acpi, fix mboot memory map, fix kalloc, fix virtalloc node allocator, add kprintf, other changes

17 files changed, 836 insertions, 137 deletions

diff --git a/Makefile b/Makefile
index 8b38f24..2a8c565 100644
--- a/Makefile
+++ b/Makefile
@@ -52,5 +52,7 @@ run: all
 	qemu-system-x86_64 \
 		-cdrom $(BUILD_DIR)/$(ISO_NAME) \
 		-serial stdio \
+		-display gtk,show-menubar=off,zoom-to-fit=on \
 		-m 4G \
+		-enable-kvm \
 		-name corn
diff --git a/include/lib.h b/include/lib.h
index 1b6d1f4..3be1f8b 100644
--- a/include/lib.h
+++ b/include/lib.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <stdarg.h>
 #include <stddef.h>
 
 /**
@@ -109,7 +110,7 @@ long long int atoll(const char* s);
 
 /**
  * Converts a integer to asci inside a string with a given radix (base).
- * @param n - the number to conver 
+ * @param n - the number to conver
  * @param buffer - the string buffer
  * @param radix - the base to convert
  */
@@ -117,15 +118,23 @@ char *itoa(int n, char *buffer, int radix);
 
 /**
  * Converts a long to asci inside a string with a given radix (base).
- * @param n - the number to conver 
+ * @param n - the number to conver
  * @param buffer - the string buffer
  * @param radix - the base to convert
  */
 char *ltoa(long int n, char *buffer, int radix);
 
 /**
+ * Converts a long long to asci inside a string with a given radix (base).
+ * @param n - the number to conver
+ * @param buffer - the string buffer
+ * @param radix - the base to convert
+ */
+char *lltoa(long long int n, char *buffer, int radix);
+
+/**
  * Converts a unsigned integer to asci inside a string with a given radix (base).
- * @param n - the number to conver 
+ * @param n - the number to conver
  * @param buffer - the string buffer
  * @param radix - the base to convert
  */
@@ -133,13 +142,21 @@ char *utoa(unsigned int n, char *buffer, int radix);
 
 /**
  * Converts a unsigned long to asci inside a string with a given radix (base).
- * @param n - the number to conver 
+ * @param n - the number to conver
  * @param buffer - the string buffer
  * @param radix - the base to convert
  */
 char *ultoa(unsigned long int n, char *buffer, int radix);
 
 /**
+ * Converts a unsigned long long to asci inside a string with a given radix (base).
+ * @param n - the number to conver
+ * @param buffer - the string buffer
+ * @param radix - the base to convert
+ */
+char *ulltoa(unsigned long long int n, char *buffer, int radix);
+
+/**
  * Converts the string in str to an int value based on the given base.
  * The endptr is updated to where the string was no longer valid.
  * @param str - the string buffer
@@ -168,3 +185,30 @@ long int strtol(const char *str, char **endptr, int base);
  * @returns 0 on error or success, error if endptr is still equal to str
  */
 long long int strtoll(const char *str, char **endptr, int base);
+
+/**
+ * Prints out a char
+ * @param c - the char
+ */
+void kputc(char c);
+
+/**
+ * Prints out a null terminated string
+ * @param s - the string
+ */
+void kputs(const char *s);
+
+/**
+ * Prints out a formatted string
+ * @param format - the format string
+ * @param ... - variable args for the format
+ */
+void kvprintf(const char *format, va_list args);
+
+/**
+ * Prints out a formatted string
+ * @param format - the format string
+ * @param ... - variable args for the format
+ */
+__attribute__((format(printf, 1, 2)))
+void kprintf(const char *format, ...);
diff --git a/include/serial.h b/include/serial.h
index a7da91c..7587d74 100644
--- a/include/serial.h
+++ b/include/serial.h
@@ -5,4 +5,4 @@
 int serial_init(void);
 uint8_t serial_in(void);
 void serial_out(uint8_t ch);
-void serial_out_str(char *str);
+void serial_out_str(const char *str);
diff --git a/include/shim.h b/include/shim.h
index dc8c19c..7178a0f 100644
--- a/include/shim.h
+++ b/include/shim.h
@@ -2,7 +2,8 @@
 
 #include <memory.h>
 
-#define CMDLINE_MAX 32
+#define CMDLINE_MAX     32
+#define MMAP_MAX_ENTRY  64
 
 struct memory_segment {
 	uint64_t addr;
@@ -12,8 +13,7 @@ struct memory_segment {
 
 struct memory_map {
 	uint32_t entry_count;
-	uint32_t entry_length;
-	struct memory_segment *entries;
+	struct memory_segment entries[MMAP_MAX_ENTRY];
 };
 
 struct boot_info {
diff --git a/src/arch/amd64/acpi.c b/src/arch/amd64/acpi.c
index 83f2014..70c2f38 100644
--- a/src/arch/amd64/acpi.c
+++ b/src/arch/amd64/acpi.c
@@ -31,7 +31,7 @@ struct rsdp {
 	char oemid[6];
 	uint8_t revision;
 	uint32_t rsdt_addr;
-} __attribute__((packed));
+};
 
 // eXtended system descriptor pointer
 // ACPI 2.0
@@ -46,7 +46,7 @@ struct xsdp {
 	uint64_t xsdt_addr;
 	uint8_t extendeid_checksum;
 	uint8_t reserved[3];
-} __attribute__((packed));
+};
 
