Code stub

.gitignore

@@ -1,2 +1,7 @@
-gnu-efi
+*.o
-include
+efi-loader.bin
+loader.bin
+UEFI/gnu-efi
+UEFI/include
+UEFI/BOOTX64.EFI
+UEFI/BOOTIA32.EFI

BIOS/Makefile

@@ -0,0 +1,22 @@
+include ../../Makefile.conf
+
+NAME=loader.bin
+NASM = /usr/bin/nasm
+
+ASM_SOURCES = $(shell find ./ -type f -name '*.asm')
+OBJ = $(ASM_SOURCES:.asm=.o)
+
+prepare:
+	$(info Nothing to prepare)
+
+$(NAME): $(OBJ)
+	cat boot.o second.o > $@
+
+build: $(NAME)
+
+%.o: %.asm
+	$(info Compiling $<)
+	$(NASM) $< -f bin -o $@
+
+clean:
+	rm -f $(OBJ) $(NAME)

BIOS/boot.asm

@@ -0,0 +1,65 @@
+[ORG 0x7C00]
+[BITS 16]
+
+start:
+    jmp	0x0000:Boot
+    nop
+
+times 8-($-$$) db 0
+PrimaryVolumeDescriptor dd 0
+BootFileLocation dd 0
+BootFileLength dd 0
+Checksum dd 0
+Reserved times 40 db 0
+times 90-($-$$) db 0
+
+%include "print.inc"
+
+Boot:
+	cli
+    mov [BOOT_DISK], dl
+	xor ax, ax
+    mov ds, ax
+    mov ss, ax
+    mov sp, 0x9C00
+
+    mov si, ErrorText
+    call Print
+    hlt
+    jmp $
+
+    mov si, BootloaderText
+    call Print
+    call ReadDisk
+    jmp EX_ADDRESS
+    jmp $
+
+ReadDisk:
+    sti
+    mov ah, 0x02
+    mov bx, EX_ADDRESS
+    mov al, 20 ; max 65
+    mov dl, [BOOT_DISK]
+    mov ch, 0x00
+    mov dh, 0x00
+    mov cl, 0x02
+    int 0x13
+    jc DiskError
+    cli
+    ret
+
+DiskError:
+    cli
+    mov si, DiskReadingErrorMessage
+    call Print
+    jmp $
+
+ErrorText db 'BIOS boot not implemented', 0
+BootloaderText db 'Lynx Bootloader', 0
+DiskReadingErrorMessage: db ' Disk Error', 0
+EX_ADDRESS equ 0x8000
+BOOT_DISK: db 0
+
+times 510-($-$$) db 0
+db 0x55
+db 0xAA

BIOS/print.inc

@@ -0,0 +1,9 @@
+Print:
+	lodsb
+	or	al, al
+	jz	PrintDone
+	mov	ah, 0eh
+	int	10h
+	jmp	Print
+PrintDone:
+	ret

BIOS/second.asm

@@ -0,0 +1,9 @@
+; TODO
+init:
+    mov si, LoadingText
+    call Print
+    jmp $
+
+%include "print.inc"
+
+LoadingText db ' Loading...', 0

Makefile

@@ -1,15 +1,14 @@
-GNUEFI_RELEASE_VERSION=3.0.14
+prepare:
+	make -C BIOS prepare
+	make -C UEFI prepare
 
-gnuefi:
+build:
-	wget https://archive.org/download/gnu-efi-$(GNUEFI_RELEASE_VERSION).tar/gnu-efi-$(GNUEFI_RELEASE_VERSION).tar.bz2
+	make -C BIOS build
-	tar -xf gnu-efi-$(GNUEFI_RELEASE_VERSION).tar.bz2
+	make -C UEFI build
-	rm gnu-efi-$(GNUEFI_RELEASE_VERSION).tar.bz2
+	cp BIOS/loader.bin .
-	mv ./gnu-efi-$(GNUEFI_RELEASE_VERSION) ./gnu-efi
+	cp UEFI/efi-loader.bin .
-	mkdir -p include
-	cp -a ./gnu-efi/inc/. ./include
-	make -C gnu-efi
-
-prepare: gnuefi
-	$(info Nothing to prepare)
 
 clean:
+	make -C BIOS clean
+	make -C UEFI clean
+	rm -f loader.bin efi-loader.bin

