PPACKLO

Operation

Packs source predicate positions into the lower half of narrower destination positions.

Assembler Syntax

PPACKLO.{W|L|Q}(z) Pn(p), Pn(q)

Privilege

Unprivileged

Required CPUID flags

VECTOR

PPACKLO reads the significant predicate positions for the selected W, L, or Q source element width. It copies those positions in lane order to the lower half of the significant destination positions for elements half that width. The complete destination predicate image is written: the upper half of its significant positions and every bit outside its significant positions are cleared. The operation leaves FLAGS unchanged.

In the illustrated 16-byte instance, the significant word-predicate positions of source Pn are copied in lane order to the lower half of the byte-predicate positions of new Pq. Every other bit is cleared, and the same lower-half rule scales with VLEN.

PPACKLO.W lower-half predicate packing

2.75in

Encodings

PPACKLO.{W|L|Q}(z) Pn(p), Pn(q)

Format: Instruction format for PPACKLO.{W|L|Q}(z) Pn(p), Pn(q)

Format: Instruction format for PPACKLO.{W|L|Q}(z) Pn(p), Pn(q)

size — allowed: 0x1..0x3 [reserved_vector_element_type]