wiki:IDISA_Movement

Version 14 (modified by cameron, 8 years ago) (diff)

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IDISA Field Movement Operations

The tables below list the various IDISA field movement operations on vectors of w-bit fields, together with their description and semantic specification.

An important characteristic of these operations is that fields may be moved or rearranged in various ways, but the contents of the fields remain unchanged.

Constant Fill Operations

The operations r = mvmd<w>::fill<c>() and r = mvmd<w>::fill(c) fill each w-bit field with an integer value c. In the first case, the fill value is a compile-time constant.

Unary Movement Operations

These operations generally have the form r = mvmd<w>::op(a) for each operation op, where a is an operand vectors of w-bit fields and r is the corresponding result vector. Let N = W/w be the number of w-bit fields in a vector.

splat<j> splat ri = aj
slli<j> shift left logical immediate ri = ai+j if i + j <= N, 0 otherwise
srli<j> shift right logical immediate ri = ai-j if i > j, 0 otherwise
shufflei<m> shuffle immediate ri = at, where t = index(m, i)

The immediate constant value used for shufflei is computed by one of the functions:

shufflemask2(s1, s2) compute mask for selecting 1 of 2 fields
shufflemask4(s1, s2, s3, s4) compute mask for selecting 1 of 4 fields
shufflemask8(s1, s2, s3, s4, s5, s6, s7, s8) compute mask for selecting 1 of 8 fields
shufflemask16(s1, s2, s3, s4, s5, s6, s7, s8, s9, s10, s11, s12, s13, s14, s15, s16) compute mask for selecting 1 of 16 fields

Binary Movement Operations

These operations generally have the form r = mvmd<w>::op(a, b) for each operation op, where a and b are operand vectors of w-bit fields and r is the corresponding result vector.

dslli<j> double shift left logical immediate ri = ai+j if i + j <= N, bi + j - N otherwise
dsrli<j> double shift right logical immediate ri = ai + N -j if i <= j, bi - j otherwise
shuffle shuffle ri = at, where t = bi