 // root system descriptor table
 // ACPI 1.0
@@ -161,10 +161,8 @@ static bool checksum(uint8_t *data, size_t len) {
 }
 
 static int read_s5_addr(struct acpi_state *state) {
-	serial_out_str("a");
 	uintptr_t ptr = state->fadt.dsdt;
 	char *s5_addr = (void*) (ptr + 36);
-	serial_out_str("a");
 
 	int dsdt_len = *((int*) (ptr+1)) - 36;
 	while (0 < dsdt_len--) {
@@ -256,6 +254,7 @@ int acpi_init_rsdt(struct rsdt *rsdt) {
 int acpi_init_xsdt(struct xsdt *xsdt) {
 
 	xsdt = mmap(xsdt, sizeof(struct xsdt));
+	return -1;
 	state.dst.xsdt = xsdt;
 	state.version = 2;
 
diff --git a/src/arch/amd64/boot.S b/src/arch/amd64/boot.S
index 55d942b..455b68b 100644
--- a/src/arch/amd64/boot.S
+++ b/src/arch/amd64/boot.S
@@ -90,6 +90,8 @@ start:
 
 	push DWORD 0
 	push ebx
+	push DWORD 0
+	push eax
 
 	mov edi, 0x1000
 	mov cr3, edi
@@ -143,8 +145,10 @@ code64:
 	xor rbp, rbp          ; set ebp to 0 so we know where to end stack traces
 
 	pop rdi
+	pop rsi
 	call amd64_shim
 	mov rdi, rax
+	xor rsi, rsi
 
 	sti
 	call kmain
diff --git a/src/arch/amd64/linker.ld b/src/arch/amd64/linker.ld
new file mode 100644
index 0000000..0032765
--- /dev/null
+++ b/src/arch/amd64/linker.ld
@@ -0,0 +1,38 @@
+ENTRY(start)
+
+SECTIONS {
+    . = 1M;
+
+    kernel_start = .;
+
+    .boot BLOCK(4K) : ALIGN(4K)
+    {
+        *(.multiboot)
+    }
+
+    .rodata BLOCK(4K) : ALIGN(4K)
+    {
+        *(.rodata)
+    }
+
+    .data BLOCK(4K) : ALIGN(4K)
+    {
+        *(.data)
+    }
+
+    text_start = .;
+
+    .text BLOCK(4K) : ALIGN(4K)
+    {
+        *(.text)
+    }
+
+    text_end = .;
+
+    .bss BLOCK(4K) : ALIGN(4K)
+    {
+        *(.bss)
+    }
+
+    kernel_end = .;
+}
diff --git a/src/arch/amd64/mboot.c b/src/arch/amd64/mboot.c
index 6c3c413..b7124df 100644
--- a/src/arch/amd64/mboot.c
+++ b/src/arch/amd64/mboot.c
@@ -1,17 +1,25 @@
-#include "mboot.h"
-#include "serial.h"
-#include "shim.h"
-
+#include <shim.h>
 #include <lib.h>
 #include <stdint.h>
+#include <panic.h>
+
+#include "mboot.h"
+
+#define MBOOT_HEADER_MAGIC  0x36D76289
+
+#define MBOOT_CMDLINE       1
+#define MBOOT_MEMORY_MAP    6
+#define MBOOT_ELF_SYMBOLS   9
+#define MBOOT_OLD_RSDP     14
+#define MBOOT_NEW_RSDP     15
 
 extern char symtab;
 #define kaddr(addr) ((uintptr_t)(&addr))
 
-typedef unsigned char           mboot_uint8_t;
-typedef unsigned short          mboot_uint16_t;
-typedef unsigned int            mboot_uint32_t;
-typedef unsigned long long      mboot_uint64_t;
+typedef uint8_t   mboot_uint8_t;
+typedef uint16_t  mboot_uint16_t;
+typedef uint32_t  mboot_uint32_t;
+typedef uint64_t  mboot_uint64_t;
 
 struct mboot_info {
 	mboot_uint32_t total_size;
@@ -25,24 +33,17 @@ struct mboot_tag {
 	char data[];
 };
 
-enum mboot_tag_type {
-	MBOOT_CMDLINE = 0,
-	MBOOT_MEMORYMAP = 6,
-	MBOOT_SYMBOLS = 9,
-	MBOOT_RSDP = 14,
-	MBOOT_XSDP = 15,
-};
-
-struct mboot_elf_header_layout {
+struct mboot_tag_elf_sections {
 	mboot_uint32_t type;
 	mboot_uint32_t size;
-	mboot_uint32_t num;
-	mboot_uint32_t entsize;
-	mboot_uint32_t shndx;
-	char elf_section_headers[];
+	mboot_uint16_t num;
+	mboot_uint16_t entsize;
+	mboot_uint16_t shndx;
+	mboot_uint16_t reserved;
+	char sections[];
 };
 
-struct mboot_elf_section_header {
+struct mboot_tag_elf_sections_entry {
 	mboot_uint32_t sh_name;
 	mboot_uint32_t sh_type;
 	mboot_uint64_t sh_flags;
@@ -55,45 +56,46 @@ struct mboot_elf_section_header {
 	mboot_uint64_t sh_entsize;
 };
 
-struct mboot_memory_segment {
+struct mboot_mmap_entry {
 	mboot_uint64_t addr;
 	mboot_uint64_t len;
 	mboot_uint32_t type;
-	mboot_uint32_t reserved;
+	mboot_uint32_t zero;
 };
 
-struct mboot_memory_map {
-	mboot_uint32_t tag;
+struct mboot_tag_mmap {
+	mboot_uint32_t type;
 	mboot_uint32_t size;
 	mboot_uint32_t entry_size;
 	mboot_uint32_t entry_version;
-	struct memory_segment entries[];
+	struct mboot_mmap_entry entries[];
 };
 
