✨: Add RIOT example

.gitignore

@@ -16,6 +16,8 @@ Cargo.lock
 
 *.hex
 *.elf
+*.bin
+RIOT_App/app/bin
 
 # Added by cargo
 

.gitmodules

@@ -1,3 +1,7 @@
 [submodule "tests/src"]
 	path = tests/src
 	url = git@github.com:riscv-software-src/riscv-tests.git
+[submodule "RIOT_App/RIOT"]
+	path = RIOT_App/RIOT
+	url = https://github.com/RIOT-OS/RIOT.git
+	shallow = true

Cargo.toml

@@ -1,5 +1,5 @@
 [package]
-name = "rv"
+name = "triops"
 version = "0.1.0"
 edition = "2021"
 

RIOT_App/README.md

@@ -0,0 +1,69 @@
+# RIOT for TRIOPS
+
+The [RIOT](https://github.com/RIOT-OS/RIOT) OS supports the Hifive1b board, which is emulated by TRIOPS.
+All you need to do is building a RIOT app for that board and load the resulting binary file into TRIOPS.
+To setup your system for RIOT development, please refer to the [Getting Started](https://guide.riot-os.org/getting-started/installing/) guide of RIOT.
+The tl;dr is that you will need GCC (`riscv64-unknown-elf`), binutils, and newlib.
+
+Because it is easy to use RIOT with external apps, TRIOPS comes with an example app provided in the `app/` folder.
+The `Makefile` in the example configures RIOT to:
+
+* target the Hifive1b board
+* set the app name to `triops_app`
+* use the emulator for running the app
+* which RIOT modules to include
+
+While the `main.c` prints a hello-world and starts the RIOT shell.
+
+## Building the RIOT example app
+
+1. Clone RIOT. Because it is a git submodule, you can fetch it right here:
+```sh
+git submodule update
+```
+
+2. Enter the `app/` directory and run gnu `make`
+```sh
+cd app/ && make
+```
+
+3. You will see RIOTs build process and the result binary `triops_app.elf`. It should look something like this:
+```txt
+Building application "triops_app" for "hifive1b" with CPU "fe310".
+
+make -C /foo/triops/RIOT_App/RIOT/pkg/mpaland-printf/ 
+make -C /foo/triops/RIOT_App/RIOT/build/pkg/mpaland-printf -f /foo/triops/RIOT_App/RIOT/pkg/mpaland-printf/mpaland-printf.mk
+make -C /foo/triops/RIOT_App/RIOT/boards
+make -C /foo/triops/RIOT_App/RIOT/boards/common/init
+make -C /foo/triops/RIOT_App/RIOT/boards/hifive1b
+make -C /foo/triops/RIOT_App/RIOT/core
+make -C /foo/triops/RIOT_App/RIOT/core/lib
+make -C /foo/triops/RIOT_App/RIOT/cpu/fe310
+make -C /foo/triops/RIOT_App/RIOT/cpu/fe310/periph
+make -C /foo/triops/RIOT_App/RIOT/cpu/fe310/vendor
+make -C /foo/triops/RIOT_App/RIOT/cpu/riscv_common
+make -C /foo/triops/RIOT_App/RIOT/cpu/riscv_common/periph
+make -C /foo/triops/RIOT_App/RIOT/drivers
+make -C /foo/triops/RIOT_App/RIOT/drivers/periph_common
+make -C /foo/triops/RIOT_App/RIOT/sys
+make -C /foo/triops/RIOT_App/RIOT/sys/auto_init
+make -C /foo/triops/RIOT_App/RIOT/sys/div
+make -C /foo/triops/RIOT_App/RIOT/sys/isrpipe
+make -C /foo/triops/RIOT_App/RIOT/sys/libc
+make -C /foo/triops/RIOT_App/RIOT/sys/malloc_thread_safe
+make -C /foo/triops/RIOT_App/RIOT/sys/newlib_syscalls_default
+make -C /foo/triops/RIOT_App/RIOT/sys/preprocessor
+make -C /foo/triops/RIOT_App/RIOT/sys/ps
+make -C /foo/triops/RIOT_App/RIOT/sys/shell
+make -C /foo/triops/RIOT_App/RIOT/sys/shell/cmds
+make -C /foo/triops/RIOT_App/RIOT/sys/stdio
+make -C /foo/triops/RIOT_App/RIOT/sys/stdio_uart
+make -C /foo/triops/RIOT_App/RIOT/sys/tsrb
+   text    data     bss     dec     hex filename
+   8850    1193    2628   12671    317f /foo/triops/RIOT_App/app/bin/hifive1b/triops_app.elf
+```
+
+4. Run RIOT within TRIOPS. This assumes that you already built TRIOPS using `cargo build`!
+```sh
+make term
+```

RIOT_App/app/Makefile

@@ -0,0 +1,27 @@
+# name of your application
+APPLICATION = triops_app
+
+# If no BOARD is found in the environment, use this default:
+BOARD = hifive1b
+
+# Comment this out to disable code in RIOT that does safety checking
+# which is not needed in a production environment but helps in the
+# development process:
+DEVELHELP ?= 1
+
+# Change this to 0 show compiler invocation lines by default:
+QUIET ?= 1
+
+# Modules to include:
+USEMODULE += shell
+USEMODULE += shell_cmds_default
+USEMODULE += ps
+
+TERMPROG = ../../target/debug/triops
+TERMFLAGS = $(ELFFILE)
+
+PROJECT_BASE ?= $(CURDIR)/../
+# This has to be the absolute path to the RIOT base directory:
+RIOTBASE ?= $(PROJECT_BASE)/RIOT
+
+include $(RIOTBASE)/Makefile.include

RIOT_App/app/main.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+#include "shell.h"
+
+int main(void)
+{
+    puts("Hello TRIOPS!");
+
+    printf("You are running RIOT on a(n) %s (emulated) board.\n", RIOT_BOARD);
+    printf("This board features a(n) %s CPU.\n", RIOT_CPU);
+
+    printf("You are in the RIOT shell now, type 'help' for...help.\n");
+
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(NULL, line_buf, SHELL_DEFAULT_BUFSIZE);
+
+    return 0;
+}