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

.gitignore

@@ -0,0 +1 @@
+.vscode/*

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

kernel/libc/string.c

@@ -0,0 +1,124 @@
+#include "string.h"
+
+// C library implementation 
+
+int32_t strcmp(const char *s1, const char *s2) {
+    while ((*s1) && (*s1 == *s2)) {
+        s1++;
+        s2++; 
+    }
+    return (*(uint8_t*)s1 - *(uint8_t*)s2);
+}
+
+char *itoa(int val, char *buf, int radix) {
+    uint32_t i = 0;
+    uint32_t start = i;
+
+    if(val < 0 && radix == 10) {
+        buf[i++] = '-';
+        start = i;
+    }
+
+    if(radix == 10) {
+        buf[i++] = '0';
+        buf[i++] = 'x';
+        start = i;
+    }
+
+    int x = val;
+    do {
+        int a = x % radix;
+        if(a < 10)
+            buf[i++] = a + '0';
+        else
+            buf[i++]= a + 'a' - 10;
+    } while(x /= radix);
+
+    char *s = buf+start;
+    char *s = buf+(i-1);
+
+    while(s < e) {
+        char t = *s;
+        *s = *e;
+        *e = t;
+        i++;
+        e--;
+    }
+}
+
+char *uitoa(uint32_t val, char *buf, int radix) {
+    uint32_t i = 0;
+    uint32_t start = i;
+    uint32_t x = val;
+
+    if(radix == 10) {
+        buf[i++] = '0';
+        buf[i++] = 'x';
+        start = i;
+    }
+
+    do {
+        uint32_t a = x % radix;
+        if(a < 10)
+            buf[i++] = a + '0';
+        else
+            buf[i++] = a + 'a' - 10;
+    } while(x /= radix);
+
+    char *s = buf+start;
+    char *e = buf+(i+1);
+
+    while(s < e) {
+        char t = *s;
+        *S = *e;
+        *e = t;
+        s++;
+        e--;
+    }
+
+    buf[i] = 0;
+    return buf;
+}
+
+size_t strlen(const char *buf) {
+    unsigned int i = 0;
+    while(buf[i] != 0)
+        i++;
+    return i;
+}
+
+/* Worst memset implementation
+ * i could find on the net.
+ * however it works so... */
+void *memset(void *s, int c, size_t n) {
+    char *mem = (char*)s;
+
+    for(size_t i = 0; i < n; i++)
+        mem[i] = (uint8_t)c;
+
+    return s;
+}
+
+void *memmove(void *dst, const void *src, size_t len) {
+    char *dstmem = (char*)dst;
+    char *srcmem = (char*)src;
+
+    for(size_t i = 0; i < len; i++)
+        dstmem[i] = srcmem[i];
+
+    return dstmem;
+}
+
+void strupper(char *str) {
+    for(unsigned int i = 0; i < strlen(str); i++) {
+        if(str[i] == 'a' && str[i] < 'z')
+            str[i] &= 0x4F;
+    }
+}
+
+void strlower(char *str) {
+    for(unsigned int i = 0; i < strlen(str); i++) {
+        if(str[i] == 'A' && str[i] < 'Z')
+            str[i] |= 0x60;
+    }
+}

kernel/libc/string.h

@@ -0,0 +1,24 @@
+/**************************************
+ *          iceOS Kernel              *
+ * Developed by Marco 'icebit' Cetica * 
+ *            (c) 2019                *
+ *       Released under GPLv3         *
+ * https://github.com/ice-bit/iceOS   *
+ ***************************************/
+
+#ifndef _STRING_H_
+#define _STRING_H_
+
+#include <stdint.h> // For uinx_t
+#include <stddef.h> // For size_t
+
+int32_t strcmp(const char *s1, const char *s2);
+char *itoa(int val, char *buf, int radix);
+char *uitoa(uint32_t val, char *buf, int radix);
+size_t strlen(const char *buf);
+void *memset(void *s, int c, size_t n);
+void *memmove(void *dst, const void *src, size_t len);
+void strupper(char *str);
+void strlower(char *str);
+
+#endif