user
54 lines
1.3 KiB
Plaintext
54 lines
1.3 KiB
Plaintext
@startuml
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scale 620 height
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top to bottom direction
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skinparam backgroundColor transparent
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skinparam shadowing false
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skinparam defaultFontName Monospace
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skinparam defaultFontSize 10
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skinparam classBorderColor #2c7794
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skinparam classBackgroundColor #edf6fa
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skinparam ArrowColor #8095a1
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title A2 STRUCTURE — RV32 header, split and two-sided coalescing
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class "01 Block header" as HEADER {
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next : BlockLink_t*
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size : size_t
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raw sizeof = 8 bytes on RV32
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aligned xHeapStructSize = 16
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}
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class "Allocated block" as ALLOC {
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02 A: header + 24 byte request
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aligned total = 48 bytes
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payload begins after header
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}
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class "03 Free remainder" as REM {
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own header
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free = 4032 bytes after A
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}
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HEADER *-- ALLOC : precedes payload
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ALLOC -down-> REM : first-fit + split
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class "04 Address-ordered free list" as LIST {
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previous < inserted < current
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A < B < C+tail
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}
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class "05 Previous / left neighbour" as LEFT {
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previous + previous.size == inserted
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merge previous first
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}
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class "06 Next / right neighbour" as RIGHT {
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merged + merged.size == current
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merge next second
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}
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REM -down-> LIST : insert by address
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LIST -down-> LEFT : heap_4 tests first
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LEFT -down-> RIGHT : then tests next
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note right of LIST
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Address order exposes both physical
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neighbours without scanning the arena.
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end note
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@enduml
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