gcc_arm.ld

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/* Linker script to configure memory regions. */
MEMORY
{
  FLASH (rx) : ORIGIN = 0x00000000, LENGTH = 0x40000   /* 256k */
  RAM (rwx)  : ORIGIN = 0x20000000, LENGTH = 0x08000   /*  32k */
}

/* Library configurations */
GROUP(libgcc.a libc.a libm.a libnosys.a)

/* Linker script to place sections and symbol values. Should be used together
 * with other linker script that defines memory regions FLASH and RAM.
 * It references following symbols, which must be defined in code:
 *   Reset_Handler : Entry of reset handler
 * 
 * It defines following symbols, which code can use without definition:
 *   __exidx_start
 *   __exidx_end
 *   __etext
 *   __data_start__
 *   __preinit_array_start
 *   __preinit_array_end
 *   __init_array_start
 *   __init_array_end
 *   __fini_array_start
 *   __fini_array_end
 *   __data_end__
 *   __bss_start__
 *   __bss_end__
 *   __end__
 *   end
 *   __HeapLimit
 *   __StackLimit
 *   __StackTop
 *   __stack
 */
ENTRY(Reset_Handler)

SECTIONS
{
        .text :
        {
                KEEP(*(.isr_vector))
                *(.text*)

                KEEP(*(.init))
                KEEP(*(.fini))

                /* .ctors */
                *crtbegin.o(.ctors)
                *crtbegin?.o(.ctors)
                *(EXCLUDE_FILE(*crtend?.o *crtend.o) .ctors)
                *(SORT(.ctors.*))
                *(.ctors)

                /* .dtors */
                *crtbegin.o(.dtors)
                *crtbegin?.o(.dtors)
                *(EXCLUDE_FILE(*crtend?.o *crtend.o) .dtors)
                *(SORT(.dtors.*))
                *(.dtors)

                *(.rodata*)

                KEEP(*(.eh_frame*))
        } > FLASH

        .ARM.extab : 
        {
                *(.ARM.extab* .gnu.linkonce.armextab.*)
        } > FLASH

        __exidx_start = .;
        .ARM.exidx :
        {
                *(.ARM.exidx* .gnu.linkonce.armexidx.*)
        } > FLASH
        __exidx_end = .;

        __etext = .;
                
        .data : AT (__etext)
        {
                __data_start__ = .;
                *(vtable)
                *(.data*)

                . = ALIGN(4);
                /* preinit data */
                PROVIDE_HIDDEN (__preinit_array_start = .);
                KEEP(*(.preinit_array))
                PROVIDE_HIDDEN (__preinit_array_end = .);

                . = ALIGN(4);
                /* init data */
                PROVIDE_HIDDEN (__init_array_start = .);
                KEEP(*(SORT(.init_array.*)))
                KEEP(*(.init_array))
                PROVIDE_HIDDEN (__init_array_end = .);


                . = ALIGN(4);
                /* finit data */
                PROVIDE_HIDDEN (__fini_array_start = .);
                KEEP(*(SORT(.fini_array.*)))
                KEEP(*(.fini_array))
                PROVIDE_HIDDEN (__fini_array_end = .);

                . = ALIGN(4);
                /* All data end */
                __data_end__ = .;

        } > RAM

        .bss :
        {
                __bss_start__ = .;
                *(.bss*)
                *(COMMON)
                __bss_end__ = .;
        } > RAM
        
        .heap :
        {
                __end__ = .;
                end = __end__;
                *(.heap*)
                __HeapLimit = .;
        } > RAM

        /* .stack_dummy section doesn't contains any symbols. It is only
         * used for linker to calculate size of stack sections, and assign
         * values to stack symbols later */
        .stack_dummy :
        {
                *(.stack)
        } > RAM

        /* Set stack top to end of RAM, and stack limit move down by
         * size of stack_dummy section */
        __StackTop = ORIGIN(RAM) + LENGTH(RAM);
        __StackLimit = __StackTop - SIZEOF(.stack_dummy);
        PROVIDE(__stack = __StackTop);
        
        /* Check if data + heap + stack exceeds RAM limit */
        ASSERT(__StackLimit >= __HeapLimit, "region RAM overflowed with stack")
}