Add CI/CD pipeline and fix semihosting exit

.ci/check-format.sh

@@ -0,0 +1,100 @@
+#!/usr/bin/env bash
+
+# The -e is not set because we want to get all the mismatch format at once
+
+set -u -o pipefail
+
+# In CI environment, require all formatting tools to be present
+# Set CI=true to enforce tool presence (GitHub Actions sets this automatically)
+REQUIRE_TOOLS="${CI:-false}"
+
+C_FORMAT_EXIT=0
+SH_FORMAT_EXIT=0
+
+# On pull requests, check only changed files so pre-existing formatting
+# debt does not block unrelated PRs.  On push (to main) or local runs
+# without GITHUB_BASE_REF, check the full tree.
+if [ -n "${GITHUB_BASE_REF:-}" ]; then
+    echo "PR mode: checking only files changed vs origin/${GITHUB_BASE_REF}"
+    if git fetch --depth=1 origin "${GITHUB_BASE_REF}" 2> /dev/null \
+        && CHANGED=$(git diff --name-only --diff-filter=d "origin/${GITHUB_BASE_REF}"...HEAD 2> /dev/null); then
+        # If formatting config changed, check the full tree against the new rules.
+        if printf '%s\n' "$CHANGED" | grep -qE '^\.(clang-format|editorconfig)$'; then
+            echo "Formatting config changed; checking full tree"
+            CHANGED=$(git ls-files)
+        fi
+    else
+        echo "Warning: cannot compute PR diff, falling back to full-tree check" >&2
+        CHANGED=$(git ls-files)
+    fi
+else
+    CHANGED=$(git ls-files)
+fi
+
+# Filter changed files into language-specific sets
+C_SOURCES=()
+while IFS= read -r file; do
+    [ -n "$file" ] || continue
+    case "$file" in
+        include/*.h | src/*.c | src/*.h | ports/*.c | ports/*.h | \
+            ports/*/*.c | ports/*/*.h | \
+            ports/*/*/*.c | ports/*/*/*.h)
+            C_SOURCES+=("$file")
+            ;;
+    esac
+done <<< "$CHANGED"
+
+if [ ${#C_SOURCES[@]} -gt 0 ]; then
+    if command -v clang-format-20 > /dev/null 2>&1; then
+        echo "Checking C files with clang-format-20..."
+        clang-format-20 -n --Werror "${C_SOURCES[@]}"
+        C_FORMAT_EXIT=$?
+    elif command -v clang-format > /dev/null 2>&1; then
+        echo "Checking C files with clang-format..."
+        clang-format -n --Werror "${C_SOURCES[@]}"
+        C_FORMAT_EXIT=$?
+    else
+        if [ "$REQUIRE_TOOLS" = "true" ]; then
+            echo "ERROR: clang-format not found (required in CI)" >&2
+            C_FORMAT_EXIT=1
+        else
+            echo "Skipping C format check: clang-format not found" >&2
+        fi
+    fi
+fi
+
+SH_SOURCES=()
+while IFS= read -r file; do
+    [ -n "$file" ] || continue
+    case "$file" in
+        *.sh | .ci/*.sh | scripts/*.sh)
+            SH_SOURCES+=("$file")
+            ;;
+    esac
+done <<< "$CHANGED"
+
+if [ ${#SH_SOURCES[@]} -gt 0 ]; then
+    if command -v shfmt > /dev/null 2>&1; then
+        echo "Checking shell scripts..."
+        MISMATCHED_SH=$(shfmt -l "${SH_SOURCES[@]}")
+        if [ -n "$MISMATCHED_SH" ]; then
+            echo "The following shell scripts are not formatted correctly:"
+            printf '%s\n' "$MISMATCHED_SH"
+            shfmt -d "${SH_SOURCES[@]}"
+            SH_FORMAT_EXIT=1
+        fi
+    else
+        if [ "$REQUIRE_TOOLS" = "true" ]; then
+            echo "ERROR: shfmt not found (required in CI)" >&2
+            SH_FORMAT_EXIT=1
+        else
+            echo "Skipping shell script format check: shfmt not found" >&2
+        fi
+    fi
+fi
+
+# Use logical OR to avoid exit code overflow (codes are mod 256)
+if [ $C_FORMAT_EXIT -ne 0 ] || [ $SH_FORMAT_EXIT -ne 0 ]; then
+    exit 1
+fi
+exit 0

.ci/check-newline.sh

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+
+set -e -u -o pipefail
+
+ret=0
+show=0
+
+# Check all tracked text files for trailing newlines
+# Excludes: externals/ and cloned RTOS trees (third-party code with own style)
+# Reference: https://medium.com/@alexey.inkin/how-to-force-newline-at-end-of-files-and-why-you-should-do-it-fdf76d1d090e
+while IFS= read -rd '' f; do
+    # Skip third-party directories
+    case "$f" in
+        externals/* | threadx/* | freertos-kernel/* | tools/kconfig/*) continue ;;
+    esac
+
+    # Skip empty files
+    [ -s "$f" ] || continue
+
+    if file --mime-encoding "$f" | grep -qv binary; then
+        tail -c1 < "$f" | read -r _ || show=1
+        if [ $show -eq 1 ]; then
+            echo "Warning: No newline at end of file $f"
+            ret=1
+            show=0
+        fi
+    fi
+done < <(git ls-files -z)
+
+exit $ret

