initial commitHEADmaster

16 files changed, 607 insertions, 0 deletions

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..87e6b93
--- /dev/null
+++ b/README.md
@@ -0,0 +1,32 @@
+## Disclaimer
+-----------------------
+For now, assumes that A20 is already enabled on your device by BIOS.
+
+## Why Bash?
+-----------------------
+I like it more, and feels more customizable than makefile.
+This project is not going to be permanent anyways, just some bootloader.
+
+## Disk Mapping
+-----------------------
+0x0 - 0x200 -> Master Boot Record (MBR)
+0x200 - 0x9ff -> Stage 1
+*  -  * -> Stage 2
+
+## Memory Mapping
+-----------------------
+0x7c00 - 0x7e00 -> BIOS MBR
+0x7e00 - 0x9200 -> stage 1
+
+## Stages
+-----------------------
+- early stage 1 (MBR)
+The only duty of this stage is to load the stage 1 bootloader.
+
+- stage 1
+1. Detects available video memory, and RAM memory.
+2. Switches to 32-bit execution and protected mode.
+
+- stage 2
+1. Switches to 64-bit execution (long mode).
+2. Implements a FAT driver to load a kernel (or OS) file from disk.
diff --git a/TODO b/TODO
new file mode 100644
index 0000000..91af834
--- /dev/null
+++ b/TODO
@@ -0,0 +1,8 @@
+TODO
+- ensure proper checks after mbr extended read
+- request available memory from BIOS in real-mode
+- 64-bit switch
+- FAT filesystem
+- Kernel Loading
+- So basically make a fucking bootloader.
+- Cleanup the linker script a bit.
diff --git a/build.sh b/build.sh
new file mode 100755
index 0000000..bb9c67a
--- /dev/null
+++ b/build.sh
@@ -0,0 +1,231 @@
+#!/bin/bash
+
+set -e
+
+if [ -z "${CROSSCC_i686}" ]; then
+    CROSSCC_i686=i686-elf-gcc
+fi
+
+if [ -z "${CROSSAS_i686}" ]; then
+    CROSSAS_i686=i686-elf-as
+fi
+
+if [ -z "${CROSSCC_x8664}" ]; then
+    CROSSCC_x8664=x86_64-elf-gcc
+fi
+
+if [ -z "${CROSSAS_x8664}" ]; then
+    CROSSAS_x8664=x86_64-elf-as
+fi
+
+if [ -z "${CROSSLD_i686}" ]; then
+    CROSSLD_i686=i686-elf-ld
+fi
+
+if [ -z "${CROSSLD_x8664}" ]; then
+    CROSSLD_x8664=x86_64-elf-ld
+fi
+
+if [ -z "${STAGE1_DIR}" ]; then
+    STAGE1_DIR="./stage1/"
+fi
+
+if [ -z "${STAGE2_DIR}" ]; then
+    STAGE2_DIR="$(pwd)/stage2"
+fi
+
+if [ -z "${BUILD_DIR}" ]; then
+    BUILD_DIR="$(pwd)/build"
+fi
+mkdir -p "${BUILD_DIR}"
+
+if [ -z "${TARGET}" ]; then
+    TARGET="$(pwd)/bootloader"
+fi
+
+GLOBAL_CFLAGS=(-I./include -ffreestanding -m32 -nostdlib)
+
+LINKER_LD="linker.ld"
+
+# Stage 1
+
+STAGE1_LD="${STAGE1_DIR}/linker.ld"
+
+STAGE1_C_FILES=$(find "${STAGE1_DIR}" -name "*.c")
+STAGE1_AS_FILES=$(find "${STAGE1_DIR}" -name "*.S")
+
+STAGE1_AS_TARGET="${BUILD_DIR}/stage1_as.o"
+STAGE1_CC_TARGET="${BUILD_DIR}/stage1_cc.o"
+
+STAGE1_TARGET="${BUILD_DIR}/stage1.bin"
+
+# Stage 2
+
+STAGE2_LD="${STAGE1_DIR}/linker.ld"
+
+STAGE2_C_FILES=$(find "${STAGE2_DIR}" -name "*.c")
+STAGE2_AS_FILES=$(find "${STAGE2_DIR}" -name "*.S")
+
+STAGE2_AS_TARGET="${BUILD_DIR}/stage2_as.o"
+STAGE2_CC_TARGET="${BUILD_DIR}/stage2_cc.o"
+
+STAGE1_DIR="$(pwd)/stage1"
+STAGE2_DIR="$(pwd)/stage2"
+
+function usage {
+    echo -e "Custom build system."
