Install Rust in docker image, add Rust library and build rules (#41)

* Install Rust in docker image * Also install thumbv7em-none-eabi target * Install Rust in docker image * Also install thumbv7em-none-eabi target * Add Rust example * Link to the Rust example * Call function from the Rust lib * Move PROJECT_DIR to the 'paths' section * Fix target_f1 build * Link to the Rust library in target_f1 * Generate cbindgen bindings * Add forgotten dependency line * Use panic=abort instead of eh_personality lang item * Install Rust in docker image * Also install thumbv7em-none-eabi target * Add Rust example * Link to the Rust example * Call function from the Rust lib * Move PROJECT_DIR to the 'paths' section * Link to the Rust library in target_f1 * Generate cbindgen bindings * Add forgotten dependency line * Use panic=abort instead of eh_personality lang item * add rust call test Co-authored-by: aanper <mail@s3f.ru>
2020-08-26 13:08:20 +03:00 · 2020-08-26 13:08:20 +03:00 · 1bec8dd23a
commit 1bec8dd23a
parent 046a20fa0e
11 changed files with 478 additions and 11 deletions
--- a/6
+++ b/6
@ -2,9 +2,13 @@ FROM ubuntu:18.04

 RUN apt-get update && apt-get install -y --no-install-recommends \
 make gcc-arm-none-eabi binutils-arm-none-eabi libnewlib-arm-none-eabi \
-autoconf automake libtool curl wget g++ unzip && \
+autoconf automake libtool curl wget g++ unzip build-essential curl && \
 apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*

 RUN apt-get update && apt-get install -y --no-install-recommends \
 python python-pip libstdc++-arm-none-eabi-newlib && \
 apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
+
+RUN curl https://sh.rustup.rs -sSf | sh -s -- -y --profile=minimal --target thumbv7em-none-eabi thumbv7em-none-eabihf
+ENV PATH="/root/.cargo/bin:${PATH}"
+ENV USER=root
--- a/applications/tests/test_index.c
+++ b/applications/tests/test_index.c
@ -2,6 +2,8 @@
 #include "flipper.h"
 #include "debug.h"

+#include "flipper-core.h"
+
 bool furi_ac_create_kill(FILE* debug_uart);
 bool furi_ac_switch_exit(FILE* debug_uart);

@ -56,5 +58,11 @@ void flipper_test_app(void* p) {
        fprintf(debug_uart, "[TEST] furi_mute_algorithm FAILED\n");
    }