-struct mboot_rsdp {
-	mboot_uint32_t tag;
+
+struct mboot_tag_old_rsdp {
+	mboot_uint32_t type;
 	mboot_uint32_t size;
 	mboot_uint8_t rsdp[];
 };
 
-struct mboot_xsdp {
-	mboot_uint32_t tag;
+struct mboot_tag_new_rsdp {
+	mboot_uint32_t type;
 	mboot_uint32_t size;
-	mboot_uint8_t xsdp[];
+	mboot_uint8_t rsdp[];
 };
 
-struct mboot_cmdline {
-	mboot_uint32_t tag;
+struct mboot_tag_cmdline {
+	mboot_uint32_t type;
 	mboot_uint32_t size;
-	char cmdline[];
+	mboot_uint8_t cmdline[];
 };
 
 static void read_symbols(
 		struct boot_info *shim_info,
-		struct mboot_elf_header_layout *layout
+		struct mboot_tag_elf_sections *sections
 ) {
 
-	shim_info->symbol_table = layout->elf_section_headers;
+	shim_info->symbol_table = sections->sections;
 
 //	struct mboot_elf_section_header *section =
 //		(struct mboot_elf_section_header *) (layout->elf_section_headers);
@@ -130,7 +132,7 @@ static void read_symbols(
 
 static void read_cmdline(
 		struct boot_info *shim_info,
-		struct mboot_cmdline *cmdline
+		struct mboot_tag_cmdline *cmdline
 ) {
 	mboot_uint32_t size = cmdline->size - 8;
 	if (size >= CMDLINE_MAX)
@@ -139,39 +141,49 @@ static void read_cmdline(
 	shim_info->cmdline[size] = '\0';
 }
 
-static void read_memorymap(
+static void read_memory_map(
 		struct boot_info *shim_info,
-		struct mboot_memory_map *map
+		struct mboot_tag_mmap *map
 ) {
-	int size = map->size - sizeof(mboot_uint32_t) * 4;
-	int count = size / map->entry_size;
-
-	shim_info->map.entry_count = count;
-	shim_info->map.entry_length = map->entry_size;
-	shim_info->map.entries = map->entries;
+	int idx = 0;
+	uintptr_t i = (uintptr_t)map->entries;
+	for (	;
+			i < (uintptr_t)map->entries + map->size;
+			i += map->entry_size, idx++
+	) {
+		struct mboot_mmap_entry *seg = (struct mboot_mmap_entry *) i;
+		shim_info->map.entries[idx].addr = seg->addr;
+		shim_info->map.entries[idx].type = seg->type;
+		shim_info->map.entries[idx].len = seg->len;
+	}
+	shim_info->map.entry_count = idx;
 }
 
-static void read_rsdp(
+static void read_old_rsdp(
 		struct boot_info *shim_info,
-		struct mboot_rsdp *rsdp
+		struct mboot_tag_old_rsdp *rsdp
 ) {
 	if (shim_info->acpi_table != NULL)
 		return; // xsdp is newer and has been loaded
 	shim_info->acpi_table = rsdp->rsdp;
 }
 
-static void read_xsdp(
+static void read_new_rsdp(
 		struct boot_info *shim_info,
-		struct mboot_xsdp *xsdp
+		struct mboot_tag_new_rsdp *rsdp
 ) {
-	shim_info->acpi_table = xsdp->xsdp;
+	shim_info->acpi_table = rsdp->rsdp;
 }
 
 void mboot_load_info(
+		long mboot_magic,
 		const void *mboot_data_ptr,
 		struct boot_info *shim_info
 ) {
 
+	if (mboot_magic != MBOOT_HEADER_MAGIC)
+		panic("invalid multiboot magic");
+
 	memset(shim_info, 0, sizeof(struct boot_info));
 
 	struct mboot_info *mboot_info = (struct mboot_info *) mboot_data_ptr;
@@ -186,31 +198,31 @@ void mboot_load_info(
 			case MBOOT_CMDLINE:
 				read_cmdline(
 						shim_info,
-						(struct mboot_cmdline *) tag
+						(struct mboot_tag_cmdline *) tag
 				);
 				break;
-			case MBOOT_MEMORYMAP:
-				read_memorymap(
+			case MBOOT_MEMORY_MAP:
+				read_memory_map(
 						shim_info,
-						(struct mboot_memory_map *) tag
+						(struct mboot_tag_mmap *) tag
 				);
 				break;
-			case MBOOT_SYMBOLS:
+			case MBOOT_ELF_SYMBOLS:
 				read_symbols(
 						shim_info,
-						(struct mboot_elf_header_layout *) tag
+						(struct mboot_tag_elf_sections *) tag
 				);
 				break;
-			case MBOOT_RSDP:
-				read_rsdp(
+			case MBOOT_OLD_RSDP:
+				read_old_rsdp(
 						shim_info,
-						(struct mboot_rsdp *) tag
+						(struct mboot_tag_old_rsdp *) tag
 				);
 				break;
-			case MBOOT_XSDP:
-				read_xsdp(
+			case MBOOT_NEW_RSDP:
+				read_new_rsdp(
 						shim_info,
-						(struct mboot_xsdp *) tag
+						(struct mboot_tag_new_rsdp *) tag
 				);
 				break;
 			default:
diff --git a/src/arch/amd64/mboot.h b/src/arch/amd64/mboot.h
index 90ed75c..b9c647b 100644
--- a/src/arch/amd64/mboot.h
+++ b/src/arch/amd64/mboot.h
@@ -8,4 +8,4 @@
  * @param mboot_info - the pointer passed from multiboot2
  * @param shim_info - the info to be collected by shim
  */
-void mboot_load_info(const void *mboot_info, struct boot_info *shim_info);
+void mboot_load_info(long mboot_magic, const void *mboot_info, struct boot_info *shim_info);
diff --git a/src/arch/amd64/serial.c b/src/arch/amd64/serial.c
index 85cd408..d63d9dd 100644
--- a/src/arch/amd64/serial.c
+++ b/src/arch/amd64/serial.c
@@ -16,7 +16,7 @@ int serial_init(void) {
 	// outb(port + 4, 0x0B); // TODO copied this from osdev wiki but i don't think you need it here
 	outb(PORT + 4, 0x1E); // set in loopback mode for test
 	outb(PORT + 0, 0xAE); // test by sending 0xAE
-	
+
 	uint8_t response = inb(PORT + 0);
 	if(response != 0xAE) {
 		// TODO panic here?
@@ -40,7 +40,7 @@ void serial_out(uint8_t ch) {
 	outb(PORT, ch);
 }
 