+    echo -e "Available commands:"
+    echo -e "    ${0} all"
+    echo -e "    ${0} run"
+    echo -e "    ${0} build_drive"
+    echo -e "    ${0} clean"
+    echo -e "    ${0} stage1"
+}
+
+function build_lib {
+	macro="$1"
+
+	set -e
+
+	local lib_cfiles=$(find "./lib/" -name "*.c")
+
+	mkdir -p "${BUILD_DIR}/lib"
+	for i in ${lib_cfiles[@]}; do
+		"${CROSSCC_i686}" -m32 -c "$i" "${GLOBAL_CFLAGS[@]}" -o "${BUILD_DIR}/${i}.o" -D${macro}
+		echo -e "    [CC] ${i}"
+	done
+
+	echo "[LIB] Compiled libraries."
+}
+
+function stage1 {
+    set -e
+
+    if [[ -e "${BUILD_DIR}/${STAGE1_DIR}" ]] && [[ -f "${BUILD_DIR}/${STAGE1_DIR}" ]]; then
+	mkdir -p "${BUILD_DIR}/${STAGE1_DIR}"
+	echo -e "Creating the stage 1 build directory ${BUILD_DIR}/${STAGE1_DIR}"
+    fi
+
+    echo -e "Producing stage 1 binaries..."
+
+    if [[ ${#STAGE1_AS_FILES[@]} -gt 0 ]] && [[ -n "${STAGE1_AS_FILES[@]}" ]]; then
+	echo -e "[STAGE1] Found assembly files: "
+	for i in ${STAGE1_AS_FILES[@]}; do
+		mkdir -p "${BUILD_DIR}/${i}"
+		"${CROSSAS_i686}" "$i" -o "${BUILD_DIR}/${i}.o" 
+	    	echo -e "    [AS]: $i"
+	done
+	echo -e "    [AS] Assembled stage 1."
+    else
+	echo -e "[STAGE1] No assembly files were found."
+    fi
+
+    if [[ ${#STAGE1_C_FILES[@]} -gt 0 ]] && [[ -n "${STAGE1_C_FILES[@]}" ]]; then
+	echo -e "[STAGE1] Found C files: "
+	for i in ${STAGE1_C_FILES[@]}; do
+		"${CROSSCC_i686}" -c "$i" -o "${BUILD_DIR}/${i}.o" "${GLOBAL_CFLAGS[@]}"
+		echo -e "    [CC]: $i"
+	done
+	echo -e "    [CC] Compiled stage 1."
+    else
+	echo -e "[STAGE1] No C files were found."
+    fi
+
+    if [[ ${#STAGE1_C_FILES[@]} -eq 0 ]] && [[ ${#STAGE1_AS_FILES[@]} -eq 0 ]]; then
+	echo -e "[STAGE1] No stage1 files were found!"
+	exit 1
+    fi
+
+    echo -e "Stage 1 binaries completed."
+}
+
+function stage2 {
+    if [[ -e "${BUILD_DIR}/${STAGE1_DIR}" ]] && [[ -f "${BUILD_DIR}/${STAGE1_DIR}" ]]; then
+	mkdir -p "${BUILD_DIR}/${STAGE1_DIR}"
+    fi
+
+    ${CROSSAS_i686} "${STAGE2_AS_FILES}" -o "${STAGE2_AS_TARGET}"
+    echo -e "    [AS] Assembled stage 2."
+    ${CROSSCC_x8664} "${STAGE2_C_FILES}" -o "${STAGE2_CC_TARGET}"
+    echo -e "    [CC] Compiled stage 2."
+}
+
+function link {
+	set -e
+
+	local linker_files=()
+
+	echo -e "[LINK] Linking files..."
+
+	for i in $(find "${BUILD_DIR}" -name "*.o"); do
+		linker_files+=("$i")
+		echo -e "    [L] Added: $i"
+	done
+
+	"${CROSSLD_i686}" -T "${LINKER_LD}" "${linker_files[@]}" -o "${STAGE1_TARGET}"
+
+	echo -e "[LINK] Linking complete."
