🚀💾 drippleMini

cryptosbyte · cryptosbyte · commit c628b5e535b0 · 2021-02-26T15:42:16.000Z
diff --git a/Makefile b/Makefile
@@ -0,0 +1,32 @@
+# $@ = target file
+# $< = first dependency
+# $^ = all dependencies
+
+# First rule is the one executed when no parameters are fed to the Makefile
+all: run
+
+# Notice how dependencies are built as needed
+kernel.bin: kernel_entry.o kernel.o
+	/usr/local/i386elfgcc/bin/i386-elf-ld -o $@ -Ttext 0x1000 $^ --oformat binary
+
+kernel_entry.o: kernel_entry.asm
+	nasm $< -f elf -o $@
+
+kernel.o: kernel.c
+	/usr/local/i386elfgcc/bin/i386-elf-gcc -ffreestanding -c $< -o $@
+
+# Rule to disassemble the kernel - may be useful to debug
+kernel.dis: kernel.bin
+	ndisasm -b 32 $< > $@
+
+bootsect.bin: bootsect.asm
+	nasm $< -f bin -o $@
+
+os-image.bin: bootsect.bin kernel.bin
+	cat $^ > $@
+
+run: os-image.bin
+	qemu-system-i386 -fda $<
+
+clean:
+	rm *.bin *.o *.dis
diff --git a/README.md b/README.md
@@ -0,0 +1,11 @@
+# drippleMini OS
+
+A 64 bit operating system made from scratch, using Assembly & C-lang to create kernels and other stuff. 
+**Current version:** `1.0.0-public`
+
+# Running Guide
+| :exclamation:  This is very important   |
+|-----------------------------------------|
+
+### How can I create my own OS?
+One of the main GitHub repositories that helped me quite a lot is the [os-tutorial](https://github.com/cfenollosa/os-tutorial/) one, made by [cfenollosa](https://github.com/cfenollosa). It quite briefly explains what each commands are, in Assembly and how to use them; I also recommend learning the basics of Assembly.
diff --git a/bin/bootsect.bin b/bin/bootsect.bin
diff --git a/bin/kernel.bin b/bin/kernel.bin
diff --git a/bin/kernel.o b/bin/kernel.o
diff --git a/bin/kernel_entry.o b/bin/kernel_entry.o
diff --git a/drippleOS.bin b/drippleOS.bin
diff --git a/os/32bit/gdt.asm b/os/32bit/gdt.asm
@@ -0,0 +1,28 @@
+gdt_start: 
+    dd 0x0
+    dd 0x0
+
+gdt_code: 
+    dw 0xffff 
+    dw 0x0
+    db 0x0       
+    db 10011010b 
+    db 11001111b 
+    db 0x0       
+
+gdt_data:
+    dw 0xffff
+    dw 0x0
+    db 0x0
+    db 10010010b
+    db 11001111b
+    db 0x0
+
+gdt_end:
+
+gdt_descriptor:
+    dw gdt_end - gdt_start - 1 
+    dd gdt_start 
+
+CODE_SEG equ gdt_code - gdt_start
+DATA_SEG equ gdt_data - gdt_start
diff --git a/os/32bit/print.asm b/os/32bit/print.asm
@@ -0,0 +1,25 @@
+[bits 32]
+
+VIDEO_MEMORY equ 0xb8000
+WHITE_ON_BLACK equ 0x0f 
+
+print_str_pm:
+    pusha
+    mov edx, VIDEO_MEMORY
+
+ps_pm_loop:
+    mov al, [ebx]
+    mov ah, WHITE_ON_BLACK
+
+    cmp al, 0 
+    je print_str_pm_done
+
+    mov [edx], ax
+    add ebx, 1 
+    add edx, 2 
+
+    jmp ps_pm_loop
+
+print_str_pm_done:
+    popa
+    ret
diff --git a/os/32bit/switch.asm b/os/32bit/switch.asm
@@ -0,0 +1,22 @@
+[bits 16]
+switch_to_pm:
+    cli 
+    lgdt [gdt_descriptor] 
+    mov eax, cr0
+    or eax, 0x1 
+    mov cr0, eax
+    jmp CODE_SEG:init_pm 
+
+[bits 32]
+init_pm: 
+    mov ax, DATA_SEG 
+    mov ds, ax
+    mov ss, ax
+    mov es, ax
+    mov fs, ax
+    mov gs, ax
+
+    mov ebp, 0x90000
+    mov esp, ebp
+
+    call BEGIN_PM 
diff --git a/os/boot/boot_sect_disk.asm b/os/boot/boot_sect_disk.asm
@@ -0,0 +1,37 @@
+load_disk:
+    pusha
+    push dx
+
+    mov ah, 0x02
+    mov al, dh  
+    mov cl, 0x02
+    mov ch, 0x00
+    mov dh, 0x00 ; dh - head number
+
+    int 0x13      ; BIOS interrupt
+    jc disk_error ; if error (stored in the carry bit)
+
+    pop dx
+    cmp al, dh    ; BIOS also sets 'al' to the # of sectors read. Compare it.