+    if(add(1, 2) == 3) {
+        fprintf(debug_uart, "[TEST] Rust add PASSED\n");
+    } else {
+        fprintf(debug_uart, "[TEST] Rust add FAILED\n");
+    }
+
    furiac_exit(NULL);
 }
--- a/core-rs/.gitignore
+++ b/core-rs/.gitignore
@ -0,0 +1,3 @@
+/bindings
+/target
+/.idea
--- a/core-rs/Cargo.lock
+++ b/core-rs/Cargo.lock
@ -0,0 +1,341 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "ansi_term"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee49baf6cb617b853aa8d93bf420db2383fab46d314482ca2803b40d5fde979b"
+dependencies = [
+ "winapi",
+]
+
+[[package]]
+name = "atty"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
+dependencies = [
+ "hermit-abi",
+ "libc",
+ "winapi",
+]
+
+[[package]]
+name = "bitflags"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
+
+[[package]]
+name = "cbindgen"
+version = "0.14.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e783d38a7700989e0209d0b0ed224c34ade92d3603da0cf15dc502ebada685a6"
+dependencies = [
+ "clap",
+ "heck",
+ "log",
+ "proc-macro2",
+ "quote",
+ "serde",
+ "serde_json",
+ "syn",
+ "tempfile",
+ "toml",
+]
+
+[[package]]
+name = "cfg-if"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
+
+[[package]]
+name = "clap"
+version = "2.33.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "37e58ac78573c40708d45522f0d80fa2f01cc4f9b4e2bf749807255454312002"
+dependencies = [
+ "ansi_term",
+ "atty",
+ "bitflags",
+ "strsim",
+ "textwrap",
+ "unicode-width",
+ "vec_map",
+]
+
+[[package]]
+name = "flipper-core"
+version = "0.1.0"
+dependencies = [
+ "cbindgen",
+]
+
+[[package]]
+name = "getrandom"
+version = "0.1.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7abc8dd8451921606d809ba32e95b6111925cd2906060d2dcc29c070220503eb"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi",
+]
+
+[[package]]
+name = "heck"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "20564e78d53d2bb135c343b3f47714a56af2061f1c928fdb541dc7b9fdd94205"
+dependencies = [
+ "unicode-segmentation",
+]
+
+[[package]]
+name = "hermit-abi"
+version = "0.1.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3deed196b6e7f9e44a2ae8d94225d80302d81208b1bb673fd21fe634645c85a9"
+dependencies = [
+ "libc",
+]
+
+[[package]]
+name = "itoa"
+version = "0.4.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dc6f3ad7b9d11a0c00842ff8de1b60ee58661048eb8049ed33c73594f359d7e6"
+
+[[package]]
+name = "libc"
+version = "0.2.76"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "755456fae044e6fa1ebbbd1b3e902ae19e73097ed4ed87bb79934a867c007bc3"
+
+[[package]]
+name = "log"
+version = "0.4.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4fabed175da42fed1fa0746b0ea71f412aa9d35e76e95e59b192c64b9dc2bf8b"
+dependencies = [
+ "cfg-if",
+]
+
+[[package]]
+name = "ppv-lite86"
+version = "0.2.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c36fa947111f5c62a733b652544dd0016a43ce89619538a8ef92724a6f501a20"
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "04f5f085b5d71e2188cb8271e5da0161ad52c3f227a661a3c135fdf28e258b12"
+dependencies = [
+ "unicode-xid",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "aa563d17ecb180e500da1cfd2b028310ac758de548efdd203e18f283af693f37"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "rand"
+version = "0.7.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a6b1679d49b24bbfe0c803429aa1874472f50d9b363131f0e89fc356b544d03"
+dependencies = [
+ "getrandom",
+ "libc",
+ "rand_chacha",
+ "rand_core",
+ "rand_hc",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f4c8ed856279c9737206bf725bf36935d8666ead7aa69b52be55af369d193402"
+dependencies = [
+ "ppv-lite86",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "90bde5296fc891b0cef12a6d03ddccc162ce7b2aff54160af9338f8d40df6d19"
+dependencies = [
+ "getrandom",
+]
+
+[[package]]
+name = "rand_hc"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ca3129af7b92a17112d59ad498c6f81eaf463253766b90396d39ea7a39d6613c"
+dependencies = [
+ "rand_core",
+]
+
+[[package]]
+name = "redox_syscall"
+version = "0.1.57"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "41cc0f7e4d5d4544e8861606a285bb08d3e70712ccc7d2b84d7c0ccfaf4b05ce"
+
+[[package]]
+name = "remove_dir_all"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3acd125665422973a33ac9d3dd2df85edad0f4ae9b00dafb1a05e43a9f5ef8e7"