.ci/common.sh

@@ -0,0 +1,67 @@
+# Bash strict mode (enabled only when executed directly, not sourced)
+if ! (return 0 2> /dev/null); then
+    set -euo pipefail
+fi
+
+# Expect host is Linux/x86_64, Linux/aarch64, macOS/arm64
+
+MACHINE_TYPE=$(uname -m)
+OS_TYPE=$(uname -s)
+
+check_platform()
+{
+    case "${MACHINE_TYPE}/${OS_TYPE}" in
+        x86_64/Linux | aarch64/Linux | arm64/Darwin) ;;
+
+        *)
+            echo "Unsupported platform: ${MACHINE_TYPE}/${OS_TYPE}"
+            exit 1
+            ;;
+    esac
+}
+
+if [ "${OS_TYPE}" = "Linux" ]; then
+    PARALLEL=-j$(nproc)
+else
+    PARALLEL=-j$(sysctl -n hw.logicalcpu)
+fi
+
+# Color output helpers
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+NC='\033[0m' # No Color
+
+print_success()
+{
+    echo -e "${GREEN}[SUCCESS]${NC} $1"
+}
+
+print_error()
+{
+    echo -e "${RED}[ERROR]${NC} $1" >&2
+}
+
+print_warning()
+{
+    echo -e "${YELLOW}[WARNING]${NC} $1"
+}
+
+# Cleanup function registry
+CLEANUP_FUNCS=()
+
+register_cleanup()
+{
+    CLEANUP_FUNCS+=("$1")
+}
+
+cleanup()
+{
+    local func
+    for func in "${CLEANUP_FUNCS[@]-}"; do
+        [ -n "${func}" ] || continue
+        eval "${func}" || true
+    done
+}
+
+trap cleanup EXIT

.ci/install-deps.sh

@@ -0,0 +1,83 @@
+#!/usr/bin/env bash
+
+# Install build dependencies for CI
+# Usage: .ci/install-deps.sh [posix|cortex-m|format|analysis]
+
+set -euo pipefail
+
+source "$(dirname "$0")/common.sh"
+
+MODE="${1:-posix}"
+
+# Setup LLVM 20 APT repository (shared by format and analysis modes)
+setup_llvm_repo()
+{
+    LLVM_KEYRING=/usr/share/keyrings/llvm-archive-keyring.gpg
+    LLVM_KEY_FP="6084F3CF814B57C1CF12EFD515CF4D18AF4F7421"
+    TMPKEY=$(mktemp)
+    curl -fsSL https://apt.llvm.org/llvm-snapshot.gpg.key -o "$TMPKEY"
+    ACTUAL_FP=$(gpg --with-fingerprint --with-colons "$TMPKEY" 2> /dev/null | grep fpr | head -1 | cut -d: -f10)
+    if [ "$ACTUAL_FP" != "$LLVM_KEY_FP" ]; then
+        print_error "LLVM key fingerprint mismatch!"
+        print_error "Expected: $LLVM_KEY_FP"
+        print_error "Got: $ACTUAL_FP"
+        rm -f "$TMPKEY"
+        exit 1
+    fi
+    sudo gpg --dearmor -o "$LLVM_KEYRING" < "$TMPKEY"
+    rm -f "$TMPKEY"
+
+    CODENAME=$(lsb_release -cs)
+    echo "deb [signed-by=${LLVM_KEYRING}] https://apt.llvm.org/${CODENAME}/ llvm-toolchain-${CODENAME}-20 main" | sudo tee /etc/apt/sources.list.d/llvm-20.list
+    sudo apt-get update -q=2
+}
+
+case "$MODE" in
+    posix)
+        # POSIX host builds only need a C compiler (pre-installed) and python3.
+        if [ "$OS_TYPE" = "Linux" ]; then
+            sudo apt-get update -q=2
+            sudo apt-get install -y -q=2 --no-install-recommends python3
+        else
+            brew install python3
+        fi
+        ;;
+    cortex-m)
+        # Cortex-M QEMU builds: cross-compiler + emulator.
+        if [ "$OS_TYPE" != "Linux" ]; then
+            print_error "Cortex-M CI only supported on Linux"
+            exit 1
+        fi
+        sudo apt-get update -q=2
+        sudo apt-get install -y -q=2 --no-install-recommends \
+            gcc-arm-none-eabi libnewlib-arm-none-eabi \
+            qemu-system-arm python3
+        ;;
+    format)
+        if [ "$OS_TYPE" != "Linux" ]; then
+            print_error "Formatting tools only supported on Linux"
+            exit 1
+        fi
+        sudo apt-get update -q=2
+        sudo apt-get install -y -q=2 --no-install-recommends shfmt gnupg ca-certificates lsb-release
+        setup_llvm_repo
+        sudo apt-get install -y -q=2 --no-install-recommends clang-format-20
+        ;;
+    analysis)
+        if [ "$OS_TYPE" != "Linux" ]; then
+            print_error "Static analysis only supported on Linux"
+            exit 1
+        fi
+        sudo apt-get update -q=2
+        sudo apt-get install -y -q=2 --no-install-recommends gnupg ca-certificates lsb-release python3
+        setup_llvm_repo
+        sudo apt-get install -y -q=2 --no-install-recommends clang-20 clang-tools-20
+        ;;
+    *)
+        print_error "Unknown mode: $MODE"
+        echo "Usage: $0 [posix|cortex-m|format|analysis]"
+        exit 1
+        ;;
+esac
+
+print_success "Dependencies installed for mode: $MODE"

.editorconfig

@@ -0,0 +1,14 @@
+# Top-level EditorConfig file
+root = true
+
+# Shell script-specific settings
+[*.sh]
+indent_style = space
+indent_size = 4
+end_of_line = lf
+trim_trailing_whitespace = true
+insert_final_newline = true
+function_next_line = true
+switch_case_indent = true
+space_redirects = true
+binary_next_line = true