+    jne sectors_error
+    popa
+    ret
+
+
+disk_error:
+    mov bx, DISK_ERROR
+    call print
+    call print_nl
+    mov dh, ah
+    call print_hex
+    jmp disk_loop
+
+sectors_error:
+    mov bx, SECTORS_ERROR
+    call print
+
+disk_loop:
+    jmp $
+
+DISK_ERROR: db "Disk read error", 0
+SECTORS_ERROR: db "Incorrect number of sectors read", 0
diff --git a/os/boot/boot_sect_print.asm b/os/boot/boot_sect_print.asm
@@ -0,0 +1,29 @@
+print:
+    pusha
+
+start:
+    mov al, [bx]
+    cmp al, 0 
+    je completed
+
+    mov ah, 0x0e
+    int 0x10 
+
+    add bx, 1
+    jmp start
+
+completed:
+    popa
+    ret
+
+print_nl:
+    pusha
+    
+    mov ah, 0x0e
+    mov al, 0x0a 
+    int 0x10
+    mov al, 0x0d 
+    int 0x10
+    
+    popa
+    ret
diff --git a/os/boot/boot_sect_print_hex.asm b/os/boot/boot_sect_print_hex.asm
@@ -0,0 +1,32 @@
+print_hex:
+    pusha
+    mov cx, 0
+
+hex_loop:
+    cmp cx, 4
+    je end
+    
+    mov ax, dx 
+    and ax, 0x000f 
+    add al, 0x30 
+    cmp al, 0x39 
+    jle copyPosition 
+    add al, 7
+
+copyPosition:
+    mov bx, HEX_OUT + 5 
+    sub bx, cx  
+    mov [bx], al
+    ror dx, 4 
+
+    add cx, 1
+    jmp hex_loop
+
+end:
+    mov bx, HEX_OUT
+    call print
+    popa
+    ret
+
+HEX_OUT:
+    db '0x0000',0
diff --git a/os/bootsect.asm b/os/bootsect.asm
@@ -0,0 +1,48 @@
+[org 0x7c00]
+KERNEL_OFFSET equ 0x1000 
+
+    mov [BOOT_DRIVE], dl 
+    mov bp, 0x9000
+    mov sp, bp
+
+    mov bx, WARN_REAL_MODE 
+    call print
+    call print_nl
+
+    call load_kernel ; Read KERNEL from DISK
+    call switch_to_pm
+    jmp $
+
+%include "boot/boot_sect_print.asm"
+%include "boot/boot_sect_print_hex.asm"
+%include "boot/boot_sect_disk.asm"
+%include "32bit/gdt.asm"
+%include "32bit/print.asm"
+%include "32bit/switch.asm"
+
+[bits 16]
+load_kernel:
+    mov bx, WARN_LOAD_KERNEL
+    call print
+    call print_nl
+
+    mov bx, KERNEL_OFFSET 
+    mov dh, 2
+    mov dl, [BOOT_DRIVE]
+    call load_disk
+    ret
+
+[bits 32]
+BEGIN_PM:
+    mov ebx, WARN_PROT_MODE
+    call print_str_pm
+    call KERNEL_OFFSET 
+    jmp $ 
+
+BOOT_DRIVE db 0
+WARN_REAL_MODE db "Current: 16bit Real Mode", 0
+WARN_PROT_MODE db "Current: 32bit Protected Mode", 0
+WARN_LOAD_KERNEL db "Current: Loading kernel into memory", 0
+
+times 510 - ($-$$) db 0
+dw 0xaa55
diff --git a/os/kernel.c b/os/kernel.c
@@ -0,0 +1,12 @@
+void entrypoint()
+{
+    // void
+}
+
+void main()
+{
+
+    char* video_memory = (char*) 0xb8000;
+    *video_memory = 'X';
+
+}
diff --git a/os/kernel_entry.asm b/os/kernel_entry.asm
@@ -0,0 +1,4 @@
+[bits 32]
+[extern main]
+call main 
+jmp $
