Add string and monitor write hex and dec functions

Makefile

@@ -4,7 +4,7 @@
 BIN = bin
 SRC = src
 CC = gcc
-CFLAGS = -Wall -Wno-main -fno-builtin -fno-stack-protector -m32 -nostdlib -nostdinc -std=gnu99 -ggdb3
+CFLAGS = -Wall -ffreestanding -m32 -std=gnu99 -ggdb3
 LINK = ld
 LINKFLAGS = -melf_i386 -Tlink.ld
 CASM = nasm

src/common.c

@@ -17,24 +17,58 @@ u16int inw(u16int port) {
 }
 
 void memcpy(u8int *dest, const u8int *src, u32int len) {
-    // TODO Implement
+    const u8int *sp = (const u8int *)src;
+    u8int *dp = (u8int *)dest;
+
+    while (len != 0) {
+        *dp++ = *sp++;
+        --len;
+    }
 }
 
 void memset(u8int *dest, u8int val, u32int len) {
-    // TODO Implement
+    u8int *temp = (u8int *)dest;
+
+    while (len != 0) {
+        *temp++ = val;
+        --len;
+    }
 }
 
 int strcmp(char *str1, char *str2) {
-    // TODO Implement
-    return 0;
+    int failed = 0;
+    int i = 0;
+    while (str1[i] != '\0' && str2[i] != '\0') {
+        if(str1[i] != str2[i]) {
+            failed = 1;
+            break;
+        }
+        ++i;
+    }
+
+    if ((str1[i] == '\0' && str2[i] != '\0') || (str1[i] != '\0' && str2[i] == '\0')) {
+        failed = 1;
+    }
+
+    return failed;
 }
 
 char *strcpy(char *dest, const char *src) {
-    // TODO Implement
+    do {
+      *dest++ = *src++;
+    } while (*src != 0);
+
     return dest;
 }
 
 char *strcat(char *dest, const char *src) {
-    // TODO Implement
+    while (*dest != 0) {
+        *dest = *dest + 1;
+    }
+
+    do {
+        *dest++ = *src++;
+    } while (*src != 0);
+
     return dest;
 }

src/common.h

@@ -2,6 +2,8 @@
 
 #pragma once
 
+#include <stddef.h>
+
 // typedefs to standardise sizes across platforms, written for 32-bit x86
 typedef unsigned int   u32int;
 typedef          int   s32int;

src/main.c

@@ -4,7 +4,9 @@ struct multiboot;
 
 int main(struct multiboot *mboot_ptr) {
     monitor_clear();
-    monitor_write("Welcome to Tyr, the one-handed OS!");
+    monitor_write("Welcome to Tyr (");
+    monitor_write_hex(0x547972);
+    monitor_write("), the one-handed OS!");
 
     return 0;
 }

src/monitor.c

@@ -107,9 +107,55 @@ void monitor_write(char *c) {
 }
 
 void monitor_write_hex(u32int n) {
-    // TODO Implement
+    s32int tmp;
+    monitor_write("0x");
+
+    char noZeroes = 1;
+    for (int i = 28; i > 0; i -= 4) {
+        tmp = (n >> i) & 0xF;
+        if (tmp == 0 && noZeroes != 0) {
+            continue;
+        }
+
+        noZeroes = 0;
+        if (tmp >= 0xA) {
+            monitor_put(tmp - 0xA + 'A');
+        } else {
+            monitor_put(tmp + '0');
+        }
+    }
+
+    tmp = n & 0xF;
+    if (tmp >= 0xA) {
+        monitor_put(tmp - 0xA + 'A');
+    } else {
+        monitor_put(tmp + '0');
+    }
 }
 
 void monitor_write_dec(u32int n) {
-    // TODO Implement
+    if (n == 0) {
+        monitor_put('0');
+        return;
+    }
+
+    char c[32];
+
+    s32int acc = n;
+    int i = 0;
+    while (acc > 0) {
+        c[i] = '0' + acc%10;
+        acc /= 10;
+        ++i;
+    }
+    c[i] = 0;
+
+    char c2[32];
+    c2[i--] = 0;
+    int j = 0;
+    while(i >= 0) {
+        c2[i--] = c[j++];
+    }
+
+    monitor_write(c2);
 }