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Initial version of samples added
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‎README.md

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@@ -104,49 +104,9 @@ PATH=${INSTALL_ROOT_DIR}/LLVMEmbeddedToolchainForArm-$VERSION/bin:$PATH
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clang --config armv6m-none-eabi_nosys -T device.ld -o example example.c
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```
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### Test the toolchain
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Simple examples built with the toolchain can be run with [QEMU User space emulator](https://www.qemu.org/docs/master/user/main.html) making use of semihosting for input and output as follows.
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_Note: More complex bare-metal examples may need to use [QEMU Arm System emulator](https://www.qemu.org/docs/master/system/target-arm.html)._
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Assuming this example code in `hello.c` file:
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```
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#include <stdio.h>
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int main()
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{
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printf("Hello Embedded LLVM!\n");
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return 0;
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}
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```
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Build the example:
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```
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$ PATH=${INSTALL_ROOT_DIR}/LLVMEmbeddedToolchainForArm-$VERSION/bin:$PATH
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$ clang --config armv6m-none-eabi_rdimon -g -o hello hello.c
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```
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Run the example with QEMU:
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```
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$ qemu-arm -cpu cortex-m0 hello
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Hello Embedded LLVM!
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```
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Debug the example with GDB:
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Console 1: start QEMU in debug mode:
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```
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$ qemu-arm -cpu cortex-m0 -g 1234 hello
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```
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Console 2: attach to QEMU with GDB provided by the [GNU Arm Embedded Toolchain](https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/gnu-rm/downloads):
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```
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$ arm-none-eabi-gdb hello
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(gdb) target remote :1234
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```
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See the `samples` folder for sample code and instructions on building, running and debugging.
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## Known limitations
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* Depending on the state of the components, build errors may occur when ``VERSION=HEAD`` is used.

‎samples/.gitignore

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**/*.elf
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**/*.hex

‎samples/Makefile.conf

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#
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# Copyright (c) 2020, Arm Limited and affiliates.
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# SPDX-License-Identifier: Apache-2.0
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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ifndef VERSION
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VERSION=0.1
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endif
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BIN_PATH=../../../LLVMEmbeddedToolchainForArm-${VERSION}/bin/

‎samples/README.md

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Samples of LLVM Embedded Toolchain for Arm
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# Directory structure
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* `ldscripts` - Linker scripts used by samples.
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* `startup` - Startup code used by samples.
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* `src` - Sample source code, Makefile and description, each sub-directory is a separate sample.

‎samples/ldscripts/microbit.ld

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/* Linker script to configure memory regions.
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* Need modifying for a specific board.
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* FLASH.ORIGIN: starting address of flash
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* FLASH.LENGTH: length of flash
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* RAM.ORIGIN: starting address of RAM bank 0
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* RAM.LENGTH: length of RAM bank 0
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*/
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MEMORY
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{
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FLASH (rx) : ORIGIN = 0x00000000, LENGTH = 0x40000
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RAM (rwx) : ORIGIN = 0x20000000, LENGTH = 0x4000
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}
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/* Linker script to place sections and symbol values. Should be used together
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* with other linker script that defines memory regions FLASH and RAM.
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* It references following symbols, which must be defined in code:
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* Reset_Handler : Entry of reset handler
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*
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* It defines following symbols, which code can use without definition:
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* __exidx_start
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* __exidx_end
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* __copy_table_start__
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* __copy_table_end__
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* __zero_table_start__
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* __zero_table_end__
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* __etext
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* __data_start__
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* __preinit_array_start
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* __preinit_array_end
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* __init_array_start
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* __init_array_end
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* __fini_array_start
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* __fini_array_end
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* __data_end__
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* __bss_start__
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* __bss_end__
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* __end__
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* end
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* __HeapLimit
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* __StackLimit
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* __StackTop
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* __stack
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*/
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ENTRY(Reset_Handler)
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SECTIONS
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{
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.text :
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{
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KEEP(*(.isr_vector))
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*(.text*)
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KEEP(*(.init))
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KEEP(*(.fini))
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/* .ctors */
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*crtbegin.o(.ctors)
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*crtbegin?.o(.ctors)
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*(EXCLUDE_FILE(*crtend?.o *crtend.o) .ctors)
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*(SORT(.ctors.*))
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*(.ctors)
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/* .dtors */
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*crtbegin.o(.dtors)
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*crtbegin?.o(.dtors)
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*(EXCLUDE_FILE(*crtend?.o *crtend.o) .dtors)
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*(SORT(.dtors.*))
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*(.dtors)
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KEEP(*(.eh_frame*))
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} > FLASH
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.rodata :
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{
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*(.rodata .rodata.*)
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} > FLASH
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.ARM.extab :
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{
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*(.ARM.extab* .gnu.linkonce.armextab.*)
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} > FLASH
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__exidx_start = .;
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.ARM.exidx :
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{
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*(.ARM.exidx .ARM.exidx* .gnu.linkonce.armexidx.*)
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} > FLASH
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__exidx_end = .;
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/* To copy multiple ROM to RAM sections,
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* uncomment .copy.table section and,
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* define __STARTUP_COPY_MULTIPLE in startup_ARMCMx.S */
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/*
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.copy.table :
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{
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. = ALIGN(4);
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__copy_table_start__ = .;
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LONG (__etext)
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LONG (__data_start__)
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LONG (__data_end__ - __data_start__)
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LONG (__etext2)
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LONG (__data2_start__)
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LONG (__data2_end__ - __data2_start__)
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__copy_table_end__ = .;
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} > FLASH
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*/
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/* To clear multiple BSS sections,
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* uncomment .zero.table section and,
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* define __STARTUP_CLEAR_BSS_MULTIPLE in startup_ARMCMx.S */
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/*
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.zero.table :
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{
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. = ALIGN(4);
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__zero_table_start__ = .;
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LONG (__bss_start__)
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LONG (__bss_end__ - __bss_start__)
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LONG (__bss2_start__)
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LONG (__bss2_end__ - __bss2_start__)
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__zero_table_end__ = .;
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} > FLASH
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*/
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/* Location counter can end up 2byte aligned with narrow Thumb code but
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__etext is assumed by startup code to be the LMA of a section in RAM
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which must be 4byte aligned */
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__etext = ALIGN (4);
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.data : AT (__etext)
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{
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__data_start__ = .;
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*(vtable)
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*(.data*)
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. = ALIGN(4);
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/* preinit data */
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PROVIDE_HIDDEN (__preinit_array_start = .);
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KEEP(*(.preinit_array))
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PROVIDE_HIDDEN (__preinit_array_end = .);
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. = ALIGN(4);
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/* init data */
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PROVIDE_HIDDEN (__init_array_start = .);
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KEEP(*(SORT(.init_array.*)))
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KEEP(*(.init_array))
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PROVIDE_HIDDEN (__init_array_end = .);
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. = ALIGN(4);
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/* finit data */
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PROVIDE_HIDDEN (__fini_array_start = .);
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KEEP(*(SORT(.fini_array.*)))
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KEEP(*(.fini_array))
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PROVIDE_HIDDEN (__fini_array_end = .);
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KEEP(*(.jcr*))
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. = ALIGN(4);
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/* All data end */
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__data_end__ = .;
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} > RAM
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.bss :
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{
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. = ALIGN(4);
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__bss_start__ = .;
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*(.bss*)
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*(COMMON)
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. = ALIGN(4);
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__bss_end__ = .;
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} > RAM
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.heap (COPY):
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{
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__end__ = .;
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PROVIDE(end = .);
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*(.heap*)
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__HeapLimit = .;
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} > RAM
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/* .stack_dummy section doesn't contains any symbols. It is only
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* used for linker to calculate size of stack sections, and assign
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* values to stack symbols later */
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.stack_dummy (COPY):
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{
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*(.stack*)
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} > RAM
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/* Set stack top to end of RAM, and stack limit move down by
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* size of stack_dummy section */
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__StackTop = ORIGIN(RAM) + LENGTH(RAM);
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__StackLimit = __StackTop - SIZEOF(.stack_dummy);
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PROVIDE(__stack = __StackTop);
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/* Check if data + heap + stack exceeds RAM limit */
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ASSERT(__StackLimit >= __HeapLimit, "region RAM overflowed with stack")
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}