+}
+
+function clean {
+	if [[ -e "${BUILD_DIR}" && -d "${BUILD_DIR}" ]]; then
+		echo -e "[CLEAN] Deleting build/ directory..."
+		rm -rf "${BUILD_DIR}"
+	fi
+   
+	if [[ -e "$(pwd)/disk.img" && -f "$(pwd)/disk.img"  ]]; then
+		echo -e "[CLEAN] Deleting disk.img..."
+		rm "$(pwd)/disk.img"
+	fi
+	echo -e "[CLEAN] Project cleaned."
+}
+
+function build_image {
+	dd if="${STAGE1_TARGET}" of="$(pwd)/disk.img" bs=512 count=15
+}
+
+function run {
+	qemu-system-x86_64 -drive format=raw,file="$(pwd)/disk.img"
+}
+
+function debug {
+	qemu-system-x86_64 -drive format=raw,file="$(pwd)/disk.img" -S -s
+}
+
+function compile {
+    echo "[COMPILE] Compiling and preparing the entire build."
+    clean
+    mkdir -p ./build/
+    build_lib "STAGE1"
+    stage1
+    link
+    build_image
+    echo "[COMPILE] DONE"
+}
+
+function run {
+    qemu-system-x86_64 -drive format=raw,file=disk.img
+}
+
+case "$1" in
+    "all") compile ;;
+    "run") compile && run ;;
+    "debug") compile && debug ;;
+    "stage1") stage1 ;;
+    "build_drive") build_image ;;
+    "clean") clean ;;
+    "help"|"usage")
+	usage
+	exit 0
+	;;
+    "")
+	echo -e "You must specify a command."
+	echo -e "Type '${0} usage' or '${0} help' for more information."
+	exit 1
+	;;
+    *)
+	echo -e "Command not found: '${1}'"
+	usage
+	exit 1
+	;;
+esac
diff --git a/include/defs.h b/include/defs.h
new file mode 100644
index 0000000..9932af1
--- /dev/null
+++ b/include/defs.h
@@ -0,0 +1,14 @@
+#ifndef DEFS_H
+#define DEFS_H
+
+#ifdef STAGE1
+	#define BLSEC_TEXT __attribute__((section(".stage1.text")))
+	#define BLSEC_DATA __attribute__((section(".stage1.data")))
+#elif STAGE2
+	#define BLSEC_DATA __attribute__((section(".stage2.data")))
+	#define BLSEC_DATA __attribute__((section(".stage2.data")))
+#else
+	#error "You must define a stage to compile the libraries!"
+#endif
+
+#endif // DEFS_H
diff --git a/include/printk.h b/include/printk.h
new file mode 100644
index 0000000..08a2778
--- /dev/null
+++ b/include/printk.h
@@ -0,0 +1,10 @@
+#ifndef PRINTK_H
+#define PRINTK_H
+
+#include <defs.h>
+
+#include <stdint.h>
+
+void write(char *str, uint8_t color) BLSEC_TEXT;
+
+#endif
diff --git a/include/string.h b/include/string.h
new file mode 100644
index 0000000..7c1caa5
--- /dev/null
+++ b/include/string.h
@@ -0,0 +1,9 @@
+#ifndef STRING_H
+#define STRING_H
+
+#include <defs.h>
+#include <stddef.h>
+
+size_t strlen(char* s) BLSEC_TEXT;
+
+#endif
diff --git a/include/vga.h b/include/vga.h
new file mode 100644
index 0000000..66a5441
--- /dev/null
+++ b/include/vga.h
@@ -0,0 +1,16 @@
+#ifndef VGA_H
+#define VGA_H
+
+#include <defs.h>
+#include <stdint.h>
+
+#define VGA_MEMORY_ADDR (volatile uint16_t*)0xB8000;
+
+#define MAX_WIDTH 80
+#define MAX_HEIGHT 25
+
+void vga_setup(int maxw, int maxh) BLSEC_TEXT;
+uint8_t vga_color(uint8_t fg, uint8_t bg) BLSEC_TEXT;
+void vga_put(uint32_t x, uint32_t y, unsigned char uc, uint8_t color) BLSEC_TEXT;
+
+#endif
diff --git a/lib/printk.c b/lib/printk.c
new file mode 100644
index 0000000..e2ae612
--- /dev/null
+++ b/lib/printk.c
@@ -0,0 +1,36 @@
+#include <printk.h>
+
+#include <string.h>
+#include <vga.h>
+
+#include <stddef.h>
+
+void write(char *s, uint8_t color)
+{
+	static size_t x BLSEC_DATA = 0;
+	static size_t y BLSEC_DATA = 0;
+	
+	size_t len = strlen(s);
+	for (size_t i = 0; i < len; i++) {
+
+		if (s[i] == '\n') {
+			y++;
+			x = 0;
+			continue;
+		}
+	
+		vga_put(x, y, s[i], color);
+
+		if (y >= MAX_HEIGHT)
+			return; //TODO: To be implemented.
