refactor, new arch dirs, (wip) page alloc on write, hsv screen (convert to userspace later), other fixes

27 files changed, 320 insertions, 129 deletions

diff --git a/include/bochs.h b/include/bochs.h
new file mode 100644
index 0000000..4aa933e
--- /dev/null
+++ b/include/bochs.h
@@ -0,0 +1,11 @@
+#pragma once
+
+#include <stdint.h>
+#include <stdint.h>
+
+/**
+ * Loads the framebuffer
+ * @param width - the width of the screen
+ * @param height - the height of the screen
+ */
+uint32_t *bochs_init(uint16_t w, uint16_t h, uint8_t b);
diff --git a/include/fb.h b/include/fb.h
deleted file mode 100644
index 2c5ea13..0000000
--- a/include/fb.h
+++ /dev/null
@@ -1,5 +0,0 @@
-#pragma once
-
-#include <stdint.h>
-
-int fb_init(uint16_t res_x, uint16_t res_y);
diff --git a/include/screen.h b/include/screen.h
new file mode 100644
index 0000000..296be31
--- /dev/null
+++ b/include/screen.h
@@ -0,0 +1,13 @@
+#pragma once
+
+#include <shim.h>
+
+/**
+ * Initalizes the screen and framebuffer
+ */
+void screen_init(void);
+
+/**
+ * Redraws the screen
+ */
+void screen_redraw(void);
diff --git a/include/shim.h b/include/shim.h
index 498de92..e445765 100644
--- a/include/shim.h
+++ b/include/shim.h
@@ -15,16 +15,17 @@ struct memory_map {
 	struct memory_segment entries[MMAP_MAX_ENTRY];
 };
 
-//struct framebuffer {
-//	uint64_t addr;
-//	uint32_t pitch;
-//	uint32_t width;
-//	uint32_t height;
-//	uint8_t bit_depth;
-//};
+struct framebuffer {
+	uint64_t addr;
+	uint32_t pitch;
+	uint32_t width;
+	uint32_t height;
+	uint8_t bit_depth;
+};
 
 struct boot_info {
 	struct memory_map map;
+	struct framebuffer fb;
 	void *symbol_table;
 	void *acpi_table;
 	char cmdline[CMDLINE_MAX];
diff --git a/src/arch/amd64/acpi.c b/src/arch/amd64/acpi.c
index e262a99..eb38f73 100644
--- a/src/arch/amd64/acpi.c
+++ b/src/arch/amd64/acpi.c
@@ -1,14 +1,12 @@
 #include <acpi.h>
 #include <lib.h>
-
+#include <memory.h>
 #include <stdint.h>
 #include <stddef.h>
+#include <string.h>
+#include <panic.h>
 
 #include "bindings.h"
-#include "memory.h"
-
-/* global state, idk a better way rn */
-struct acpi_state state;
 
 struct acpi_header {
 	char signature[4];
@@ -20,7 +18,7 @@ struct acpi_header {
 	uint32_t oem_revision;
 	uint32_t creator_id;
 	uint32_t creator_revision;
-};
+} __attribute__((packed));
 
 // root system descriptor pointer
 // ACPI 1.0
@@ -30,7 +28,7 @@ struct rsdp {
 	char oemid[6];
 	uint8_t revision;
 	uint32_t rsdt_addr;
-};
+} __attribute__((packed));
 
 // eXtended system descriptor pointer
 // ACPI 2.0
@@ -45,7 +43,7 @@ struct xsdp {
 	uint64_t xsdt_addr;
 	uint8_t extendeid_checksum;
 	uint8_t reserved[3];
-};
+} __attribute__((packed));
 
 // root system descriptor table
 // ACPI 1.0
@@ -152,6 +150,9 @@ struct acpi_state {
 	uint16_t SCI_EN;
 };
 