‎samples/src/baremetal-semihosting/Makefile

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#
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# Copyright (c) 2020, Arm Limited and affiliates.
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# SPDX-License-Identifier: Apache-2.0
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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include ../../Makefile.conf
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build: hello.elf
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hello.elf: *.c
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$(BIN_PATH)clang --config armv6m-none-eabi_rdimon_baremetal -g -T ../../ldscripts/microbit.ld -o hello.elf ../../startup/startup_ARMCM0.S $^
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%.hex: %.elf
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$(BIN_PATH)llvm-objcopy -O ihex $< $@
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run: hello.hex
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# -m option is a workaround to ensure correct initialization of semihosting
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qemu-system-arm -M microbit -semihosting -nographic -device loader,file=$< -m 1073741824k
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debug: hello.hex
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qemu-system-arm -M microbit -semihosting -nographic -device loader,file=$< -m 1073741824k -s -S
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clean:
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rm *.elf *.hex
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.PHONY: clean run debug

‎samples/src/baremetal-semihosting/README.md

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This sample shows how to use semihosting with [QEMU Arm System emulator](https://www.qemu.org/docs/master/system/target-arm.html) targeting the [micro:bit board model](https://www.qemu.org/2019/05/22/microbit/).
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It uses the startup code and the linker script file from the GNU Arm Embedded Toolchain samples.
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Usage:
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* `VERSION=0.1 make build` to build the sample.
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* `VERSION=0.1 make run` to run the the sample with QEMU Arm System emulator.
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* `VERSION=0.1 make debug` to run the the sample with QEMU Arm System emulator with GDB server listening on the default port 1234.
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To debug attach to QEMU with GDB provided by the [GNU Arm Embedded Toolchain](https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/gnu-rm/downloads):
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```
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$ arm-none-eabi-gdb hello.elf
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(gdb) target remote :1234
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```

‎samples/src/baremetal-semihosting/hello.c

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#include <stdio.h>
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int main(void) {
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printf("Hello World!\n");
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return 0;
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}
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void SystemInit() {}

‎samples/src/baremetal-uart/Makefile

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#
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# Copyright (c) 2020, Arm Limited and affiliates.
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# SPDX-License-Identifier: Apache-2.0
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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include ../../Makefile.conf
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build: hello.elf
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hello.elf: *.c
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$(BIN_PATH)clang --config armv6m-none-eabi_nosys -g -T ../../ldscripts/microbit.ld -o hello.elf ../../startup/startup_ARMCM0.S $^
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%.hex: %.elf
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$(BIN_PATH)llvm-objcopy -O ihex $< $@
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run: hello.hex
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qemu-system-arm -M microbit -semihosting -nographic -device loader,file=$< -m 1073741824k
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debug: hello.hex
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qemu-system-arm -M microbit -semihosting -nographic -device loader,file=$< -m 1073741824k -s -S
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clean:
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rm *.elf *.hex
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.PHONY: clean run debug

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