+
+	
+		if (x >= MAX_WIDTH) {
+			y++;
+			x = 0;
+		} else {
+			x++;
+		}
+
+	}
+}
diff --git a/lib/string.c b/lib/string.c
new file mode 100644
index 0000000..b48ffc0
--- /dev/null
+++ b/lib/string.c
@@ -0,0 +1,13 @@
+#include <string.h>
+
+size_t strlen(char* s)
+{
+	int pos=0;
+	
+	while (s[pos]) {
+
+		pos++;
+	}
+
+	return pos;
+}
diff --git a/lib/vga.c b/lib/vga.c
new file mode 100644
index 0000000..9727025
--- /dev/null
+++ b/lib/vga.c
@@ -0,0 +1,23 @@
+#include <vga.h>
+#include <stddef.h>
+
+static uint16_t* vga_buffer BLSEC_DATA = VGA_MEMORY_ADDR;
+
+void vga_setup(int xmax, int ymax)
+{
+	for (size_t i = 0; i < MAX_WIDTH; i++) {
+		for (size_t j = 0; j < MAX_HEIGHT; j++) {
+			vga_put(i, j, ' ', 0);
+		}		
+	}
+}
+
+uint8_t vga_color(uint8_t fg, uint8_t bg)
+{
+	return (uint8_t) fg | (uint8_t) bg << 4;
+}
+
+void vga_put(uint32_t x, uint32_t y, unsigned char uc, uint8_t color)
+{
+	vga_buffer[y*80+x] = (uint16_t) uc | (uint16_t) color << 8;
+}
diff --git a/linker.ld b/linker.ld
new file mode 100644
index 0000000..65d8abd
--- /dev/null
+++ b/linker.ld
@@ -0,0 +1,45 @@
+ENTRY(_start)
+OUTPUT_FORMAT("binary")
+
+SECTIONS {
+	 /DISCARD/ : {
+		*(.comment)
+		*(.data)
+	 }
+
+	 . = 0x7c00;
+	 
+	 .mbr 0x7c00 : AT(0x0) {
+	      *(.mbr)
+	 }
+
+	 .mbr_data 0x7d00 : AT(0x100) {
+	      *(.mbr_data)
+	 }
+	 
+	 . = 0x7c00 + 0x1FE;
+	 .mbr_magic : AT(0x1FE) {
+	 	 BYTE(0x55)
+	 	 BYTE(0xAA)
+	 }
+
+	 .stage1 0x7e00 : AT(0x200) {
+	 	*(.stage1)
+		*(.stage1_ro)
+		*(.rodata*)
+	 	*(.stage1.text)
+	 	*(.stage1.data)
+	 }
+
+	 pad 0x91ff : AT(0x1600) { /* 11th block */
+	 	BYTE(0)
+	 }
+	
+	_stack_start = .;
+
+	 .stack 0x99ff : AT(0x1cff) { /* 15th block */
+		BYTE(0)
+	 }
+
+	 _stack_end = .;
+}
diff --git a/stage1/32bit.c b/stage1/32bit.c
new file mode 100644
index 0000000..1e4a7ef
--- /dev/null
+++ b/stage1/32bit.c
@@ -0,0 +1,22 @@
+#define STAGE1
+#include "stage1.h"
+
+#include <stddef.h>
+#include <stdint.h>
+#include <vga.h>
+#include <printk.h>
+#include <string.h>
+
+void centry(void)
+{
+	vga_setup(25,80);
+
+	uint8_t color = vga_color(0xF, 0);
+
+	write("Bootloader is set to 32-bit mode.", color);
+
+	while (1) {
+		asm ("cli");
+		asm ("hlt");
+	}
+}
diff --git a/stage1/32bit.o b/stage1/32bit.o
