circuitpython/ports/atmel-samd/boards/samd21x18-bootloader-external-flash.ld

/*
    GNU linker script for SAMD21x18 (256K flash, 32K RAM)
*/

/* Specify the memory areas */
MEMORY
{
    /* Leave 8KiB for the bootloader and 256b for user config. */
    FLASH (rx) : ORIGIN = 0x00000000 + 8K, LENGTH = 256K - 8K - 256
    RAM (xrw)  : ORIGIN = 0x20000000, LENGTH = 32K /* 32 KiB RAM */
}

/* top end of the stack */
/* stack must be double-word (8 byte) aligned */
_estack = ORIGIN(RAM) + LENGTH(RAM) - 8;
_bootloader_dbl_tap = _estack;

/* define output sections */
SECTIONS
{
    /* The program code and other data goes into FLASH */
    .text :
    {
        . = ALIGN(4);
        _sfixed = .;
        KEEP(*(.vectors)) /* isr vector table */
        *(.text)           /* .text sections (code) */
        *(.text*)          /* .text* sections (code) */
        *(.rodata)         /* .rodata sections (constants, strings, etc.) */
        *(.rodata*)        /* .rodata* sections (constants, strings, etc.) */

        . = ALIGN(4);
    } >FLASH

    .ARM.exidx :
    {
        *(.ARM.exidx*)
        *(.gnu.linkonce.armexidx.*)
        _etext = .;        /* define a global symbol at end of code */
        _sidata = .;       /* start of .data section */
    } > FLASH

    /* This is the initialized data section
    The program executes knowing that the data is in the RAM
    but the loader puts the initial values in the FLASH (inidata).
    It is one task of the startup to copy the initial values from FLASH to RAM. */
    .data : AT ( _etext )
    {
        . = ALIGN(4);
        _srelocate = .;        /* create a global symbol at data start; used by startup code in order to initialise the .data section in RAM */
        *(.ramfunc)
        *(.ramfunc*)
        *(.data)           /* .data sections */
        *(.data*)          /* .data* sections */

        . = ALIGN(4);
        _erelocate = .;        /* define a global symbol at data end; used by startup code in order to initialise the .data section in RAM */
    } >RAM

    /* Uninitialized data section */
    .bss :
    {
        . = ALIGN(4);
        _sbss = .;
        _szero = .;         /* define a global symbol at bss start; used by startup code */
        *(.bss)
        *(.bss*)
        *(COMMON)

        . = ALIGN(4);
        _ezero = .;         /* define a global symbol at bss end; used by startup code */
        _ebss = .;
    } >RAM

    /* this just checks there is enough RAM for a minimal stack */
    .stack :
    {
        . = ALIGN(4);
        . = . + 2K; /* Reserve a minimum of 2K for the stack. */
        . = ALIGN(4);
    } >RAM

    .ARM.attributes 0 : { *(.ARM.attributes) }
}