+dependencies = [
+ "winapi",
+]
+
+[[package]]
+name = "ryu"
+version = "1.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "71d301d4193d031abdd79ff7e3dd721168a9572ef3fe51a1517aba235bd8f86e"
+
+[[package]]
+name = "serde"
+version = "1.0.115"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e54c9a88f2da7238af84b5101443f0c0d0a3bbdc455e34a5c9497b1903ed55d5"
+dependencies = [
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.115"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "609feed1d0a73cc36a0182a840a9b37b4a82f0b1150369f0536a9e3f2a31dc48"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "serde_json"
+version = "1.0.57"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "164eacbdb13512ec2745fb09d51fd5b22b0d65ed294a1dcf7285a360c80a675c"
+dependencies = [
+ "itoa",
+ "ryu",
+ "serde",
+]
+
+[[package]]
+name = "strsim"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
+
+[[package]]
+name = "syn"
+version = "1.0.39"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "891d8d6567fe7c7f8835a3a98af4208f3846fba258c1bc3c31d6e506239f11f9"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-xid",
+]
+
+[[package]]
+name = "tempfile"
+version = "3.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a6e24d9338a0a5be79593e2fa15a648add6138caa803e2d5bc782c371732ca9"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "rand",
+ "redox_syscall",
+ "remove_dir_all",
+ "winapi",
+]
+
+[[package]]
+name = "textwrap"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d326610f408c7a4eb6f51c37c330e496b08506c9457c9d34287ecc38809fb060"
+dependencies = [
+ "unicode-width",
+]
+
+[[package]]
+name = "toml"
+version = "0.5.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ffc92d160b1eef40665be3a05630d003936a3bc7da7421277846c2613e92c71a"
+dependencies = [
+ "serde",
+]
+
+[[package]]
+name = "unicode-segmentation"
+version = "1.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e83e153d1053cbb5a118eeff7fd5be06ed99153f00dbcd8ae310c5fb2b22edc0"
+
+[[package]]
+name = "unicode-width"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9337591893a19b88d8d87f2cec1e73fad5cdfd10e5a6f349f498ad6ea2ffb1e3"
+
+[[package]]
+name = "unicode-xid"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f7fe0bb3479651439c9112f72b6c505038574c9fbb575ed1bf3b797fa39dd564"
+
+[[package]]
+name = "vec_map"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f1bddf1187be692e79c5ffeab891132dfb0f236ed36a43c7ed39f1165ee20191"
+
+[[package]]
+name = "wasi"
+version = "0.9.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
+
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
--- a/core-rs/Cargo.toml
+++ b/core-rs/Cargo.toml
@ -0,0 +1,20 @@
+[package]
+name = "flipper-core"
+version = "0.1.0"
+authors = ["Vadim Kaushan <admin@disasm.info>"]
+edition = "2018"
+
+[lib]
+crate-type = ["staticlib"]
+
+[build-dependencies]
+cbindgen = "0.14"
+
+[profile.release]
+codegen-units = 1 # better optimizations
+debug = true # symbols are nice and they don't increase the size on Flash
+lto = true # better optimizations
+panic = "abort"
+
+[profile.dev]
+panic = "abort"
--- a/core-rs/build.rs
+++ b/core-rs/build.rs
@ -0,0 +1,13 @@
+use std::env;
+use std::path::Path;
+
+fn main() {
+    let crate_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
+    let pkg_name = env::var("CARGO_PKG_NAME").unwrap();
+
+    cbindgen::generate(&crate_dir)
+        .expect("Unable to generate cbindgen bindings")
+        .write_to_file(
+            Path::new(&crate_dir).join("bindings").join(format!("{}.h", pkg_name))
+        );
+}
--- a/core-rs/cbindgen.toml
+++ b/core-rs/cbindgen.toml
@ -0,0 +1,4 @@
+language = "C"
+
+[export]
+item_types = ["functions"]
--- a/core-rs/src/lib.rs
+++ b/core-rs/src/lib.rs
@ -0,0 +1,16 @@
+#![no_std]
+
+#[no_mangle]
+pub extern "C" fn add(a: u32, b: u32) -> u32 {
+    a + b
+}
+
+
+mod aux {
+    use core::panic::PanicInfo;
+
+    #[panic_handler]
+    fn panic(_info: &PanicInfo) -> ! {
+        loop { continue }
+    }
+}
--- a/target_f1/Makefile
+++ b/target_f1/Makefile
@ -28,6 +28,7 @@ OPT = -Og
 #######################################
 # paths
 #######################################
+PROJECT_DIR = $(shell dirname $(realpath $(firstword $(MAKEFILE_LIST))))
 # Build path
 BUILD_DIR = build