new file mode 100755
index 0000000..bd221e3
--- /dev/null
+++ b/stage1/32bit.o
diff --git a/stage1/entry.S b/stage1/entry.S
new file mode 100644
index 0000000..81390d9
--- /dev/null
+++ b/stage1/entry.S
@@ -0,0 +1,56 @@
+.intel_syntax noprefix
+
+.section .mbr, "ax"
+
+.extern _stack_start
+.extern _stack_end
+.extern centry
+
+.global _start
+.code16
+	
+_start:	
+	xor ax, ax
+	mov ds, ax
+	jmp 0x0:_entry
+
+_entry:
+	mov ah, 0x42
+	mov si, offset dap
+	
+	int 0x13
+
+	jc error
+
+	mov ah, 0x0E
+	mov al, 'S'
+	mov bh, 0x0
+	mov bl, 0x0
+
+	int 0x10
+
+	jmp 0x0:stage1_sector
+	
+	cli
+	hlt
+
+error:
+	mov ah, 0x0e
+	mov al, 'E'
+	mov bh, 0x0
+	mov bl, 0x0
+
+	int 0x10
+
+	cli
+	hlt
+
+.section .mbr_data, "aw"
+
+dap:
+	.byte 0x10
+	.byte 0
+	.word 14
+	.word 0x7e00
+	.word 0x0
+	.quad 1
diff --git a/stage1/stage1.S b/stage1/stage1.S
new file mode 100644
index 0000000..e11e36b
--- /dev/null
+++ b/stage1/stage1.S
@@ -0,0 +1,84 @@
+.intel_syntax noprefix
+.code16
+
+.extern _stack_start
+.extern _stack_end
+
+.global stage1_sector
+
+.section .stage1, "ax"
+
+stage1_sector:
+	xor ax, ax
+	
+	mov ah, 0x0e
+	mov al, 'C'
+	mov bh, 0x0
+	mov bl, 0x0
+
+	int 0x10
+	
+	cli
+
+	lgdt gdtr
+	
+	mov eax, cr0
+	or eax, (1 << 0)
+	mov cr0, eax
+
+	jmp 0x8:_32_start
+	
+	cli
+	hlt
+
+.code32
+_32_start:
+	mov eax, 0x10
+
+	mov ds, ax
+	mov ss, ax
+	mov es, ax
+	mov fs, ax
+	mov gs, ax
+	
+	jmp 0x8:_32_entry
+
+	cli
+	hlt
+	
+_32_entry:
+	mov eax, offset _stack_start
+	mov ebp, eax
+	mov eax, offset _stack_end
+	mov esp, eax 
+
+	call centry
+
+	cli
+	hlt
+
+.code16
+.section .stage1_ro, "aw"
+
+gdt:
+	.quad 0x0 // Null seg
+	
+	.word 0xFFFF // Code seg
+	.word 0x0000
+	.byte 0x0
+	.byte 0b10011011 // A=1 RW=1 DC=0 E=1 S=1 DPL=00 P=1
+	.byte 0b11001111
+	.byte 0x0000
+
+	.word 0xFFFF // Data Seg
+	.word 0x0000
+	.byte 0x0
+	.byte 0b10010011 // A=1 RW=1 DC=0 E=0 S=1 DPL=00 P=1
+	.byte 0b11001111
+	.byte 0x0000
+
+end_gdt:
+
+gdtr:
+	.word end_gdt - gdt - 1
+	.long gdt
diff --git a/stage1/stage1.h b/stage1/stage1.h
new file mode 100644
index 0000000..cf29acb
--- /dev/null
+++ b/stage1/stage1.h
@@ -0,0 +1,8 @@
+#ifndef STAGE1_H
+#define STAGE1_H
+
+#include <defs.h>
+
+void centry(void) BLSEC_TEXT;
+
+#endif