armv7_helloworld

simple bare metal ARMv7 example
git clone https://0xdd.org/code/armv7_helloworld.git
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layout.lds (1025B)


      1 /*
      2 2018 David DiPaola
      3 licensed under CC0 (public domain, see https://creativecommons.org/publicdomain/zero/1.0/)
      4 */
      5 
      6 /* code entry point */
      7 ENTRY(main)
      8 
      9 /* memory regions (see QEMU:vexpress.c) */
     10 MEMORY {
     11 	MAP_IO_UART0 : ORIGIN = 0x1C090000, LENGTH = 0x00000400 /* 1KB */
     12 	MAP_DRAM     : ORIGIN = 0x80000000, LENGTH = 0x80000000 /* 2GB */
     13 }
     14 
     15 /* ELF binary sections */
     16 SECTIONS {
     17 	/* NOTE `SUBALIGN` is used with the `gcc` flags `-ffunction-sections` and `-fdata-sections` to ensure each function and piece of data are properly aligned */
     18 
     19 	/* IO: UART0 */
     20 	SECTION_IO_UART0 ORIGIN(MAP_IO_UART0): SUBALIGN(4) {
     21 		*(.data)
     22 		*(.bss)
     23 	} >MAP_IO_UART0
     24 
     25 	/* DRAM */
     26 	.text ORIGIN(MAP_DRAM) + 0 : SUBALIGN(4) {  /* code and read-only data */
     27 		*(.text.startup.main)
     28 		*(.text)
     29 		*(.rodata)
     30 	} >MAP_DRAM
     31 	.data ORIGIN(MAP_DRAM) + SIZEOF(.text) : SUBALIGN(4) {  /* initialized data */
     32 		*(.data)
     33 	} >MAP_DRAM
     34 	.bss ORIGIN(MAP_DRAM) + SIZEOF(.text) + SIZEOF(.data) : SUBALIGN(4) {  /* uninitialized data */
     35 		*(.bss)
     36 	} >MAP_DRAM
     37 
     38 }
     39