-void serial_out_str(char *str) {
+void serial_out_str(const char *str) {
 	for(; *str != '\0'; str++) {
 		serial_out(*str);
 	}
diff --git a/src/arch/amd64/shim.c b/src/arch/amd64/shim.c
index 7332994..3c0bd72 100644
--- a/src/arch/amd64/shim.c
+++ b/src/arch/amd64/shim.c
@@ -11,14 +11,13 @@
 
 static struct boot_info boot_info;
 
-void* amd64_shim(void *mboot_data_ptr) {
-
+void* amd64_shim(long mboot_magic, void *mboot_data_ptr) {
 	serial_init();
 	paging_init();
 	pic_remap();
 	idt_init();
 
-	mboot_load_info(mboot_data_ptr, &boot_info);
+	mboot_load_info(mboot_magic, mboot_data_ptr, &boot_info);
 
 	return &boot_info;
 }
diff --git a/src/kmain.c b/src/kmain.c
index 54ed506..057620d 100644
--- a/src/kmain.c
+++ b/src/kmain.c
@@ -10,11 +10,13 @@ void kmain(struct boot_info *info) {
 	//acpi_init(info->acpi_table);
 	//fb_init(1024, 768);
 
-	serial_out_str("entered kmain\n");
+	kprintf("enterd kmain\n");
+
 	*(char*)(0xB8000 + 0x144) = 'h';
 	*(char*)(0xB8000 + 0x146) = 'i';
 
 	while (1) {
+		//kprintf("ret: 0x%p\n", kalloc(2));
 		// loop so we dont halt
 		// this allows interrupts to fire
 	}
diff --git a/src/lib.c b/src/lib.c
index db09dda..7f3d79f 100644
--- a/src/lib.c
+++ b/src/lib.c
@@ -1,5 +1,5 @@
+#include "memory.h"
 #include <lib.h>
-
 #include <stddef.h>
 
 int memcmp(const void *restrict vl, const void *restrict vr, unsigned long n) {
@@ -31,6 +31,7 @@ void *memmove(void *dest, const void *src, unsigned long n) {
 }
 
 void *memset(void *restrict dest, int c, unsigned long n) {
+
 	unsigned char *d = dest;
 	for (; n; n--) *d++ = c;
 	return dest;
@@ -149,6 +150,7 @@ int ctoi(char c) {
 
 UXTOA(int, utoa)
 UXTOA(long int, ultoa)
+UXTOA(long long int, ulltoa)
 
 #define XTOA(type, name) \
 	char *name(type n, char* buffer, int radix) { \
@@ -176,6 +178,7 @@ UXTOA(long int, ultoa)
 
 XTOA(int, itoa)
 XTOA(long int, ltoa)
+XTOA(long long int, lltoa)
 
 #define STRTOX(name, type) \
 	type name(const char *s, char **endptr, int radix) { \
diff --git a/src/memory/memory.c b/src/memory/memory.c
index 1c69bae..af63865 100644
--- a/src/memory/memory.c
+++ b/src/memory/memory.c
@@ -1,10 +1,8 @@
+#include "serial.h"
 #include <memory.h>
 #include <stdint.h>
 #include <lib.h>
-
-#ifdef MEMORY_PANIC
 #include <panic.h>
-#endif
 
 #define MAGIC 0xBEEFCAFE
 
@@ -18,8 +16,8 @@ struct page_header {
 };
 
 static const size_t header_len = sizeof(struct page_header);
-struct page_header *start_header = NULL;
-struct page_header *end_header = NULL;
+static struct page_header *start_header = NULL;
+static struct page_header *end_header = NULL;
 
 struct page_header* get_header(void *ptr) {
 	struct page_header *header =
@@ -36,6 +34,7 @@ struct page_header* get_header(void *ptr) {
 
 void *kalloc_new(size_t size) {
 	size_t pages = ((size + header_len) / PAGE_SIZE) + 1;
+
 	void *addr = alloc_pages(pages);
 	void *mem = (char *)addr + header_len;
 
@@ -54,20 +53,20 @@ void *kalloc_new(size_t size) {
 	}
 
 	struct page_header *header = addr;
-	header->magic = MAGIC;
+    header->magic = 0xBEEFCAFE;
 	header->used = size;
 	header->free = free;
 	header->prev = end_header;
 	header->next = NULL;
 	header->node_number = node;
 
