xxsetaccz

VSX Set Accumulator to Zero

xxsetaccz AT

Clears a 512-bit Accumulator register (composed of 4 VSRs) to zero.

Details

Clears the 512-bit accumulator register AT (which consists of four 128-bit VSRs) to all zeros. This instruction is part of the MMA (Matrix Multiply Assist) extension and provides a fast way to initialize an accumulator before a sequence of matrix operations. No condition registers or status fields are affected.

Pseudocode Operation

ACC[AT] ← 0x0000...0000 (512 bits of zeros)

Programming Note

This instruction zeroes out all elements of the specified VSX accumulator. Ensure that VSX is enabled in the MSR register before using this instruction; otherwise, a VSX_Unavailable exception will be raised. This operation is useful for initializing accumulators or resetting them between operations.

Example

xxsetaccz acc0

Encoding

Binary Layout
31
0
/
6
/
11
AT
16
185
21
/
31
 
Format X-form
Opcode 0x7C030162
Extension MMA
Registers Altered MSR

Operands

  • AT
    Accumulator (0-7)