Finally, bootable kernel bare bones!

Makefile

@@ -1,9 +1,16 @@
+.PHONY: quark
+quark: build-dir kernel
+
+include config/.conf
 include scripts/toolchain.mk
-
-BUILD_DIR?=build/
-
-quark: build-dir $(BUILD_DIR)/quark
+include scripts/kernel.mk
+include scripts/run.mk
 
 .PHONY: build-dir
 build-dir:
 	@mkdir -p $(BUILD_DIR)
+	@echo -e $(ARROW) "Created build directory"
+
+.PHONY: clean
+clean:
+	@rm -rf $(BUILD_DIR)/**

config/.conf

@@ -0,0 +1,20 @@
+# CONFIG #
+
+BUILD_DIR ?= $(abspath build/)
+
+TARGET = i686-elf
+TARGET_ASM = nasm
+TARGET_ASMFLAGS =
+TARGET_CFLAGS = -std=c99 -g
+TARGET_CC = $(TARGET)-gcc
+TARGET_CXX = $(TARGET)-g++
+TARGET_LD = $(TARGET)-gcc
+TARGET_LINKFLAGS =
+TARGET_LIBS =
+
+BINUTILS_VERSION = 2.37
+BINUTILS_URL = https://ftp.gnu.org/gnu/binutils/binutils-$(BINUTILS_VERSION).tar.xz
+GCC_VERSION = 11.1.0
+GCC_URL = https://ftp.gnu.org/gnu/gcc/gcc-$(GCC_VERSION)/gcc-$(GCC_VERSION).tar.gz
+
+ARROW = "\x1b[32m-->\x1b[0m"

config/toolchain.conf

@@ -1,15 +0,0 @@
-# TOOLCHAIN CONFIGURATION FILE
-
-export TARGET = i686-elf
-export TARGET_ASM = nasm
-export TARGET_ASMFLAGS =
-export TARGET_CFLAGS = -std=c99 -g
-export TARGET_CC = $(TARGET)-gcc
-export TARGET_CXX = $(TARGET)-g++
-export TARGET_LD = $(TARGET)-gcc
-export TARGET_LINKFLAGS =
-export TARGET_LIBS =
-BINUTILS_VERSION = 2.37
-BINUTILS_URL = https://ftp.gnu.org/gnu/binutils/binutils-$(BINUTILS_VERSION).tar.xz
-GCC_VERSION = 11.1.0
-GCC_URL = https://ftp.gnu.org/gnu/gcc/gcc-$(GCC_VERSION)/gcc-$(GCC_VERSION).tar.gz

scripts/kernel.ld

@@ -0,0 +1,25 @@
+ENTRY(_start)
+phys = 0x00100000;
+
+SECTIONS{
+    .text phys : AT(phys){
+        code = .;
+        *(.text)
+        *(.rodata)
+        . = ALIGN(4096);
+    }
+
+    .data : AT(phys + (data - code)){
+        data = .;
+        *(.data)
+        . = ALIGN(4096);
+    }
+
+    .bss : AT(phys + (bss - code)){
+        bss = .;
+        *(.bss)
+        . = ALIGN(4096);
+    }
+
+    end = .;
+}

scripts/kernel.mk

@@ -0,0 +1,23 @@
+.PHONY: kernel
+kernel: $(BUILD_DIR)/kernel.bin
+
+HEADERS_C = $(shell find src/kernel -type f -name "*.h")
+SOURCES_C = $(shell find src/kernel -type f -name "*.c")
+OBJECTS_C = $(patsubst src/kernel/%.c, $(BUILD_DIR)/kernel/c/%.obj, $(SOURCES_C))
+HEADERS_ASM = $(shell find src/kernel -type f -name "*.inc")
+SOURCES_ASM = $(shell find src/kernel -type f -name "*.asm")
+OBJECTS_ASM = $(patsubst src/kernel/%.asm, $(BUILD_DIR)/kernel/asm/%.obj, $(SOURCES_ASM))
+
+$(BUILD_DIR)/kernel.bin: $(OBJECTS_ASM) $(OBJECTS_C)
+	@$(TARGET_LD) $(TARGET_LINKFLAGS) -T scripts/kernel.ld -nostdlib -Wl,-Map=$(BUILD_DIR)/kernel.map -o $@ $^ $(TARGET_LIBS) -lgcc
+	@echo -e $(ARROW) "Created $(basename $@)"
+
+$(BUILD_DIR)/kernel/c/%.obj: src/kernel/%.c $(HEADERS_C)
+	@mkdir -p $(@D)
+	@$(TARGET_CC) $(TARGET_CFLAGS) -ffreestanding -nostdlib -c -o $@ $<
+	@echo -e $(ARROW) "Compiled $<"
+
+$(BUILD_DIR)/kernel/asm/%.obj: src/kernel/%.asm $(HEADERS_ASM)
+	@mkdir -p $(@D)
+	@$(TARGET_ASM) $(TARGET_ASMFLAGS) -f elf -o $@ $<
+	@echo -e $(ARROW) "Assembled $<"