-	if (end_header == NULL) {
+	if (start_header == NULL) {
 		start_header = header;
-	} else {
-		end_header->next = header;
 	}
 
-	end_header = header;
+	if (end_header != NULL) {
+		end_header->next = header;
+	}
 
 	return mem;
 }
@@ -97,6 +96,9 @@ void *kalloc(size_t size) {
 
 	for (; header != NULL; header = header->next) {
 		size_t free = header->free;
+		if (free < header_len) {
+			continue;
+		}
 		if (size <= (free - header_len)) { // we must be able to fit data + header
 			break;
 		}
@@ -129,21 +131,13 @@ void *krealloc(void *src, size_t dst_len) {
 	header = get_header(src);
 
 	if (header == NULL) {
-#ifdef MEMORY_PANIC
 		panic("attempted to realloc on a invalid ptr");
-#else
-		return NULL; // invalid pointer passed
-#endif
 	}
 
 	src_len = header->used;
 
 	if (src_len == 0) {
-#ifdef MEMORY_PANIC
 		panic("attempted to realloc on an empty ptr");
-#else
-		return NULL; // likely double free :(
-#endif
 	}
 
 	dst = kalloc(dst_len);
@@ -166,11 +160,7 @@ void kfree(void *ptr) {
 	header = get_header(ptr);
 
 	if (header == NULL || header->used == 0) {
-#ifdef MEMORY_PANIC
 		panic("attempted to kfree invalid pointer");
-#else
-		return;
-#endif
 	}
 
 	header->free += header->used;
diff --git a/src/memory/physalloc.c b/src/memory/physalloc.c
index 1140258..bcbc66d 100644
--- a/src/memory/physalloc.c
+++ b/src/memory/physalloc.c
@@ -1,3 +1,4 @@
+#include "serial.h"
 #include <memory.h>
 #include <stdint.h>
 #include <lib.h>
@@ -63,6 +64,10 @@ static inline bool bitmap_get(int i) {
 }
 
 static inline void bitmap_set(int i, bool v) {
+	if (v)
+		free_memory -= PAGE_SIZE;
+	else
+		free_memory += PAGE_SIZE;
 	int idx = i / 64;
 	bitmap[idx] &= ~(1 << i % 64);
 	bitmap[idx] |=  (v << i % 64);
@@ -115,11 +120,11 @@ void free_phys_pages(void *ptr, int pages) {
 }
 
 static bool segment_invalid(const struct memory_segment *segment) {
-	if (segment->type != 1) return false;
-	if (segment->addr < kaddr(kernel_start)) return false;
-	if (segment->addr + segment->len < memory_start) return false;
-	if (segment->addr + segment->len < kaddr(kernel_start)) return false;
-	return true;
+	if (segment->type != 1) return true;
+	if (segment->addr < kaddr(kernel_start)) return true;
+	if (segment->addr + segment->len < memory_start) return true;
+	if (segment->addr + segment->len < kaddr(kernel_start)) return true;
+	return false;
 }
 
 static struct memory_area segment_to_area(const struct memory_segment *segment) {
@@ -195,18 +200,28 @@ void memory_init(struct memory_map *map) {
 
 	struct memory_area *area = page_start;
 
+	kprintf("MEMORY MAP\n");
 	for(uint32_t i = 0; i < map->entry_count; i++) {
 		struct memory_segment *segment = &map->entries[i];
 
 		if (segment_invalid(segment))
 			continue;
 
+		kprintf("addr: 0x%16p\tlen: %ld\n", (void *)segment->addr, segment->len);
+
 		struct memory_area temp = segment_to_area(segment);
 		*area = temp;
 		area++;
 	}
 
+	total_memory = page_count * PAGE_SIZE;
 	page_count -= bitmap_pages;
+	free_memory = page_count * PAGE_SIZE;
+
+	kprintf("\nMEMORY USAGE\n");
+	kprintf("mem total: %ld\n", memory_total());
+	kprintf("mem free:  %ld\n", memory_free());
+	kprintf("mem used:  %ld\n\n", memory_used());
 
 	memory_unlock();
 
diff --git a/src/memory/virtalloc.c b/src/memory/virtalloc.c
index 781fc9b..2ab9fc2 100644
--- a/src/memory/virtalloc.c
+++ b/src/memory/virtalloc.c
@@ -1,6 +1,9 @@
+#include "lib.h"
+#include "panic.h"
 #include <stdint.h>
 #include <stddef.h>
 #include <memory.h>
+#include <string.h>
 
 #define MEMORY_INTERNAL
 #include <memory/virtalloc.h>
@@ -10,34 +13,60 @@ struct addr_node {
 	uintptr_t end;
 	struct addr_node *next;
 	struct addr_node *prev;
-	uint8_t is_alloc;
-	uint8_t is_bss;
+	uint8_t is_alloc;        // if node is storing allocated data
+	uint8_t is_used;         // if node is in use by virtalloc
 };
 
-#define BOOTSTRAP_BSS_NODES 16
-static uint8_t bss_nodes = 0;
-static struct addr_node nodes[BOOTSTRAP_BSS_NODES];
+#define BSS_NODES 64
+static struct addr_node bootstrap_nodes[BSS_NODES];
+static struct addr_node *alloc_nodes = NULL;
+static size_t free_node_start = 0;
+static size_t alloc_node_count = 0;
+static size_t used_node_count = 0;
+static bool is_allocating = false;
 
-static struct addr_node *start_node;
+static struct addr_node *start_node = NULL;
 
