add build files

.sh

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+sudo apt install make nasm qemu
+# snap install micro --classic
+

LICENSE

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+MIT License
+
+Copyright (c) 2019 chibicitiberiu
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

Makefile

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+ASM=nasm
+
+SRC_DIR=src
+BUILD_DIR=build
+
+$(BUILD_DIR)/main_floppy.img: $(BUILD_DIR)/main.bin
+	cp $(BUILD_DIR)/main.bin $(BUILD_DIR)/main_floppy.img
+	truncate -s 1440k $(BUILD_DIR)/main_floppy.img
+    
+$(BUILD_DIR)/main.bin: $(SRC_DIR)/main.asm
+	$(ASM) $(SRC_DIR)/main.asm -f bin -o $(BUILD_DIR)/main.bin

install_packages.sh

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+sudo apt install make nasm qemu
+

src/main.asm

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+; https://github.com/nanobyte-dev/nanobyte_os/blob/Part1/src/main.asm
+org 0x7C00
+bits 16
+
+
+%define ENDL 0x0D, 0x0A
+
+
+start:
+    jmp main
+
+
+;
+; Prints a string to the screen
+; Params:
+;   - ds:si points to string
+;
+puts:
+    ; save registers we will modify
+    push si
+    push ax
+    push bx
+
+.loop:
+    lodsb               ; loads next character in al
+    or al, al           ; verify if next character is null?
+    jz .done
+
+    mov ah, 0x0E        ; call bios interrupt
+    mov bh, 0           ; set page number to 0
+    int 0x10
+
+    jmp .loop
+
+.done:
+    pop bx
+    pop ax
+    pop si    
+    ret
+    
+
+main:
+    ; setup data segments
+    mov ax, 0           ; can't set ds/es directly
+    mov ds, ax
+    mov es, ax
+    
+    ; setup stack
+    mov ss, ax
+    mov sp, 0x7C00      ; stack grows downwards from where we are loaded in memory
+
+    ; print hello world message
+    mov si, msg_hello
+    call puts
+
+    hlt
+
+.halt
+    jmp .halt
+
+
+
+msg_hello: db 'Hello world!', ENDL, 0
+
+
+times 510-($-$$) db 0
+dw 0AA55h

start-qemu.sh

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+qemu-system-i386 -fda build/main_floppy.img