfor
function sat_s(tt, n, b)
   if ttn-1 = 0 and ttn-1..b-1 != 0n-b+1 then
      return 0n-b+1 || 1b-1
   endif
   if ttn-1 = 1 and ttn-1..b-1 != 1n-b+1 then
      return 1n-b+1 || 0b-1
   else
      return tt
   endif
endfunction sat_s

Exceptions:

Reserved Instruction Exception, MSA Disabled Exception.