printf itoa utoa

sys/include/types.h

@@ -16,4 +16,9 @@ typedef char			s8;
 typedef unsigned int		size_t;
 typedef int			ssize_t;
 
+typedef unsigned char *va_list;
+#define va_start(list, param)   (list = (((va_list)&param) + sizeof(param)))
+#define va_arg(list, type)  (*(type *)((list += sizeof(type)) - sizeof(type)))
+#define va_end(list)    (list = NULL)
+
 #endif

sys/lib.c

@@ -1,4 +1,5 @@
 #include <types.h>
+static char strbuf[32];
 
 u32
 strlen(const char *str)
@@ -10,10 +11,82 @@ strlen(const char *str)
 	return i;
 }
 
+char*
+itoa(s32 num, char *str, s32 base)
+{
+	s32 i = 0;
+
+	if (num < 0 && base == 10) {
+		str[i++] = '-';
+		num = -num;
+	}
+
+	while (num != 0) {
+		s32 remainder = num % base;
+		str[i++] = (remainder < 10) ? remainder + '0' : remainder + 'a' - 10;
+		num/=base;
+	}
+
+	str[i] = '\0';
+
+	return str;
+}
+
+char*
+utoa(u32 num, char *str, s32 base)
+{
+	s32 i = 0;
+
+	while (num != 0) {
+		s32 remainder = num % base;
+		str[i++] = (remainder < 10) ? remainder + '0' : remainder + 'a' - 10;
+		num/=base;
+	}
+
+	str[i] = '\0';
+
+	return str;
+}
+
+s32
 printf(const char *format, ...)
 {
-	const u32 len = strlen(format);
+	const u32 len = sizeof(format);
+	va_list list;
+	va_start(list, len);
 
-	vga_write(format, len, 0x0f);
+	for (u32 i = 0; i < len; i++) {
-	return len;
+		if (format[i] == '%') {
+			if (format[i + 1] == 'd' || format[i + 1] == 'i') {
+				//integer numbers
+				const s32 num = va_arg(list, s32);
+				vga_write(itoa(num, strbuf, 10), 1, 0x0f);
+			} else if (format[i + 1] == 'o') {
+				//octal numbers
+				const s32 num = va_arg(list, s32);
+				vga_write(itoa(num, strbuf, 8), 1, 0x0f);
+			} else if (format[i + 1] == 'u') {
+				//unsigned integers
+				const u32 num = va_arg(list, u32);
+				vga_write(utoa(num, strbuf, 10), 1, 0x0f);
+			} else if (format[i + 1] == 'x') {
+				//hexadecimal numbers
+				const u32 num = va_arg(list, u32);
+				vga_write(utoa(num, strbuf, 16), 1, 0x0f);
+			} else if (format[i + 1] == 's') {
+				//strings
+				const char *str = va_arg(list, char*);
+				vga_write(str, strlen(str), 0x0f);
+			} else if (format[i + 1] == 'c') {
+				//one character
+				vga_write(va_arg(list, char), 1, 0x0f);
+			} else if (format[i + 1] == '%') {
+				vga_write('%', 1, 0x0f);
+			}
+		} else if (format[i] == '\\' && format[i + 1] == '%') {
+			vga_write('%', 1, 0x0f);
+		} else {
+			vga_write(format[i], 1, 0x0f);
+		}
+	}
 }

sys/sysinit.c

@@ -11,7 +11,7 @@ sysinit(void)
 	for (s16 i = 0; i < 100; i++) {
 		vga_write(howdy, strlen(howdy), 0x1f);
 		vga_write(howday, strlen(howday), 0x0f);
-	} 
+	}
 
 	vga_write("sid", 3, 0x07);
 	vga_write("did", 3, 0x07);
@@ -47,4 +47,6 @@ sysinit(void)
 "bob", 2003, 0x0F);
 	vga_write("indian", 6, 0x07);
 	vga_write("indian", 6, 0x07);
+
+	printf("%s%x", "Omh", 0x2a);
 }