-static struct addr_node *alloc_node(void) {
-	struct addr_node *node = NULL;
-	if (bss_nodes >= BOOTSTRAP_BSS_NODES) {
-		node = kalloc(sizeof(struct addr_node));
-		if (node == NULL)
-			return NULL;
-		node->is_bss = false;
+static struct addr_node *get_node_idx(int idx) {
+	if (idx < BSS_NODES) {
+		return &bootstrap_nodes[idx];
 	} else {
-		node = &nodes[bss_nodes];
-		bss_nodes += 1;
-		node->is_bss = true;
+		return &alloc_nodes[idx - BSS_NODES];
 	}
-	return node;
+}
+
+static struct addr_node *get_node(void) {
+	size_t count = BSS_NODES + alloc_node_count;
+
+	if (!is_allocating && used_node_count + 16 >= count) {
+		is_allocating = true;
+		int new_alloc = alloc_node_count * 2;
+		if (new_alloc < 8)
+			new_alloc = 8;
+		int allocated = new_alloc - alloc_node_count;
+		int old = new_alloc - allocated;
+		alloc_nodes = krealloc(alloc_nodes, sizeof(struct addr_node) * new_alloc);
+		memset(alloc_nodes + old, 0, sizeof(struct addr_node) + allocated);;
+		alloc_node_count = new_alloc;
+		is_allocating = false;
+		count = BSS_NODES + alloc_node_count;
+	}
+
+	size_t idx = free_node_start;
+	for (; idx < count; idx++) {
+		struct addr_node *node = get_node_idx(idx);
+		if (!node->is_used) {
+			used_node_count++;
+			return node;
+		}
+	}
+
+	panic("could not get virtaddr node");
 }
 
 static void free_node(struct addr_node *node) {
-	if (!node->is_bss)
-		kfree(node);
+	node->is_used = false;
+	used_node_count--;
 }
 
 void virtaddr_init(void) {
@@ -47,11 +76,11 @@ void virtaddr_init(void) {
 		.next = NULL,
 		.prev = NULL,
 		.is_alloc = false,
-		.is_bss = true,
+		.is_used = true,
 	};
-	nodes[0] = init;
-	start_node = &nodes[0];
-	bss_nodes++;
+	memset(bootstrap_nodes, 0, sizeof(bootstrap_nodes));
+	bootstrap_nodes[0] = init;
+	start_node = &bootstrap_nodes[0];
 }
 
 void *virtaddr_alloc(int n_pages) {
@@ -69,10 +98,7 @@ void *virtaddr_alloc(int n_pages) {
 
