Core Memory Manager

Collaboration diagram for Core Memory Manager:

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Detailed Description

Core Memory Manager related APIs and services.

Operation mode

The core memory manager is a simplified allocator that only allows to allocate memory blocks without the possibility to free them.
This allocator is meant as a memory blocks provider for the other allocators such as:

• C-Runtime allocator (through a compiler specific adapter module).
• Heap allocator (see Heaps).
• Memory pools allocator (see Memory Pools).

By having a centralized memory provider the various allocators can coexist and share the main memory.
This allocator, alone, is also useful for very simple applications that just require a simple way to get memory blocks.

Precondition:

In order to use the core memory manager APIs the CH_USE_MEMCORE option must be enabled in chconf.h.

Functions
void	_core_init (void)
	Low level memory manager initialization.
void *	chCoreAlloc (size_t size)
	Allocates a memory block.
void *	chCoreAllocI (size_t size)
	Allocates a memory block.
size_t	chCoreStatus (void)
	Core memory status.
Alignment support macros
#define	MEM_ALIGN_SIZE   sizeof(stkalign_t)
	Alignment size constant.
#define	MEM_ALIGN_MASK   (MEM_ALIGN_SIZE - 1)
	Alignment mask constant.
#define	MEM_ALIGN_PREV(p)   ((size_t)(p) & ~MEM_ALIGN_MASK)
	Alignment helper macro.
#define	MEM_ALIGN_NEXT(p)   MEM_ALIGN_PREV((size_t)(p) + MEM_ALIGN_MASK)
	Alignment helper macro.
#define	MEM_IS_ALIGNED(p)   (((size_t)(p) & MEM_ALIGN_MASK) == 0)
	Returns whatever a pointer or memory size is aligned to the type align_t.
Typedefs
typedef void *(*	memgetfunc_t )(size_t size)
	Memory get function.

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Function Documentation

void _core_init

(

void

)

Low level memory manager initialization.

Function Class:

Not an API, this function is for internal use only.

Definition at line 59 of file chmemcore.c.

References CH_MEMCORE_SIZE, MEM_ALIGN_NEXT, MEM_ALIGN_PREV, and MEM_ALIGN_SIZE.

Referenced by chSysInit().

void * chCoreAlloc

(

size_t

size

)

Allocates a memory block.

The size of the returned block is aligned to the alignment type so it is not possible to allocate less than MEM_ALIGN_SIZE.

Parameters:

[in]

size

the size of the block to be allocated

Returns:

A pointer to the allocated memory block.

Return values:

NULL	allocation failed, core memory exhausted.

Function Class:

Normal API, this function can be invoked by regular system threads but not from within a lock zone.

Definition at line 84 of file chmemcore.c.

References chCoreAllocI(), chSysLock, and chSysUnlock.

Referenced by _heap_init().

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void * chCoreAllocI

(

size_t

size

)

Allocates a memory block.

The size of the returned block is aligned to the alignment type so it is not possible to allocate less than MEM_ALIGN_SIZE.

Parameters:

[in]

size

the size of the block to be allocated.

Returns:

A pointer to the allocated memory block.

Return values:

NULL	allocation failed, core memory exhausted.

Function Class:

This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 105 of file chmemcore.c.

References chDbgCheckClassI(), and MEM_ALIGN_NEXT.

Referenced by chCoreAlloc().

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size_t chCoreStatus

(

void

)

Core memory status.

Returns:

The size, in bytes, of the free core memory.

Function Class:

Normal API, this function can be invoked by regular system threads but not from within a lock zone.

Definition at line 125 of file chmemcore.c.

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Define Documentation

#define MEM_ALIGN_SIZE   sizeof(stkalign_t)

Alignment size constant.

Definition at line 45 of file chmemcore.h.

Referenced by _core_init().

#define MEM_ALIGN_MASK   (MEM_ALIGN_SIZE - 1)

Alignment mask constant.

Definition at line 50 of file chmemcore.h.

#define MEM_ALIGN_PREV

(

p

)

((size_t)(p) & ~MEM_ALIGN_MASK)

Alignment helper macro.

Definition at line 55 of file chmemcore.h.

Referenced by _core_init().

#define MEM_ALIGN_NEXT

(

p

)

MEM_ALIGN_PREV((size_t)(p) + MEM_ALIGN_MASK)

Alignment helper macro.

Definition at line 60 of file chmemcore.h.

Referenced by _core_init(), chCoreAllocI(), and chHeapAlloc().

#define MEM_IS_ALIGNED

(

p

)

(((size_t)(p) & MEM_ALIGN_MASK) == 0)

Returns whatever a pointer or memory size is aligned to the type align_t.

Definition at line 66 of file chmemcore.h.

Referenced by chHeapInit().

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Typedef Documentation

typedef void*(* memgetfunc_t)(size_t size)

Memory get function.

Note:

This type must be assignment compatible with the chMemAlloc() function.

Definition at line 37 of file chmemcore.h.