Encoding:

Format:

VSHF.df 

VSHF.B wd,ws,wt

VSHF.H wd,ws,wt

VSHF.W wd,ws,wt

VSHF.D wd,ws,wt

Purpose:

Vector Data Preserving Shuffle

Vector elements selective copy based on the control vector preserving the input data vectors.

Description:

wd = vector_shuffle(control(wd), ws, wt)

concatenation of vectors ws and wt into

The vector shuffle instructions selectively copy data elements from the vector wd based on the corresponding control element in wd.

The least significant 6 bits in wd control elements modulo the number of elements in the concatenated vectors ws, wt specify the index of the source element. If bit 6 or bit 7 is 1, there will be no copy, but rather the destination element is set to 0.

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

Restrictions:

No data-dependent exceptions are possible.

Operation:

VSHF.B
   v = WR[ws] || WR[wt]
   for i in 0 .. WRLEN/8-1
      k = WR[wd]8i+5..8i mod (WRLEN/4)
      if WR[wd]8i+7..8i+6 != 0 then
         WR[wd]8i+7..8i = 0
      else
         WR[wd]8i+7..8i = v8k+7..8k
      endif
   endfor
VSHF.H
   v = WR[ws] || WR[wt]
   for i in 0 .. WRLEN/16-1
      k = WR[wd]16i+5..16i mod (WRLEN/8)
      if WR[wd]16i+7..16i+6 !=0 then
         WR[wd]16i+15..16i = 0
      else
         WR[wd]16i+15..16i = v16k+15..16k
      endif
   endfor
VSHF.W
   v = WR[ws] || WR[wt]
   for i in 0 .. WRLEN/32-1
      k = WR[wd]32i+5..32i mod (WRLEN/16)
      if WR[wd]32i+7..32i+6 != 0 then
         WR[wd]32i+31..32i = 0
      else
         WR[wd]32i+31..32i = v32k+31..32k
      endif
   endfor
VSHF.D
   v = WR[ws] || WR[wt]
   for i in 0 .. WRLEN/64-1
      k = WR[wd]64i+5..64i mod (WRLEN/32)
      if WR[wd]64i+7..64i+6 != 0 then
         WR[wd]64i+63..64i = 0
      else
         WR[wd]64i+63..64i = v64k+63..64k
      endif
   endfor

Exceptions:

Reserved Instruction Exception, MSA Disabled Exception.