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40 lines
1.0 KiB
Markdown
40 lines
1.0 KiB
Markdown
---
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title: "memory_model"
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---
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{{< callout type="info">}}
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Header: `memory_model.h`
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{{< /callout >}}
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This header defines enumerations and type lookups for supporting various memory models for the ETL.
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These allow template classes to use optimally sized variables for the model.
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For example, if a container will never have more than 256 elements then indexes and counts may be contained in an 8 bit type.
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## memory_model
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A user type that defines values for four different memory models.
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`MEMORY_MODEL_SMALL`
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`MEMORY_MODEL_MEDIUM`
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`MEMORY_MODEL_LARGE`
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`MEMORY_MODEL_HUGE`
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## Example
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```cpp
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etl::memory_model::MEMORY_MODEL_LARGE
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```
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## size_type_lookup
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A type lookup template that defines a type that equates to the size type for memory model.
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```cpp
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using size_type = typename etl::size_type_lookup<etl::memory_model::MEMORY_MODEL_LARGE>::type;
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```
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The defined types are:
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```cpp
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MEMORY_MODEL_SMALL uint_least8_t
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MEMORY_MODEL_MEDIUM uint_least16_t
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MEMORY_MODEL_LARGE uint_least32_t
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MEMORY_MODEL_HUGE uint_least64_t
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```
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