+/* global state, idk a better way rn */
+static struct acpi_state state;
+
 static bool checksum(uint8_t *data, size_t len) {
 	unsigned char sum = 0;
 	for (size_t i = 0; i < len; i++)
@@ -230,6 +231,9 @@ static void *acpi_find_table_xsdt(struct xsdt *xsdt, const char *identifier, int
 }
 
 int acpi_init_rsdt(struct rsdt *rsdt) {
+
+	kprintf("RSDT: %#016lx\n", (size_t)rsdt);
+
 	rsdt = mmap(rsdt, sizeof(struct rsdt));
 
 	state.dst.rsdt = rsdt;
@@ -278,23 +282,35 @@ int acpi_init(void *rootsdp) {
 	if (!checksum((uint8_t *)rsdp, sizeof(struct rsdp)))
 		return -1;
 
+	if (strncmp(rsdp->signature, "RSD PTR ", 8) != 0) {
+		panic("invalid acpi rsdp signature: %.*s\n", 8, rsdp->signature);
+	}
+
 	int res;
 
 	if (rsdp->revision == 0) {
+		kprintf("ACPI 1.0\n");
+		kprintf("RSDP: %#016lx\n", (size_t)rsdp);
 		res = acpi_init_rsdt(
 				(struct rsdt *) (uintptr_t) rsdp->rsdt_addr
 		);
 	} else if (rsdp->revision == 2) {
 		struct xsdp *xsdp = (struct xsdp *) rsdp;
+		kprintf("ACPI 2.0\n");
+		kprintf("XSDP: %#016lx\n", (size_t)xsdp);
 		res = acpi_init_xsdt(
 				(struct xsdt *) (uintptr_t) xsdp->xsdt_addr
 		);
 	} else {
-		return -1;
+		panic("invalid acpi rev: %d\n", rsdp->revision);
 	}
 
-	if (res)
+	if (res) {
+		kprintf("...acpi failed to load\n\n");
 		return res;
+	}
+
+	kprintf("\n\n");
 
 	int ret = read_s5_addr(&state);
 	if (!ret)
diff --git a/src/arch/amd64/backtrace.c b/src/arch/amd64/cpu/backtrace.c
index 9e1c9d7..9e1c9d7 100644
--- a/src/arch/amd64/backtrace.c
+++ b/src/arch/amd64/cpu/backtrace.c
diff --git a/src/arch/amd64/debugger.c b/src/arch/amd64/cpu/debugger.c
index a1fa968..4d9d3c3 100644
--- a/src/arch/amd64/debugger.c
+++ b/src/arch/amd64/cpu/debugger.c
@@ -2,6 +2,7 @@
 #include <stddef.h>
 #include <backtrace.h>
 #include <serial.h>
+
 #include "debugger.h"
 
 struct dr6 {
@@ -195,8 +196,8 @@ static int debugger_handle_bkp_cmd(char *msg) {
 			const char *lenstrs[] = {"1", "2", "8", "4"};
 			const char *rwstrs[] = {"x ", "w ", "io", "rw"};
 			kprintf(
-				"breakpoint %d: %#016lx len=%s trigger=%s instrlen=%01d %s\n", 
-				i, 
+				"breakpoint %d: %#016lx len=%s trigger=%s instrlen=%01d %s\n",
+				i,
 				bkp.addr,
 				lenstrs[bkp.len],
 				rwstrs[bkp.rw],
diff --git a/src/arch/amd64/debugger.h b/src/arch/amd64/cpu/debugger.h
index e679c07..14f73bf 100644
--- a/src/arch/amd64/debugger.h
+++ b/src/arch/amd64/cpu/debugger.h
@@ -3,7 +3,7 @@
 #include "idt.h"
 
 #define DEBUG_INT3  0x00
-#define DEBUG_DBG   0x01 
+#define DEBUG_DBG   0x01
 #define DEBUG_FAULT 0x02
 
 void debugger(struct isr_regs *state, int cause);
diff --git a/src/arch/amd64/idt.S b/src/arch/amd64/cpu/idt.S
index cd8783e..cd8783e 100644
--- a/src/arch/amd64/idt.S
+++ b/src/arch/amd64/cpu/idt.S
diff --git a/src/arch/amd64/idt.c b/src/arch/amd64/cpu/idt.c
index d33c795..053f614 100644
--- a/src/arch/amd64/idt.c
+++ b/src/arch/amd64/cpu/idt.c
@@ -2,10 +2,10 @@
 #include <stddef.h>
 #include <lib.h>
 #include <panic.h>
-
-#include "debugger.h"
 #include "idt.h"
-#include "pic.h"
+#include "debugger.h"
+#include "../paging.h"
+#include "../drivers/pic.h"
 
