memory.cpp File Reference

Implements the free memory checking functions. More...

#include "util/debug/memory.hpp"
#include <WProgram.h>

Include dependency graph for memory.cpp:

Classes
struct	AvrFreeListEntry
	Internal structure used by avr-libc to manage the free memory list. More...

Typedefs
using	AvrHeapStart = unsigned int

Functions
AvrHeapStart avrHeapStart	asm ("__heap_start")
void *avrBreakValue	asm ("__brkval")
AvrFreeListEntry *avrFreeListHead	asm ("__flp")
auto	freeListSize () -> size_t
	Calculate the total payload currently stored in avr-libc's free list.
auto	freeMemory () -> size_t
	Estimate the amount of free SRAM currently available on the MCU.

Detailed Description

Implements the free memory checking functions.

Author

Jacopo Labardi (labodj)

Copyright 2026 Jacopo Labardi

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Function Documentation

freeListSize()

auto freeListSize

(

)

-> size_t

Calculate the total payload currently stored in avr-libc's free list.

This helper walks the allocator free list so fragmented heap blocks contribute to the final free-memory estimate returned by freeMemory().

Returns

size_t Total bytes available inside the allocator free list.

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freeMemory()

auto freeMemory

(

)

-> size_t

Estimate the amount of free SRAM currently available on the MCU.

The implementation combines the stack-to-heap gap with the bytes stored in avr-libc's free list so fragmented allocations are counted too.

Returns

size_t Estimated free SRAM in bytes.

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