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rauhulrauhul
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Modernize rpi-4 & 5 builds
Updates the rpi-5-blink example to link using SwiftPM and use a toolset.json.
1 parent 0531e4a commit 745fcc7

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17 files changed

+207
-119
lines changed

17 files changed

+207
-119
lines changed

‎Tools/Toolsets/rpi-5-elf.json‎

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{
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"schemaVersion": "1.0",
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"swiftCompiler": {
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"extraCLIOptions": [
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"-Xfrontend", "-disable-stack-protector",
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"-Xfrontend", "-function-sections",
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"-enable-experimental-feature", "Embedded",
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"-Xfrontend", "-mergeable-symbols",
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"-Xclang-linker", "-fuse-ld=lld",
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"-Xclang-linker", "-nostdlib"
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]
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},
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"linker": {
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"extraCLIOptions": [
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"-T", "Sources/Support/linkerscript.ld",
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"--unresolved-symbols=ignore-in-object-files"
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]
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}
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}

‎rpi-4b-blink/Makefile‎

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@@ -1,28 +1,47 @@
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SWIFT_EXEC ?= $(shell if [ "$(shell uname)" = "Darwin" ]; then xcrun -f swift; else which swift; fi)
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CLANG ?= $(shell if [ "$(shell uname)" = "Darwin" ]; then xcrun -f clang; else which clang; fi)
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LLVM_OBJCOPY ?= $(shell if [ "$(shell uname)" = "Darwin" ]; then xcrun -f llvm-objcopy; else which llvm-objcopy; fi)
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##===----------------------------------------------------------------------===##
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##
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## This source file is part of the Swift open source project
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##
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## Copyright (c) 2025 Apple Inc. and the Swift project authors.
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## Licensed under Apache License v2.0 with Runtime Library Exception
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##
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## See https://swift.org/LICENSE.txt for license information
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##
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##===----------------------------------------------------------------------===##
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BUILDROOT := $(shell $(SWIFT_EXEC) build --configuration release --triple aarch64-none-none-elf -Xswiftc -Xfrontend -Xswiftc -disable-stack-protector --show-bin-path)
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# Paths
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REPOROOT := $(shell git rev-parse --show-toplevel)
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TOOLSROOT := $(REPOROOT)/Tools
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TOOLSET := $(TOOLSROOT)/Toolsets/rpi-5-elf.json
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LLVM_OBJCOPY := llvm-objcopy
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SWIFT_BUILD := swift build
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7-
.PHONY: all clean
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# Flags
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ARCH := aarch64
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TARGET := $(ARCH)-none-none-elf
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SWIFT_BUILD_ARGS := \
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--configuration release \
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--triple $(TARGET) \
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--toolset $(TOOLSET) \
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--disable-local-rpath
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BUILDROOT := $(shell $(SWIFT_BUILD) $(SWIFT_BUILD_ARGS) --show-bin-path)
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9-
all: kernel8.img
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.PHONY: build
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build:
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@echo "building..."
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$(SWIFT_BUILD) \
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$(SWIFT_BUILD_ARGS) \
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--verbose
1035

11-
kernel8.img: kernel8.elf
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@echo "💾 Converting to binary kernel image with llvm-objcopy..."
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$(LLVM_OBJCOPY) -O binary kernel8.elf kernel8.img
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@echo ""
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@echo "🥳 Done! kernel8.img was saved to this directory."
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@echo "extracting binary..."
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$(LLVM_OBJCOPY) \
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-O binary \
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"$(BUILDROOT)/Application" \
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"$(BUILDROOT)/Application.bin" \
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17-
kernel8.elf: $(BUILDROOT)/libMainApp.a $(BUILDROOT)/Support.build/boot.S.o link.ld
18-
@echo "🔗 Linking with clang..."
19-
$(CLANG) --target=aarch64-elf -o kernel8.elf $< $^ -fuse-ld=lld -nostdlib -Wl,--unresolved-symbols=ignore-in-object-files -Wl,-T ./link.ld
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@echo ""
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$(BUILDROOT)/libMainApp.a $(BUILDROOT)/Support.build/boot.S.o:
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@echo "🛠️ Building with Swift Package Manager..."
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$(SWIFT_EXEC) build --configuration release --triple aarch64-none-none-elf -Xswiftc -Xfrontend -Xswiftc -disable-stack-protector
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@echo ""
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.PHONY: clean
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clean:
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rm -rf kernel8.elf kernel8.img .build
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@echo "cleaning..."
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@swift package clean
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@rm -rf .build