@ -134,6 +135,10 @@ endif

 # Add C_SOURCES +=, C_DEFS += or CPP_SOURCES += here

+C_SOURCES += ../applications/tests/furiac_test.c
+C_SOURCES += ../applications/tests/furi_record_test.c
+C_SOURCES += ../applications/tests/test_index.c
+
 #######################################
 # binaries
 #######################################
@ -155,7 +160,26 @@ SZ = $(PREFIX)size
 endif
 HEX = $(CP) -O ihex
 BIN = $(CP) -O binary -S
- 
+
+
+#######################################
+# Rust library
+#######################################
+
+RUST_LIB_SRC = $(realpath $(PROJECT_DIR)/../core-rs)
+RUST_LIB_NAME = flipper_core
+RUST_LIB_TARGET = thumbv7em-none-eabihf
+RUST_LIB_FLAGS = --target=$(RUST_LIB_TARGET)
+
+ifeq ($(DEBUG), 1)
+    RUST_LIB_PATH = $(RUST_LIB_SRC)/target/$(RUST_LIB_TARGET)/debug
+else
+	RUST_LIB_FLAGS += --release
+    RUST_LIB_PATH = $(RUST_LIB_SRC)/target/$(RUST_LIB_TARGET)/release
+endif
+
+RUST_LIB_CMD = cd $(RUST_LIB_SRC) && cargo build $(RUST_LIB_FLAGS)
+
 #######################################
 # CFLAGS
 #######################################
@ -193,7 +217,8 @@ C_INCLUDES =  \
 -IDrivers/CMSIS/Device/ST/STM32L4xx/Include \
 -IDrivers/CMSIS/Include \
 -IMiddlewares/ST/STM32_USB_Device_Library/Core/Inc \
-IMiddlewares/ST/STM32_USB_Device_Library/Class/CDC/Inc
+-IMiddlewares/ST/STM32_USB_Device_Library/Class/CDC/Inc \
+-I../core-rs/bindings


 # compile gcc flags
@ -218,8 +243,8 @@ CPPFLAGS = -fno-threadsafe-statics
 LDSCRIPT = STM32L476RGTx_FLASH.ld

 # libraries
-LIBS = -lc -lm -lnosys 
-LIBDIR = 
+LIBS = -lc -lm -lnosys -l$(RUST_LIB_NAME)
+LIBDIR = -L$(RUST_LIB_PATH)
 LDFLAGS = $(MCU) -specs=nano.specs -specs=nosys.specs -T$(LDSCRIPT) $(LIBDIR) $(LIBS) -Wl,-Map=$(BUILD_DIR)/$(TARGET).map,--cref -Wl,--gc-sections

 # default action: build all
@ -258,7 +283,10 @@ $(BUILD_DIR)/%.o: %.s Makefile | $(BUILD_DIR)
 $(BUILD_DIR)/%.pb.c $(BUILD_DIR)/%.pb.h: ../flipper_proto/%.proto
 	$(PROTOC) $(PROTOC_OPTS) --nanopb_out=$(BUILD_DIR) $<

-$(BUILD_DIR)/$(TARGET).elf: $(OBJECTS) Makefile
+$(RUST_LIB_PATH)/lib$(RUST_LIB_NAME).a:
+	$(RUST_LIB_CMD)
+
+$(BUILD_DIR)/$(TARGET).elf: $(RUST_LIB_PATH)/lib$(RUST_LIB_NAME).a $(OBJECTS) Makefile
 	$(CPP) $(OBJECTS) $(LDFLAGS) -o $@
 	$(SZ) $@

@ -276,10 +304,12 @@ $(BUILD_DIR):
 #######################################
 clean:
 	-rm -fR $(BUILD_DIR)
+	cd $(RUST_LIB_SRC) && cargo clean
  
 #######################################
 # dependencies
 #######################################
 -include $(wildcard $(BUILD_DIR)/*.d)
+-include $(wildcard $(RUST_LIB_PATH)/*.d)

