Import Mbed OS hard-float snapshot

targets/TARGET_ARM_SSG/TARGET_CM3DS_MPS2/README.md

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+# Cortex-M3 Design Start Eval package example on MPS2+ board
+
+This folder includes the port of Mbed OS on the example system of the Cortex-M3
+Design Start Eval package. This example is implemented in FPGA on the MPS2+
+board. Please see this target's [Mbed page](https://os.mbed.com/platforms/ARM-CM3DS/)
+for more information.
+For convenience, this target is called **CM3DS**.
+
+## Compiling
+
+The target name is `ARM_CM3DS_MPS2`. You can compile Mbed OS
+projects for CM3DS with:
+
+```bash
+mbed compile -t COMPILER -m ARM_CM3DS_MPS2
+```
+
+Mbed OS supports the following compilers (replace `COMPILER` with):
+
+* `ARM` for Arm Compiler version 5.
+* `GCC_ARM` for GNU Compiler for Arm.
+* `IAR` for IAR compiler.
+
+## Running
+
+Because of the new memory configuration introduced in commit `CM3DS: switch to
+larger memories for code and data`, it
+has become easier (and portable among all compilers) to use `.elf` files
+instead of `.bin`. `.elf` files are now the default for CM3DS projects, and compilation
+generates only them.
+For `.elf` files to work, you need **at least version 2.2.5** of the MPS2+
+firmware. For more information, please see the [firmware version 2.2.6 and instructions on how to put it
+in the MPS2+ board](https://community.arm.com/processors/designstart/f/discussions/9727/mps2-firmware-for-mbed).
+
+## Testing
+
+If you want to execute the Mbed OS greentea tests on CM3DS, you need
+**at least firmware version 2.2.6**.
+
+* `mbedls` does not automatically recognize which serial port is linked to the
+board. Check it manually, and create a file named `mbedls.json` containing
+(at the same level than where you execute all commands):
+
+```bash
+{
+    "50040200074D652F3828F333": {
+        "serial_port": "/dev/ttyUSB0"
+    }
+}
+```
+
+Replace `/dev/ttyUSB0` with your correct serial port
+(something like `COM6` on Windows).
+
+* `mbedls` does not link CM3DS target ID with its name, so execute the command:
+
+```bash
+mbedls --mock 5004:ARM_CM3DS_MPS2
+```
+
+* You can now compile and run the tests:
+
+```bash
+mbed test -m ARM_CM3DS_MPS2 -t COMPILER
+```