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Q277FreeSystemVerilog

Compact live allocations

Difficulty
Hard
Topic
Memory Systems
Language
SV
Interview prompt

Question

Compact live allocations toward the allocator base, return an old-to-new relocation map, and rebuild one consolidated free interval.

Starting point

Question code

function void compact(
  ref int unsigned relocated_addr[int unsigned]
);
Reviewed example

Trace one case

Input
allocator=[0,99]; live blocks=(base=10,size=20),(base=50,size=10)
Expected output
relocations={10->0,50->20}; consolidated free range=[30,99]

Packing in allocation order keeps blocks nonoverlapping and advances the final free cursor to 30.

What to cover

Requirements

  1. Track live allocation bases and sizes.
  2. Preserve allocation order and prevent overlap during conceptual movement.
  3. Return a relocation entry for every moved allocation.
  4. Rebuild the free list from the final packed cursor to the allocator limit.
Continue practicing
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