freertos_drivers/nxp/stack_malloc.c

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#include <string.h>
#include <stdlib.h>
#include "utils/blinker.h"
#include "utils/constants.hxx"
 
extern char __ETHRAM_segment_start__;
static char* sstack_start = &__ETHRAM_segment_start__;
extern char __stacks_min__;
 
void* usb_malloc(unsigned long length);
 
DECLARE_CONST(use_separate_stack_segment);
 
void* stack_malloc(unsigned long length)
{
    if (config_use_separate_stack_segment() == CONSTANT_TRUE) {
        char* old_stack_start = sstack_start;
        char* new_stack_start = sstack_start + length;
        if (new_stack_start > &__stacks_min__)
        {
            diewith(BLINK_DIE_OUTOFMEMSTACK);
        }
        sstack_start = new_stack_start;
        return old_stack_start;
    } else {
        return usb_malloc(length);
    }
}
 
extern char __USBRAM_segment_start__;
extern char __USBRAM_segment_end__;
static char* ublock_start = &__USBRAM_segment_start__;
 
void* usb_malloc(unsigned long length)
{
    // Aligns to 4 bytes.
    length += 3; length &= ~3;
    char* old_ublock_start = ublock_start;
    char* new_ublock_start = ublock_start + length;
    if (new_ublock_start > &__USBRAM_segment_end__)
    {
        diewith(BLINK_DIE_OUTOFMEMSTACK);
    }
    ublock_start = new_ublock_start;
    return old_ublock_start;
}
 
void *buffer_malloc(size_t length)
{
    /* We do a trick here to ensure that the compiler will output a stack frame
     * for this function. We want to avoid tail-chain optimization in this
     * function or else it disappears from the stack traces done for memory
     * tracing. */
    void *volatile v = usb_malloc(length);
    return v;
}