 #define IDT_SIZE 256
 
@@ -148,7 +148,7 @@ void idt_pic_timer(void) {
 	// print a message once we know the timer works
 	// but avoid spamming the logs
 	if (counter == 3) {
-		kputs("pic timer!\n");
+		//kputs("pic timer!\n");
 	}
 	if (counter <= 3) {
 		counter++;
@@ -158,4 +158,3 @@ void idt_pic_timer(void) {
 void idt_pic_keyboard(void) {}
 
 void idt_pic_mouse(void) {}
-
diff --git a/src/arch/amd64/idt.h b/src/arch/amd64/cpu/idt.h
index 89a9dab..89a9dab 100644
--- a/src/arch/amd64/idt.h
+++ b/src/arch/amd64/cpu/idt.h
diff --git a/src/arch/amd64/fb.c b/src/arch/amd64/drivers/bochs.c
index 8560166..5383213 100644
--- a/src/arch/amd64/fb.c
+++ b/src/arch/amd64/drivers/bochs.c
@@ -3,8 +3,9 @@
 #include <stdint.h>
 #include <panic.h>
 #include <pci.h>
+#include <bochs.h>
 
-#include "bindings.h"
+#include "../bindings.h"
 
 #define INDEX           0x1CE
 #define DATA            0x1CF
@@ -52,38 +53,21 @@ static void set_mode(uint16_t width, uint16_t height, uint16_t bit_depth, int lf
         (clear ? 0 : DATA_NO_CLEAR_MEM));
 }
 
-//static void set_bank(uint16_t bank) {
-//    write(INDEX_BANK, bank);
-//}
+uint32_t* bochs_init(uint16_t width, uint16_t height, uint8_t bit_depth) {
 
-int fb_init(uint16_t width, uint16_t height) {
-
-	set_mode(width, height, 32, true, true);
+	set_mode(width, height, bit_depth, true, true);
 
 	if (!is_available())
-		panic("bochs framebuffer not avaliable");
+        return NULL;
 
     struct pci_device bochs = {0};
     bool found = pci_findby_id(&bochs, BOCHS_PCI_DEVICE, BOCHS_PCI_VENDOR, NULL);
     if (!found)
-        panic("bochs pci device not avaliable");
+        return NULL;
 
     uint32_t bar0 = pci_rcfg_d(bochs, PCI_BAR0_D);
-    uint32_t *fb = (uint32_t*) (uintptr_t) bar0;
-    fb = mmap(fb, width * height * 4);
-
-	for (uint16_t y = 0; y < height; y++) {
-		for (uint16_t x = 0; x < width; x++) {
-            double dx = x / (double) width,
-                   dy = y / (double) height,
-                   dz = (2 - dx - dy) / 2;
-            uint32_t r = (uint32_t)(dx * 255),
-                     g = (uint32_t)(dy * 255),
-                     b = (uint32_t)(dz * 255);
-			fb[x + y * width] = (b << 0) | (g << 8) | (r << 16);
-		}
-	}
-
+    uint32_t *addr = (uint32_t*) (uintptr_t) bar0;
+    addr = mmap(addr, width * height * bit_depth);
 
-    return 0;
+    return addr;
 }
diff --git a/src/arch/amd64/pci.c b/src/arch/amd64/drivers/pci.c
index 7b30f0e..410eb7e 100644
--- a/src/arch/amd64/pci.c
+++ b/src/arch/amd64/drivers/pci.c
@@ -3,7 +3,7 @@
 #include <panic.h>
 #include <lib.h>
 
-#include "bindings.h"
+#include "../bindings.h"
 