 		long length = node->end - node->start;
 		if (length >= n_length) {
-			struct addr_node *new = alloc_node();
-			if (node == NULL) {
-				return NULL;
-			}
+			struct addr_node *new = get_node();
 			if (node->prev != NULL) {
 				node->prev->next = new;
 			}
@@ -82,6 +108,7 @@ void *virtaddr_alloc(int n_pages) {
 			new->end = new->start + n_length;
 			node->start = new->end;
 			new->is_alloc = true;
+			new->is_used = true;
 			new->next = node;
 			return (void *) new->start;
 		}
diff --git a/src/print.c b/src/print.c
new file mode 100644
index 0000000..f158985
--- /dev/null
+++ b/src/print.c
@@ -0,0 +1,564 @@
+#include <lib.h>
+#include <serial.h>
+#include <stdarg.h>
+
+void kputc(char c) {
+	serial_out(c);
+}
+
+void kputs(const char *s) {
+	serial_out_str(s);
+}
+
+enum format_flag {
+	FLG_NONE = 0x00,
+	FLG_ALTERNATE = 0x01,
+	FLG_ZERO = 0x02,
+	FLG_LEFT_ALIGN = 0x04,
+	FLG_ADD_SIGN = 0x08
+};
+
+struct format_width {
+	bool defined;
+	bool varys;
+	int value;
+};
+
+struct format_precision {
+	bool defined;
+	bool varys;
+	int value;
+};
+
+enum format_modifier {
+	MOD_NONE,
+	MOD_INVALID,
+	MOD_HALF_HALF,
+	MOD_HALF,
+	MOD_LONG_LONG,
+	MOD_LONG,
+};
+
+enum format_conversion {
+	FMT_INT,
+	FMT_UINT,
+	FMT_OCT,
+	FMT_HEX,
+	FMT_HEX_UPPER,
+	FMT_CHAR,
+	FMT_STR,
+	FMT_PTR,
+	FMT_PTR_UPPER,
+	FMT_PERCENT,
+	FMT_INVALID
+};
+
+static enum format_flag read_flag(const char *format, const char **end) {
+
+	enum format_flag flag = FLG_NONE;
+
+	for (; *format != '\0'; format++) {
+		switch (*format) {
+			case '#':
+				flag |= FLG_ALTERNATE;
+				break;
+			case '0':
+				flag |= FLG_ZERO;
+				break;
+			case '-':
+				flag |= FLG_LEFT_ALIGN;
+				break;
+			case '+':
+				flag |= FLG_ADD_SIGN;
+				break;
+			default:
+				*end = format;
+				return flag;
+		}
+	}
+
+	*end = format;
+	return flag;
+}
+
+static struct format_width read_width(const char *format, const char **end) {
+
+	struct format_width width;
+	width.defined = false;
+	width.varys = false;
+	width.value = 0;
+
+	int value = 0;
+
+	for (; *format != '\0'; format++) {
+		char c = *format;
+
+		if (c == '*' && width.defined == false) {
+			width.defined = true;
+			width.varys = true;
+			break;
+		}
+
+		if (!isdigit(c))
+			break;
+
+		int i = c - '0';
+		value *= 10;
+		value += i;
+
+		width.value = value;
+		width.defined = true;
+		width.varys = false;
+	}
+
+	*end = format;
+	return width;
+
+}
+
+static struct format_precision read_precision(const char *format, const char **end) {
+
+	struct format_precision precision;
+	precision.varys = false;
+	precision.defined = false;
+	precision.value = 0;
+
+	if (*format != '.') {
+		*end = format;
+		return precision;
+	}
+
+	format++;
+
+	int value = 0;
+
+	for (; *format != '\0'; format++) {
+		char c = *format;
+
+		if (c == '*' && precision.defined == false) {
+			precision.defined = true;
+			precision.varys = true;
+			break;
+		}
+
+		if (!isdigit(c))
+			break;
+
+		int i = c - '0';
+		value *= 10;
+		value += i;
+
+		precision.value = value;
+		precision.defined = true;
+		precision.varys = false;
+	}
+
+	*end = format;
+	return precision;
+}
+
+static enum format_modifier read_modifier(const char *format, const char **end) {
+
+	enum format_modifier mod = MOD_NONE;
+
+	for (; *format != '\0'; format++) {
+		*end = format;
+		switch (*format) {
+			case 'l':
+				if (mod == MOD_NONE)
+					mod = MOD_LONG;
+				else if (mod == MOD_LONG)
+					return MOD_LONG_LONG;
+				else
+					return MOD_INVALID;
+				break;
+			case 'L':
+				if (mod == MOD_NONE)
+					return MOD_LONG_LONG;
+				else
+					return MOD_INVALID;
+				break;
+			case 'h':
+				if (mod == MOD_NONE)
+					mod = MOD_HALF;
+				else if (mod == MOD_HALF)
+					return MOD_HALF_HALF;
+				else
+					return MOD_INVALID;
+				break;
+			case 'H':
+				if (mod == MOD_NONE)
+					return MOD_HALF_HALF;
+				else
+					return MOD_INVALID;
+				break;
+			default:
+				return mod;
+		}
+	}
+
+	return MOD_INVALID;
+}
+
+static enum format_conversion read_conversion(const char *format, const char **end) {
+	*end = format + 1;
+	switch (*format) {
+		case 'd':
+		case 'i':
+			return FMT_INT;
+		case 'o':
+			return FMT_OCT;
+		case 'u':
+			return FMT_UINT;
+		case 'x':
+			return FMT_HEX;
+		case 'X':
+			return FMT_HEX_UPPER;
+		case 'c':
+			return FMT_CHAR;
+		case 's':
+			return FMT_STR;
+		case 'p':
+			return FMT_PTR;
+		case 'P':
+			return FMT_PTR_UPPER;
+		case '%':
+			return FMT_PERCENT;
+		default:
+			return FMT_INVALID;
+	}
+}
+
+static void print_string(
+		const char *str,
+		enum format_flag flag,
+		struct format_width width,
+		struct format_precision precision
+) {
+
+	size_t max_len = 0;
+	size_t min_len = 0;
+	size_t len = 0;
+
+	if (width.defined)
+		min_len = width.value;
+
+	if (precision.defined) {
+		max_len = precision.value;
+		len = max_len;
+		if (max_len < min_len)
+			min_len = max_len;
+	} else {
+		len = strlen(str);
+	}
+
+	if (!(flag & FLG_LEFT_ALIGN) && len < min_len) {
+		for (size_t i = 0; i < (min_len - len); i++) {
+			kputc(' ');
+		}
+	}
+
+	for (size_t i = 0; i < len; i++) {
+		kputc(str[i]);
+	}
+
+	if ((flag & FLG_LEFT_ALIGN) && len < min_len) {
+		for (size_t i = 0; i < (min_len - len); i++) {
+			kputc(' ');
+		}
+	}
+}
+
+static char get_letter(
+		char c,
+		char base
+) {
+	if (c >= 0 && c <= 9)
+		return c + '0';
+	c -= 10;
+	return c + base;
+}
+
+static char *get_decimal(
+		long long num,
