Added multiboot header, ports methods and added new part of libc(string)

kernel/cpu/Makefile

@@ -0,0 +1,8 @@
+OBJS = multiboot.asm.o kernel_load.asm.o ports.asm.o
+
+ASM = nasm
+ASMFLAGS = -f elf
+
+all: $(OBJS)
+%.asm.o:
+	$(ASM) $(ASMFLAGS) $< -o $@

kernel/cpu/kernel_load.asm

@@ -0,0 +1,25 @@
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;             iceOS Kernel            ;
+; Developed by Marco 'icebit' Cetica  ;
+;              (c) 2019               ;
+;        Released under GPLv3         ;
+;   https://github.com/ice-bit/iceOS  ;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+global kernel_loader
+extern main
+
+section .text
+kernel_loader:
+    mov esp, kernel_stack + KERNEL_STACK_SZ ; Stack pointer
+    push ebx
+    call main ; jump to kernel's main function
+.loop:
+    jmp .loop ; endless loop
+
+KERNEL_STACK_SZ equ 4096 ; 4 KB for the stack
+
+section .bss
+align 4
+kernel_stack:
+    resb KERNEL_STACK_SZ ; Reserver 4 KB

kernel/cpu/multiboot.asm

@@ -0,0 +1,20 @@
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;             iceOS Kernel            ;
+; Developed by Marco 'icebit' Cetica  ;
+;              (c) 2019               ;
+;        Released under GPLv3         ;
+;   https://github.com/ice-bit/iceOS  ;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+section .multiboot
+head_s:
+    dd 0xe85250d6       ; Magic number
+    dd 0                ; Code for protected mode
+    dd head_e - head_s  ; Header length
+    dd 0x100000000 - (0xe85250d6 + 0 + (head_e - head_s)) ; Checksum of above
+
+    ; Various flags
+    dw 0 ; type
+    dw 0 ; flags
+    dd 0 ; size
+head_e:

kernel/cpu/ports.asm

@@ -0,0 +1,21 @@
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;             iceOS Kernel            ;
+; Developed by Marco 'icebit' Cetica  ;
+;              (c) 2019               ;
+;        Released under GPLv3         ;
+;   https://github.com/ice-bit/iceOS  ;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+global outb ; Output from port
+global inb  ; Input to port
+
+outb:
+    mov al, [esp + 3]
+    mov dx, [esp + 4]
+    out dx, al
+    ret
+
+inb:
+    mov dx, [esp]
+    in al, dx
+    ret