5eb9f9d060
Commit efbf08266b moved _estack in order to ensure 8-byte alignment
of the stack, but the address of _bootloader_dbl_tap must remain
right at the end of SRAM.
I verified by reading the source that the 4-byte-aligned address is
used for all samd21 / samd51 boards in
adafruit/circuitpython@efbf08266b. However, I only tested on
trinket_m0.
Closes: #739
85 lines
2.6 KiB
Plaintext
85 lines
2.6 KiB
Plaintext
/*
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GNU linker script for SAMD21x18 (256K flash, 32K RAM)
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*/
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/* Specify the memory areas */
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MEMORY
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{
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/* Leave 8KiB for the bootloader and 256b for user config. */
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FLASH (rx) : ORIGIN = 0x00000000 + 8K, LENGTH = 256K - 8K - 256
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RAM (xrw) : ORIGIN = 0x20000000, LENGTH = 32K /* 32 KiB RAM */
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}
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/* top end of the stack */
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/* stack must be double-word (8 byte) aligned */
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_estack = ORIGIN(RAM) + LENGTH(RAM) - 8;
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_bootloader_dbl_tap = ORIGIN(RAM) + LENGTH(RAM) - 4;
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/* define output sections */
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SECTIONS
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{
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/* The program code and other data goes into FLASH */
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.text :
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{
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. = ALIGN(4);
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_sfixed = .;
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KEEP(*(.vectors)) /* isr vector table */
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*(.text) /* .text sections (code) */
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*(.text*) /* .text* sections (code) */
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*(.rodata) /* .rodata sections (constants, strings, etc.) */
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*(.rodata*) /* .rodata* sections (constants, strings, etc.) */
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. = ALIGN(4);
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} >FLASH
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.ARM.exidx :
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{
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*(.ARM.exidx*)
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*(.gnu.linkonce.armexidx.*)
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_etext = .; /* define a global symbol at end of code */
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_sidata = .; /* start of .data section */
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} > FLASH
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/* This is the initialized data section
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The program executes knowing that the data is in the RAM
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but the loader puts the initial values in the FLASH (inidata).
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It is one task of the startup to copy the initial values from FLASH to RAM. */
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.data : AT ( _etext )
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{
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. = ALIGN(4);
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_srelocate = .; /* create a global symbol at data start; used by startup code in order to initialise the .data section in RAM */
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*(.ramfunc)
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*(.ramfunc*)
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*(.data) /* .data sections */
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*(.data*) /* .data* sections */
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. = ALIGN(4);
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_erelocate = .; /* define a global symbol at data end; used by startup code in order to initialise the .data section in RAM */
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} >RAM
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/* Uninitialized data section */
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.bss :
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{
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. = ALIGN(4);
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_sbss = .;
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_szero = .; /* define a global symbol at bss start; used by startup code */
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*(.bss)
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*(.bss*)
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*(COMMON)
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. = ALIGN(4);
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_ezero = .; /* define a global symbol at bss end; used by startup code */
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_ebss = .;
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} >RAM
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/* this just checks there is enough RAM for a minimal stack */
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.stack :
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{
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. = ALIGN(4);
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. = . + 2K; /* Reserve a minimum of 2K for the stack. */
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. = ALIGN(4);
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} >RAM
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.ARM.attributes 0 : { *(.ARM.attributes) }
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}
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