+		char *buf,
+		char sign,
+		int radix,
+		char base
+) {
+
+	*buf = '\0';
+	buf--;
+
+	if (num == 0) {
+		*buf = '0';
+		buf--;
+	}
+
+	while (num != 0) {
+		char i = num % radix;
+		char c = get_letter(i, base);
+		*buf = c;
+		buf--;
+		num /= radix;
+	}
+
+	if (sign) {
+		*buf = sign;
+		buf--;
+	}
+
+	buf++;
+
+	return buf;
+}
+
+static void print_unum(
+		unsigned long long num,
+		enum format_flag flag,
+		struct format_width width,
+		struct format_precision precision,
+		bool isneg,
+		int radix,
+		char base
+) {
+
+	size_t max_len = 0;
+	size_t min_len = 0;
+	size_t len = 0;
+
+	char sign = 0;
+	if (isneg)
+		sign = '-';
+	else if (flag & FLG_ADD_SIGN)
+		sign = '+';
+
+	char buf[1024];
+	char *str = get_decimal(
+			num,
+			buf,
+			sign,
+			radix,
+			base
+	);
+
+	bool space_pre = (flag & FLG_LEFT_ALIGN) || !(flag & FLG_ZERO);
+
+	if (space_pre && radix == 16 && flag & FLG_ALTERNATE) {
+		char x = base + ('x' - 'a');
+		serial_out('0');
+		serial_out(x);
+	}
+
+	if (width.defined)
+		min_len = width.value;
+
+	if (precision.defined) {
+		max_len = precision.value;
+		len = max_len;
+		if (max_len < min_len)
+			min_len = max_len;
+	} else {
+		len = strlen(str);
+	}
+
+	bool zero_padded = false;
+
+	if (!(flag & FLG_LEFT_ALIGN) && len < min_len) {
+		for (size_t i = 0; i < (min_len - len); i++) {
+			(flag & FLG_ZERO) ? kputc('0') : kputc(' ');
+		}
+		if (flag & FLG_ZERO)
+			zero_padded = true;
+	}
+
+	kputs(str);
+
+	if (!zero_padded && (flag & FLG_ALTERNATE) && radix == 8)
+		kputc('0');
+
+	if ((flag & FLG_LEFT_ALIGN) && len < min_len) {
+		for (size_t i = 0; i < (min_len - len); i++) {
+			(flag & FLG_ZERO) ? kputc('0') : kputc(' ');
+		}
+	}
+}
+
+static void print_num(
+		long long num,
+		enum format_flag flag,
+		struct format_width width,
+		struct format_precision precision,
+		int radix,
+		char base
+) {
+	bool isneg = false;
+
+	if (num < 0) {
+		num = ~num;
+		isneg = true;
+	}
+
+	print_unum(
+			num,
+			flag,
+			width,
+			precision,
+			isneg,
+			radix,
+			base
+	);
+}
+
+void kvprintf(const char *format, va_list args) {
+	for (; *format != '\0'; format++) {
+		char c = *format;
+		if (c == '%') {
+			enum format_flag flag;
+			struct format_width width;
+			struct format_precision precision;
+			enum format_modifier modifier;
+			enum format_conversion conversion;
+
+			const char *ptr = format + 1;
+
+			flag = read_flag(ptr, &ptr);
+			width = read_width(ptr, &ptr);
+			precision = read_precision(ptr, &ptr);
+			modifier = read_modifier(ptr, &ptr);
+
+			if (modifier == MOD_INVALID) {
+				kputc('%');
+				continue;
+			}
+
+			conversion = read_conversion(ptr, &ptr);
+
+			if (conversion == FMT_INVALID) {
+				kputc('%');
+				continue;
+			}
+
+			union {
+				unsigned long long u;
+				long long l;
+				char c;
+				const char *str;
+				void *ptr;
+			} data;
+
+			int radix = 0;
+			char base = 0;
+
+			switch (conversion) {
+				case FMT_INT:
+					if (modifier == MOD_NONE)
+						data.l = va_arg(args, int);
+					else if (modifier == MOD_HALF)
+						data.l = (short) va_arg(args, int);
+					else if (modifier == MOD_HALF_HALF)
+						data.l = (char) va_arg(args, int);
+					else if (modifier == MOD_LONG)
+						data.l = va_arg(args, long);
+					else if (modifier == MOD_LONG_LONG)
+						data.l = va_arg(args, long long);
+					radix = 10;
+					goto printnum;
+				case FMT_UINT:
+				case FMT_OCT:
+				case FMT_HEX_UPPER:
+				case FMT_HEX:
+					if (modifier == MOD_NONE)
+						data.u = va_arg(args, unsigned int);
+					else if (modifier == MOD_HALF)
+						data.u = (unsigned short) va_arg(args, unsigned int);
+					else if (modifier == MOD_HALF_HALF)
+						data.u = (unsigned char) va_arg(args, unsigned int);
+					else if (modifier == MOD_LONG)
+						data.u = va_arg(args, unsigned long);
+					else if (modifier == MOD_LONG_LONG)
+						data.u = va_arg(args, unsigned long long);
+
+					if (conversion == FMT_UINT) {
+						radix = 10;
+					} else if (conversion == FMT_OCT) {
+						radix = 8;
+					} else if (conversion == FMT_HEX) {
+						radix = 16;
+						base = 'a';
+					} else if (conversion == FMT_HEX_UPPER) {
+						radix = 16;
+						base = 'A';
+					}
+					goto printunum;
+				case FMT_PTR:
+				case FMT_PTR_UPPER:
+					flag |= FLG_ZERO;
+					data.u = va_arg(args, size_t);
+					radix = 16;
+					if (conversion == FMT_PTR)
+						base = 'a';
+					else
+						base = 'A';
+					goto printunum;
+				printnum:
+					print_num(
+							data.l,
+							flag,
+							width,
+							precision,
+							radix,
+							base
+					);
+					break;
+				printunum:
+					print_unum(
+							data.u,
+							flag,
+							width,
+							precision,
+							false,
+							radix,
+							base
+					);
+					break;
+				case FMT_CHAR: {
+					char buf[2];
+					buf[0] = (char) va_arg(args, int);
+					buf[1] = '\0';
+					print_string(
+							buf,
+							flag,
+							width,
+							precision
+					);
+					break;
+				}
+				case FMT_STR:
+					data.str = va_arg(args, const char*);
+					print_string(
+							data.str,
+							flag,
+							width,
+							precision
+					);
+					break;
+				case FMT_PERCENT:
+					kputc('%');
+					break;
+				case FMT_INVALID:
+					break;
+			}
+			format = ptr - 1;
+		} else {
+			kputc(c);
+		}
+	}
+}
+
+void kprintf(const char *format, ...) {
+	va_list args;
+	va_start(args, format);
+	kvprintf(format, args);
+	va_end(args);
+}