‎rpi-4b-blink/Package.resolved‎

Lines changed: 3 additions & 3 deletions
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‎rpi-4b-blink/Package.swift‎

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@@ -3,33 +3,19 @@
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import PackageDescription
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55
let package = Package(
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name: "RPi4B-Blink",
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platforms: [
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.macOS(.v14)
9-
],
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name: "rpi-4b-blink",
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products: [
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.library(
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name: "MainApp",
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type: .static,
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targets: ["MainApp"])
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.executable(name: "Application", targets: ["Application"])
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],
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dependencies: [
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.package(
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url: "https://github.com/apple/swift-mmio.git",
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branch: "swift-embedded-examples")
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.package(url: "https://github.com/apple/swift-mmio.git", branch: "main")
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],
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targets: [
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.target(
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name: "MainApp",
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.executableTarget(
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name: "Application",
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dependencies: [
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.product(name: "MMIO", package: "swift-mmio")
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],
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swiftSettings: [
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.enableExperimentalFeature("Embedded"),
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.unsafeFlags(["-Xfrontend", "-function-sections"]),
30-
]
31-
),
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.product(name: "MMIO", package: "swift-mmio"),
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"Support",
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]),
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.target(name: "Support"),
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34-
]
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)
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])

‎rpi-4b-blink/README.md‎

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66

77
- A Raspberry Pi 4B board
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- An SD Card, with a Raspberry Pi OS installed (this way, we don't need to create the configuration files from scratch). You may backup `kernel8.img` and `config.txt` if you need the Linux install later, since we will change these files.
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- LLVM installed (`brew install llvm`) and added to PATH. This is needed to convert the resulted ELF file to binary image format using `llvm-objcopy`.
109

1110
## How to build and run this example:
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1312
- Make sure you have a recent nightly Swift toolchain that has Embedded Swift support.
1413
- Build the program, then copy the kernel image to the SD card.
1514
``` console
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$ cd rpi-4b-blink
17-
$ export TOOLCHAINS='<toolchain-identifier>' # Your Swift nightly toolchain identifier
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$ make
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$ cp kernel8.img /Volumes/bootfs
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$ cp .build/release/Application.bin /Volumes/bootfs/kernel8.img
2018
```
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- If your original OS is not 64-bit, make sure to set `arm_64bit=1` in `config.txt`.
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- Place the SD card in your Raspberry Pi 4B, and connect it to power.
2321
- After the boot sequence, the green (ACT) led will start blinking in a regular pattern.
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‎rpi-4b-blink/Sources/MainApp/MainApp.swift‎ renamed to ‎rpi-4b-blink/Sources/Application/Application.swift‎

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//
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// This source file is part of the Swift open source project
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//
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// Copyright (c) 2024 Apple Inc. and the Swift project authors.
5+
// Copyright (c) 2025 Apple Inc. and the Swift project authors.
66
// Licensed under Apache License v2.0 with Runtime Library Exception
77
//
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// See https://swift.org/LICENSE.txt for license information
99
//
1010
//===----------------------------------------------------------------------===//
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1212
import MMIO
13+
import Support
1314

1415
@Register(bitWidth: 32)
1516
struct GPSET1 {
@@ -66,17 +67,19 @@ func ledOff() {
6667
}
6768
}
6869

69-
@main
70-
struct Main {
70+
func delay() {
71+
for _ in 1..<100000 { nop() }
72+
}
7173

74+
@main
75+
struct Application {
7276
static func main() {
7377
setLedOutput()
74-
7578
while true {
7679
ledOn()
77-
for _ in 1..<100000 {} // just a delay
80+
delay()
7881
ledOff()
79-
for _ in 1..<100000 {} // just a delay
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delay()
8083
}
8184
}
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}

‎rpi-4b-blink/Sources/Support/include/Support.h‎

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//===----------------------------------------------------------------------===//
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//
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// This source file is part of the Swift open source project
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//
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// Copyright (c) 2025 Apple Inc. and the Swift project authors.
6+
// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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//
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//===----------------------------------------------------------------------===//
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12+
#pragma once
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14+
static inline __attribute((always_inline)) void nop() {
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asm volatile("nop");
16+
}

‎rpi-4b-blink/Sources/Support/include/boot.h‎

Whitespace-only changes.

