ESP32/components/u8g2/sys/arm/lpc824/blink/lpc824.ld

/* source: gcc-arm-none-eabi-4_7-2013q1/share/gcc-arm-none-eabi/samples/ldscripts/mem.ld */

/* Linker script to configure memory regions. 
 * Need modifying for a specific board. 
 *   FLASH.ORIGIN: starting address of flash
 *   FLASH.LENGTH: length of flash
 *   RAM.ORIGIN: starting address of RAM bank 0
 *   RAM.LENGTH: length of RAM bank 0
 */
MEMORY
{
  /* LPC82x User Manual Page 8 */
  FLASH (rx) : ORIGIN = 0x0, LENGTH = 0x8000 /* 32K for LPC824 */
  RAM (rwx) : ORIGIN = 0x10000000, LENGTH = 0x2000 /* 8K for LPC824 */
}

/* source: gcc-arm-none-eabi-4_7-2013q1/share/gcc-arm-none-eabi/samples/ldscripts/sections.ld */

/* 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 point */
ENTRY(Reset_Handler)

/* extern declaration so that the value appears correctly for the LPC checksum calculation */
EXTERN(NMI_Handler)
EXTERN(HardFault_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 = .);

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

	} > RAM

	.bss :
	{
		. = ALIGN(4);
		__bss_start__ = .;
		*(.bss*)
		*(COMMON)
		. = ALIGN(4);
		__bss_end__ = .;
	} > RAM
	
	.heap (COPY):
	{
		__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 (COPY):
	{
		*(.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")
	
	/* 
	  http://www.lpcware.com/content/forum/lpc1788-flash-signature-generation
	  Section 3.5.2/page 12 of the LPC82x User Manual
	
	  Linker works with even addresses, however to indicate thumb address mode, 
	  the lowest bit of the address is set to one. For the checksum calculation we
	  only have the even addresses, however later in the isr table the compiler will
	  store the odd addresses for the three handler subprocedures if compiled in
	  thumb mode. Because of this, 3 is added to consider the three odd handler calls. 
	*/	
	LPC_checksum = 0- (__StackTop + Reset_Handler + NMI_Handler + HardFault_Handler + 3 /* three entries */);
}