UEFI/Makefile

@@ -0,0 +1,44 @@
+include ../../Makefile.conf
+
+NAME=efi-loader.bin
+CC = gcc
+LD = ld
+OBJCOPY = objcopy
+
+C_SOURCES = $(shell find ./src -type f -name '*.c')
+OBJ = $(C_SOURCES:.c=.o)
+
+GNUEFI_RELEASE_VERSION=3.0.14
+
+gnuefi:
+	wget https://archive.org/download/gnu-efi-$(GNUEFI_RELEASE_VERSION).tar/gnu-efi-$(GNUEFI_RELEASE_VERSION).tar.bz2
+	tar -xf gnu-efi-$(GNUEFI_RELEASE_VERSION).tar.bz2
+	rm gnu-efi-$(GNUEFI_RELEASE_VERSION).tar.bz2
+	mv ./gnu-efi-$(GNUEFI_RELEASE_VERSION) ./gnu-efi
+	mkdir -p include
+	cp -a ./gnu-efi/inc/. ./include
+	make -C gnu-efi
+
+prepare: gnuefi
+
+build: $(NAME)
+
+$(NAME): BOOTX64
+	dd if=/dev/zero of=$(NAME) bs=512 count=93750
+	mformat -i $(NAME) ::
+	mmd -i $(NAME) ::/EFI
+	mmd -i $(NAME) ::/EFI/BOOT
+	mcopy -i $(NAME) BOOTX64.EFI ::/EFI/BOOT
+
+BOOTX64: $(OBJ)
+	$(LD) -shared -Bsymbolic -Lgnu-efi/x86_64/lib -Lgnu-efi/x86_64/gnuefi -Tgnu-efi/gnuefi/elf_x86_64_efi.lds gnu-efi/x86_64/gnuefi/crt0-efi-x86_64.o $(OBJ) -o tmp.so -lgnuefi -lefi
+	$(OBJCOPY) -j .text -j .sdata -j .data -j .dynamic -j .dynsym  -j .rel -j .rela -j .rel.* -j .rela.* -j .reloc --target efi-app-x86_64 --subsystem=10 tmp.so BOOTX64.EFI
+	rm tmp.so
+
+%.o: %.c
+	$(info Compiling $<)
+	$(CC) -Ignu-efi/inc -Ignu-efi/inc/x86_64 -Ignu-efi/inc/protocol -fpic -ffreestanding -fno-stack-protector -fno-stack-check -fshort-wchar -mno-red-zone -maccumulate-outgoing-args -c $< -o $@
+
+
+clean:
+	rm -f $(NAME) $(OBJ) BOOTX64.EFI

UEFI/src/FileLoader.c

@@ -0,0 +1,8 @@
+#include "FileLoader.h"
+
+// https://wiki.osdev.org/Loading_files_under_UEFI
+
+EFI_FILE *LoadFile(EFI_FILE *Directory, CHAR16 *Path, EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
+{
+    return NULL;
+}

UEFI/src/FileLoader.h

@@ -0,0 +1,5 @@
+#pragma once
+#include <efi.h>
+#include <efilib.h>
+
+EFI_FILE *LoadFile(EFI_FILE *Directory, CHAR16 *Path, EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable);

UEFI/src/Lynx.c

@@ -0,0 +1,23 @@
+#include <efi.h>
+#include <efilib.h>
+
+#include "FileLoader.h"
+
+EFI_STATUS EFIAPI efi_main(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
+{
+    InitializeLib(ImageHandle, SystemTable);
+    SystemTable->BootServices->SetWatchdogTimer(0, 0, 0, NULL);
+    Print(L"Lynx Bootloader © EnderIce2 2022\n");
+    EFI_FILE *Kernel = LoadFile(NULL, L"kernel.fsys", ImageHandle, SystemTable);
+
+    if (Kernel == NULL)
+    {
+        Print(L"Kernel not found\n");
+        while (1)
+            asm("hlt");
+    }
+
+    while (1)
+        asm("hlt");
+    return EFI_SUCCESS;
+}