‎rpi-5-blink/link.ld‎ renamed to ‎rpi-4b-blink/Sources/Support/linkerscript.ld‎

Lines changed: 11 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,7 @@
11
SECTIONS
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{
3-
. = 0x80000; /* Kernel load address for AArch64 */
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/* Kernel load address for AArch64 */
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. = 0x80000;
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.text : { KEEP(*(.text.boot)) *(.text .text.* .gnu.linkonce.t*) }
56
.rodata : { *(.rodata .rodata.* .gnu.linkonce.r*) }
67
PROVIDE(_data = .);
@@ -14,6 +15,13 @@ SECTIONS
1415
}
1516
_end = .;
1617

17-
/DISCARD/ : { *(.comment) *(.gnu*) *(.note*) *(.eh_frame*) }
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/DISCARD/ : {
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*(.comment)
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*(.gnu*)
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*(.note*)
22+
*(.eh_frame*)
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*(.swift_modhash)
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}
1825
}
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__bss_size = (__bss_end - __bss_start)>>3;
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27+
__bss_size = (__bss_end - __bss_start) >> 3;

‎rpi-5-blink/Makefile‎

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@@ -1,28 +1,47 @@
1-
SWIFT_EXEC ?= $(shell if [ "$(shell uname)" = "Darwin" ]; then xcrun -f swift; else which swift; fi)
2-
CLANG ?= $(shell if [ "$(shell uname)" = "Darwin" ]; then xcrun -f clang; else which clang; fi)
3-
LLVM_OBJCOPY ?= $(shell if [ "$(shell uname)" = "Darwin" ]; then xcrun -f llvm-objcopy; else which llvm-objcopy; fi)
1+
##===----------------------------------------------------------------------===##
2+
##
3+
## This source file is part of the Swift open source project
4+
##
5+
## Copyright (c) 2025 Apple Inc. and the Swift project authors.
6+
## Licensed under Apache License v2.0 with Runtime Library Exception
7+
##
8+
## See https://swift.org/LICENSE.txt for license information
9+
##
10+
##===----------------------------------------------------------------------===##
411

5-
BUILDROOT := $(shell $(SWIFT_EXEC) build --configuration release --triple aarch64-none-none-elf -Xswiftc -Xfrontend -Xswiftc -disable-stack-protector --show-bin-path)
12+
# Paths
13+
REPOROOT := $(shell git rev-parse --show-toplevel)
14+
TOOLSROOT := $(REPOROOT)/Tools
15+
TOOLSET := $(TOOLSROOT)/Toolsets/rpi-5-elf.json
16+
LLVM_OBJCOPY := llvm-objcopy
17+
SWIFT_BUILD := swift build
618

7-
.PHONY: all clean
19+
# Flags
20+
ARCH := aarch64
21+
TARGET := $(ARCH)-none-none-elf
22+
SWIFT_BUILD_ARGS := \
23+
--configuration release \
24+
--triple $(TARGET) \
25+
--toolset $(TOOLSET) \
26+
--disable-local-rpath
27+
BUILDROOT := $(shell $(SWIFT_BUILD) $(SWIFT_BUILD_ARGS) --show-bin-path)
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9-
all: kernel8.img
29+
.PHONY: build
30+
build:
31+
@echo "building..."
32+
$(SWIFT_BUILD) \
33+
$(SWIFT_BUILD_ARGS) \
34+
--verbose
1035

11-
kernel8.img: kernel8.elf
12-
@echo "💾 Converting to binary kernel image with llvm-objcopy..."
13-
$(LLVM_OBJCOPY) -O binary kernel8.elf kernel8.img
14-
@echo ""
15-
@echo "🥳 Done! kernel8.img was saved to this directory."
36+
@echo "extracting binary..."
37+
$(LLVM_OBJCOPY) \
38+
-O binary \
39+
"$(BUILDROOT)/Application" \
40+
"$(BUILDROOT)/Application.bin"
1641

17-
kernel8.elf: $(BUILDROOT)/libMainApp.a $(BUILDROOT)/Support.build/boot.S.o link.ld
18-
@echo "🔗 Linking with clang..."
19-
$(CLANG) --target=aarch64-elf -o kernel8.elf $< $^ -fuse-ld=lld -nostdlib -Wl,--unresolved-symbols=ignore-in-object-files -Wl,-T ./link.ld
20-
@echo ""
21-
22-
$(BUILDROOT)/libMainApp.a $(BUILDROOT)/Support.build/boot.S.o:
23-
@echo "🛠️ Building with Swift Package Manager..."
24-
$(SWIFT_EXEC) build --configuration release --triple aarch64-none-none-elf -Xswiftc -Xfrontend -Xswiftc -disable-stack-protector
25-
@echo ""
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43+
.PHONY: clean
2744
clean:
28-
rm -rf kernel8.elf kernel8.img .build
45+
@echo "cleaning..."
46+
@swift package clean
47+
@rm -rf .build

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