From 06fd67c1d2104cbe09cc9811cd5d160e808f7698 Mon Sep 17 00:00:00 2001
From: pyao12 <patrick25yao@outlook.com>
Date: Sat, 9 May 2026 20:07:36 +0800
Subject: [PATCH] Hello UEFI!

---
 .gitignore |  3 +++
 Makefile   | 18 ++++++++++++++++++
 boot.c     | 22 ++++++++++++++++++++++
 3 files changed, 43 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 Makefile
 create mode 100644 boot.c

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..5620f0e
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+build/
+vdir/
+.vscode/
\ No newline at end of file
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..b9113ba
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,18 @@
+MINGW_GCC = x86_64-w64-mingw32-gcc
+QEMU = qemu-system-x86_64
+MINGW_GCC_FLAGS = -Wall -Wextra -e efi_main -nostdinc -nostdlib  -fno-builtin -Wl,--subsystem,10
+
+all: 
+	mkdir -p build
+	x86_64-w64-mingw32-gcc $(MINGW_GCC_FLAGS) -o build/BOOTX64.EFI boot.c
+
+vdir: all
+	mkdir -p vdir
+	mkdir -p vdir/EFI/BOOT
+	cp build/BOOTX64.EFI vdir/EFI/BOOT
+
+run: vdir
+	$(QEMU) -bios /usr/share/ovmf/OVMF.fd -net none -drive file=fat:rw:vdir,index=0,format=vvfat -serial stdio
+
+clean:
+	rm -rf build vdir
\ No newline at end of file
diff --git a/boot.c b/boot.c
new file mode 100644
index 0000000..3b253fb
--- /dev/null
+++ b/boot.c
@@ -0,0 +1,22 @@
+#define ull unsigned long long
+
+struct EFI_SYSTEM_TABLE {
+    char _buf[60];
+    struct EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL {
+        ull _buf;
+        ull (*OutputString)(
+            struct EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL *This,
+            unsigned short *String);
+        ull _buf2[4];
+        ull (*ClearScreen)(
+             struct EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL *This);
+    } *ConOut;
+};
+  
+void efi_main(void *ImageHandle __attribute__ ((unused)), struct EFI_SYSTEM_TABLE *SystemTable)
+{
+    SystemTable->ConOut->ClearScreen(SystemTable->ConOut);
+    SystemTable->ConOut->OutputString(SystemTable->ConOut, L"Hello UEFI!\n");
+    while (1);
+}
+