 # *** EOF ***
--- a/target_lo/Makefile
+++ b/target_lo/Makefile
@ -13,6 +13,7 @@ OPT = -Og
 #######################################
 # paths
 #######################################
+PROJECT_DIR = $(shell dirname $(realpath $(firstword $(MAKEFILE_LIST))))
 # Build path
 BUILD_DIR = build

@ -70,7 +71,26 @@ CP = objcopy
 SZ = size
 HEX = $(CP) -O ihex
 BIN = $(CP) -O binary -S
- 
+
+
+#######################################
+# Rust library
+#######################################
+
+RUST_LIB_SRC = $(realpath $(PROJECT_DIR)/../core-rs)
+RUST_LIB_NAME = flipper_core
+RUST_LIB_TARGET = x86_64-unknown-linux-gnu
+RUST_LIB_FLAGS = --target=$(RUST_LIB_TARGET)
+
+ifeq ($(DEBUG), 1)
+    RUST_LIB_PATH = $(RUST_LIB_SRC)/target/$(RUST_LIB_TARGET)/debug
+else
+	RUST_LIB_FLAGS += --release
+    RUST_LIB_PATH = $(RUST_LIB_SRC)/target/$(RUST_LIB_TARGET)/release
+endif
+
+RUST_LIB_CMD = cd $(RUST_LIB_SRC) && cargo build $(RUST_LIB_FLAGS)
+
 #######################################
 # CFLAGS
 #######################################
@ -80,7 +100,8 @@ BIN = $(CP) -O binary -S
 C_INCLUDES =  \
 -IInc \
 -I../applications \
-I../core
+-I../core \
+-I../core-rs/bindings

 # compile gcc flags
 CFLAGS = $(C_DEFS) $(C_INCLUDES) $(OPT) -Wall -fdata-sections -ffunction-sections -pthread
@ -100,8 +121,8 @@ CPPFLAGS = -fno-threadsafe-statics
 #######################################

 # libraries
-LIBS = -lc -lm
-LIBDIR = 
+LIBS = -lc -lm -l$(RUST_LIB_NAME)
+LIBDIR = -L$(RUST_LIB_PATH)
 LDFLAGS = $(LIBDIR) $(LIBS) -Wl,-Map=$(BUILD_DIR)/$(TARGET).map,--cref -Wl,--gc-sections -pthread

 # default action: build all
@ -132,7 +153,10 @@ $(BUILD_DIR)/%.o: %.c Makefile | $(BUILD_DIR)
 $(BUILD_DIR)/%.o: %.cpp Makefile | $(BUILD_DIR)
 	$(CPP) -c $(CFLAGS) $(CPPFLAGS) -Wa,-a,-ad,-alms=$(BUILD_DIR)/$(notdir $(<:.c=.lst)) $< -o $@

-$(BUILD_DIR)/$(TARGET): $(OBJECTS) Makefile
+$(RUST_LIB_PATH)/lib$(RUST_LIB_NAME).a:
+	$(RUST_LIB_CMD)
+
+$(BUILD_DIR)/$(TARGET): $(RUST_LIB_PATH)/lib$(RUST_LIB_NAME).a $(OBJECTS) Makefile
 	$(CPP) $(OBJECTS) $(LDFLAGS) -o $@
 	$(SZ) $@
 	
@ -144,10 +168,12 @@ $(BUILD_DIR):
 #######################################
 clean:
 	-rm -fR $(BUILD_DIR)
+	cd $(RUST_LIB_SRC) && cargo clean

 #######################################
 # dependencies
 #######################################
 -include $(wildcard $(BUILD_DIR)/*.d)
+-include $(wildcard $(RUST_LIB_PATH)/*.d)

 # *** EOF ***
--- a/target_lo/Src/main.c
+++ b/target_lo/Src/main.c
@ -5,8 +5,10 @@ Local fw build entry point.
 */

 void app();
+unsigned int add(unsigned int a, unsigned int b);

 int main() {
+    add(2, 2);
    app();

    return 0;