xxmtacc

VSX Move to Accumulator

xxmtacc AT

Copies data from 4 adjacent VSRs into an Accumulator.

Encoding

Binary Layout

31

0:5

/

6:10

/

11:15

AT

16:20

153

21:30

/

31

 

Format X-form

Opcode 0x7C010162

Extension MMA

Operands

• AT
  Target ACC

Example

xxmtacc acc0

Registers Altered

MSR

Related

More in MMA

Reference

View in PowerISA v3.1C Specification ↗ OPF Power ISA v3.1C

Description

Copies data from four consecutive VSRs (VSR[4×AT], VSR[4×AT+1], VSR[4×AT+2], VSR[4×AT+3]) into the 512-bit accumulator AT. This instruction transfers vector data from the VSR file into MMA accumulator state. This instruction requires MMA support and does not affect any condition registers or status fields.

Operation

ACC[AT][0:127] ← VSR[4×AT]
ACC[AT][128:255] ← VSR[4×AT+1]
ACC[AT][256:383] ← VSR[4×AT+2]
ACC[AT][384:511] ← VSR[4×AT+3]

Programming Note

Ensure VSX is enabled in the MSR before using xxmtacc; otherwise, a VSX_Unavailable exception will occur. This instruction moves data from four consecutive vector scalar registers into the accumulator, so verify register allocation to avoid unintended data movement.