Write vsnprintf() implementation

kernel/include/kernel.h

@@ -8,9 +8,10 @@
  * Variable arguments
  */
 typedef void* va_list;
+#define __va_align(size)	((size + sizeof(int) - 1) & ~(sizeof(int) - 1))
 #define va_start(ap, param)	(void)((ap) = (char*)(&(param) + 1))
 #define va_end(ap)		(void)((ap) = 0)
-#define va_arg(ap, type) (((type*)((ap) = ((ap) + sizeof(type))))[-1])
+#define va_arg(ap, type)	(*(type*)(((ap) += __va_align(sizeof(type))) - sizeof(type)))
 
 /*
  * Utility macros
@@ -67,6 +68,11 @@ typedef int32_t		intptr_t;
 #define true 1
 #define false 0
 
+/*
+ * Linker defined values
+ */
+extern uint32_t __kernel_start, __kernel_end;
+
 /*
  * Logging and errors
  */

kernel/include/vsnprintf.h

@@ -0,0 +1,8 @@
+#ifndef _VSNPRINTF_H
+#define _VSNPRINTF_H
+
+#include <kernel.h>
+
+int vsnprintf(char* buf, size_t len, char* fmt, va_list args);
+
+#endif

kernel/src/entry.s

@@ -31,6 +31,7 @@ global _start
 extern kmain
 _start:
 	mov esp, stack_top	; Setup stack
+	push eax
 	push ebx
 	call kmain		; Call kernel main
 

kernel/src/kernel.c

@@ -1,4 +1,4 @@
-#include <multiboot.h>
+#include <bootloader.h>
 #include <kernel.h>
 #include <serial.h>
 #include <pmm.h>
@@ -6,43 +6,30 @@
 
 #define _hlt()	while (1) __asm__ volatile ("cli; hlt");
 
-char* itoa(uint8_t n) {
-	static char str[32];
-	int i = sizeof(str) - 2;
-	while (n) {
-		str[i--] = (n % 10) + '0';
-		n /= 10;
-	}
-	str[sizeof(str) - 1] = '\0';
-	return &str[i+1];
-}
-
 __noreturn
-void kmain(void* ptr) {
-	multiboot_info_t* mbi = ptr;
+void kmain(void* ptr, uint32_t magic) {
+	// Init with MultiBoot 1, this populates the global bootloader struct
+	//if (boot_init(BOOT_MB1, ptr, magic) != 0) panic("Unsupporred bootloader.");
 
 	// Serial console for debugging
 	serial_init(COM1);
 	serial_puts(COM1, "\x1b[0H\x1b[Jkern.\n");
 
-	// Check if we have a valid memmap
-	if (!(mbi->flags >> 6 & 1)) {
-		panic("Invalid memory map.");
-	}
-
 	// VGA tty thingy
 	tty_init();
-	tty_puts("kern.");
+	tty_puts("kern.\n\n");
 
 	// Memory manager init
 	// pmm_init();
 	// vmm_init();
 
-	// x86 shit
 	// gdt_init();
 	// isr_init();
+	// pag_init();
 
-	/* TODO: Commeted out stuff */
+	debugf("Basic initialization complete!\n");
+	
+	/* TODO: Commented out stuff */
 
 	panic("kmain() reached end.");
 }

kernel/src/serial.c

@@ -1,3 +1,4 @@
+#include <vsnprintf.h>
 #include <kernel.h>
 #include <system.h>
 #include <serial.h>
@@ -51,3 +52,18 @@ void serial_puts(int dev, char* s) {
 	serial_write(dev, s, len);
 }
 
+int debugf(char* fmt, ...) {
+	va_list args;
+	va_start(args, fmt);
+	int ret = vdebugf(fmt, args);
+	va_end(args);
+	return ret;
+}
+
+int vdebugf(char* fmt, va_list args) {
+	static char buf[DF_BUF_LEN];
+	int ret = vsnprintf(buf, DF_BUF_LEN, fmt, args);
+	serial_puts(COM1, buf);
+	return ret;
+}
+

kernel/src/tty.c

@@ -89,7 +89,7 @@ scroll_check:
 
 void tty_write(char* buf, size_t len) {
 	ctx.updateWait = len - 1;
-	for (int i = 0; i < len; i++) tty_putc(buf[i]);
+	for (size_t i = 0; i < len; i++) tty_putc(buf[i]);
 }
 
 void tty_puts(char* s) {

kernel/src/vsnprintf.c

@@ -0,0 +1,93 @@
+#include <kernel.h>
+#include <vsnprintf.h>
+
+int pf_isdigit(char c) {
+	if (c >= '0' && c <= '9') return 1;
+	return 0;
+}
+
+char* pf_itoa(uint32_t num, uint8_t base) {
+	static char buf[32];
+	
+	if (base == 0 || base > 16) return NULL;
+	
+	if (num == 0) {
+		buf[0] = '0';
+		buf[1] = '\0';
+		return &buf[0];
+	}
+
+	int i;
+	for (i = 30; num && i; i--, num /= base) {
+		buf[i] = "0123456789abcdef"[num % base];	
+	}
+	
+	return &buf[i + 1];
+}
+
+char* pf_ftoa(float f) {
+	return NULL;
+}
+
+int vsnprintf(char* buf, size_t len, char* fmt, va_list args) {
+	size_t i = 0;
+
+	while (*fmt != '\0' && i < len) {
+		if (*fmt != '%') {
+			if (i < len) buf[i++] = *fmt++;
+			continue;
+		}
+
+		fmt++; // Consume the '%'
+		if (*fmt == '\0') {
+			if (i < len) buf[i++] = '%';
+			break;
+		}
+
+		// Parse the format specifier
+		int width = 0;
+		char pad = ' ';
+
+		if (pf_isdigit(*fmt)) {
+			if (*fmt == '0') { pad = '0'; fmt++; }
+
+			while (pf_isdigit(*fmt)) {
+				width *= 10;
+				width += *fmt++ - '0';
+			}
+		}
+
+		char* s;
+		switch (*fmt) {
+		case 'c': // Char
+			if (i < len) buf[i++] = (char)va_arg(args, int);
+			break;
+		case 'd': // Int (TODO: %d for signed, %u for unsigned
+			s = pf_itoa(va_arg(args, unsigned int), 10);
+			goto string;
+		case 'x': // Unsigned hex int
+			s = pf_itoa(va_arg(args, unsigned int), 16);
+			goto string;
+		case 'f': // Float
+			s = pf_ftoa(va_arg(args, double));
+			goto string;
+		case 's': // String
+			s = va_arg(args, char*);
+		string: // Prints the string in s
+			if (s == NULL) s = "(null)";
+			while (*s != '\0' && i < len) buf[i++] = *s++;
+			break;
+		default: // Something else
+			if (i < len) buf[i++] = '%';
+			if (i < len) buf[i++] = *fmt;
+			break;
+		}
+
+		fmt++;
+	}
+
+	if (i < len) buf[i++] = '\0';
+
+	return i;
+}
+