 #define CONF_ADDR 0xCF8
 #define CONF_DATA 0xCFC
diff --git a/src/arch/amd64/pic.c b/src/arch/amd64/drivers/pic.c
index c25856b..be7716f 100644
--- a/src/arch/amd64/pic.c
+++ b/src/arch/amd64/drivers/pic.c
@@ -1,4 +1,4 @@
-#include "bindings.h"
+#include "../bindings.h"
 #include "pic.h"
 
 #define PIC1            0x20        /* IO base address for master PIC */
diff --git a/src/arch/amd64/pic.h b/src/arch/amd64/drivers/pic.h
index 2a4670e..2a4670e 100644
--- a/src/arch/amd64/pic.h
+++ b/src/arch/amd64/drivers/pic.h
diff --git a/src/arch/amd64/serial.c b/src/arch/amd64/drivers/serial.c
index fe21629..b9e351e 100644
--- a/src/arch/amd64/serial.c
+++ b/src/arch/amd64/drivers/serial.c
@@ -1,5 +1,6 @@
 #include <serial.h>
-#include "bindings.h"
+
+#include "../bindings.h"
 
 #define PORT 0x3F8
 
diff --git a/src/arch/amd64/fpu.c b/src/arch/amd64/fpu.c
index 551485e..43fc653 100644
--- a/src/arch/amd64/fpu.c
+++ b/src/arch/amd64/fpu.c
@@ -1,6 +1,7 @@
 #include <fpu.h>
 #include <stddef.h>
 #include <stdint.h>
+#include <lib.h>
 
 void enable_fpu() {
 	size_t cr4;
diff --git a/src/arch/amd64/linker.ld b/src/arch/amd64/linker.ld
deleted file mode 100644
index 0032765..0000000
--- a/src/arch/amd64/linker.ld
+++ /dev/null
@@ -1,38 +0,0 @@
-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 315747e..34424a0 100644
--- a/src/arch/amd64/mboot.c
+++ b/src/arch/amd64/mboot.c
@@ -9,6 +9,7 @@
 
 #define MBOOT_CMDLINE       1
 #define MBOOT_MEMORY_MAP    6
+#define MBOOT_FRAMEBUFFER   8
 #define MBOOT_ELF_SYMBOLS   9
 #define MBOOT_OLD_RSDP     14
 #define MBOOT_NEW_RSDP     15
@@ -82,6 +83,18 @@ struct mboot_tag_cmdline {
 	uint8_t cmdline[];
 };
 
+struct mboot_tag_framebuffer {
+  uint32_t type;
+  uint32_t size;
+  uint64_t framebuffer_addr;
+  uint32_t framebuffer_pitch;
+  uint32_t framebuffer_width;
+  uint32_t framebuffer_height;
+  uint8_t framebuffer_bpp;
+  uint8_t framebuffer_type;
+  uint16_t reserved;
+};
+
 static void read_symbols(
 		struct boot_info *shim_info,
 		struct mboot_tag_elf_sections *sections
@@ -133,6 +146,17 @@ static void read_cmdline(
 	shim_info->cmdline[size] = '\0';
 }
 
+static void read_framebuffer(
+		struct boot_info *shim_info,
+		struct mboot_tag_framebuffer *framebuffer
+) {
+	shim_info->fb.addr = framebuffer->framebuffer_addr;
+	shim_info->fb.width = framebuffer->framebuffer_width;
+	shim_info->fb.height = framebuffer->framebuffer_height;
+	shim_info->fb.pitch = framebuffer->framebuffer_pitch;
+	shim_info->fb.bit_depth = framebuffer->framebuffer_bpp;
+}
+
 static const char *segment_type[] = {
 	"Reserved",
 	"Free",
@@ -217,6 +241,12 @@ void mboot_load_info(
 						(struct mboot_tag_cmdline *) tag
 				);
 				break;
+			case MBOOT_FRAMEBUFFER:
+				read_framebuffer(
+						shim_info,
+						(struct mboot_tag_framebuffer *) tag
+				);
+				break;
 			case MBOOT_MEMORY_MAP:
 				read_memory_map(
 						shim_info,
diff --git a/src/arch/amd64/paging.c b/src/arch/amd64/paging.c
index 604e0a0..1c1c56c 100644
--- a/src/arch/amd64/paging.c
+++ b/src/arch/amd64/paging.c
@@ -45,7 +45,8 @@ struct pde {
 // PAGE TABLE ENTRY
 struct pte {
 	uint64_t flags              : 9;
-	uint64_t                    : 3;
+	uint64_t loaded             : 1;
+	uint64_t                    : 2;
 	uint64_t address            : 40;
 	uint64_t                    : 7;
 	uint64_t protection_key     : 4;
@@ -69,7 +70,7 @@ static struct pde   *pd_mapped   = (void *) (uintptr_t) 0x202000;
 static struct pte   *pt_mapped   = (void *) (uintptr_t) 0x203000;
 