scripts/run.mk

@@ -0,0 +1,8 @@
+.PHONY: run
+run: quark run-qemu
+
+.PHONY: run-qemu
+run-qemu:
+	@echo -e $(ARROW) "Running on qemu..."
+	@qemu-system-i386 -kernel $(BUILD_DIR)/kernel.bin
+	@echo -e $(ARROW) "Finished run"

scripts/toolchain.mk

@@ -1,5 +1,3 @@
-include config/toolchain.conf
-
 TOOLCHAIN_PREFIX = $(abspath toolchain/$(TARGET))
 export PATH := $(TOOLCHAIN_PREFIX)/bin:$(PATH)
 

src/kernel/arch/i686/io.asm

@@ -0,0 +1,31 @@
+global i686_inb
+i686_inb:
+    [bits 32]
+    mov dx, [esp + 4]
+    xor eax, eax
+    in al, dx
+    ret
+
+global i686_outb
+i686_outb:
+    [bits 32]
+    mov dx, [esp + 4]
+    mov al, [esp + 8]
+    out dx, al
+    ret
+
+global i686_inw
+i686_inw:
+    [bits 32]
+    mov dx, [esp + 4]
+    xor eax, eax
+    in ax, dx
+    ret
+
+global i686_outw
+i686_outw:
+    [bits 32]
+    mov dx, [esp + 4]
+    mov ax, [esp + 8]
+    out dx, ax
+    ret

src/kernel/arch/i686/io.h

@@ -0,0 +1,6 @@
+#include <stdint.h>
+
+uint8_t __attribute__((cdecl)) i686_inb(uint16_t port);
+void __attribute__((cdecl)) i686_outb(uint16_t port, uint8_t value);
+uint16_t __attribute__((cdecl)) i686_inw(uint16_t port);
+void __attribute__((cdecl)) i686_outw(uint16_t port, uint16_t value);

src/kernel/entry.asm

@@ -0,0 +1,34 @@
+[bits 32]
+extern kmain
+extern i686_outw
+global _start
+
+_start:
+    mov esp, _sys_stack
+    jmp call_kmain
+
+; Multiboot header
+align 4
+mboot:
+    ; Some macros
+    MULTIBOOT_PAGE_ALIGN equ 1<<0
+    MULTIBOOT_MEMORY_INFO equ 1<<1
+    MULTIBOOT_HEADER_MAGIC equ 0x1BADB002
+    MULTIBOOT_HEADER_FLAGS equ MULTIBOOT_PAGE_ALIGN | MULTIBOOT_MEMORY_INFO
+    MULTIBOOT_CHECKSUM equ -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
+
+    ; The actual header
+    dd MULTIBOOT_HEADER_MAGIC
+    dd MULTIBOOT_HEADER_FLAGS
+    dd MULTIBOOT_CHECKSUM
+
+call_kmain:
+    call kmain
+    push 0x2000
+    push 0x604
+    call i686_outw
+    jmp $
+
+section .bss
+    resb 8192 ; For the stack
+_sys_stack:

src/kernel/main.c

@@ -0,0 +1,7 @@
+#include <stdint.h>
+#include "arch/i686/io.h"
+
+void __attribute__((cdecl)) kmain(uint64_t magic, uint64_t addr){
+    char *mem = (char *)0xB8000; // Screen memory address (when on text mode)
+    for(int i = 0; 1; i++) mem[i] = 88; // Fill screen with Blue 'X' characters over pink background 
+}