 static inline void invlpg(void *addr) {
-	__asm volatile("invlpg (%0)" ::"r" (addr) : "memory");
+	__asm__ volatile("invlpg (%0)" ::"r" (addr) : "memory");
 }
 
 static void load_addr(void *phys_addr) {
@@ -297,6 +298,7 @@ static void unmap_page(
 
 	page->address = 0;
 	page->flags = 0;
+	page->loaded = 0;
 
 	try_unmap_pt();
 
@@ -360,6 +362,7 @@ static void unmap_pages(
 
 		page->address = 0;
 		page->flags = 0;
+		page->loaded = 0;
 
 	}
 
@@ -369,6 +372,31 @@ static void unmap_pages(
 	return;
 }
 
+static struct pte *get_page(
+		struct pml4e *root,
+		void *virt
+) {
+	struct pdpte *pdpt;
+	struct pde   *pd;
+	struct pte   *pt;
+	struct pte   *page;
+
+	unsigned int df = 0;
+
+	if (select_pdpt(virt, df, root, &pdpt, false))
+		return NULL;
+
+	if (select_pd(virt, df, pdpt, &pd, false))
+		return NULL;
+
+	if (select_pt(virt, df, pd, &pt, false))
+		return NULL;
+
+	select_page(virt, pt, &page);
+
+	return page;
+}
+
 static int map_page(
 		struct pml4e *root,
 		void *virt,
@@ -382,6 +410,9 @@ static int map_page(
 
 	unsigned int df = F_WRITEABLE;
 
+	if (phys == NULL)
+		df = 0; // alloc page on fault
+
 	if (select_pdpt(virt, df, root, &pdpt, true))
 		return 1;
 
@@ -393,9 +424,16 @@ static int map_page(
 
 	select_page(virt, pt, &page);
 
-	page->address = (uint64_t)phys >> 12;
-	page->flags = F_PRESENT | flags;
-	invlpg(virt);
+	if (phys) {
+		page->flags = F_PRESENT | flags;
+		page->address = (uint64_t)phys >> 12;
+		page->loaded = 1;
+		invlpg(virt);
+	} else {
+		page->flags = flags;
+		page->address = 0;
+		page->loaded = 0;
+	}
 
 	return 0;
 }
@@ -424,6 +462,9 @@ static int map_pages(
 
 	unsigned int df = F_WRITEABLE;
 
+	if (phys_start == NULL)
+		df = 0; // alloc page on fault
+
 	long i;
 	for (i = 0; i < page_count; i++) {
 
@@ -454,15 +495,22 @@ static int map_pages(
 
 		select_page(virt, pt, &page);
 
-		page->address = (uint64_t)phys >> 12;
-		page->flags = F_PRESENT | flags;
+		if (phys_start) {
+			page->flags = F_PRESENT | flags;
+			page->address = (uint64_t)phys >> 12;
+			page->loaded = 1;
+		} else {
+			page->flags = flags;
+			page->address = 0;
+			page->loaded = 0;
+		}
 
 		if (flags & F_GLOBAL)
 			invlpg(virt);
 
 	}
 
-	__asm volatile("mov %cr3, %rax; mov %rax, %cr3;");
+	__asm__ volatile("mov %cr3, %rax; mov %rax, %cr3;");
 
 	return 0;
 
@@ -575,3 +623,21 @@ int kunmap_page(void *virt_addr) {
 	unmap_page(kernel_pml4, virt_addr);
 	return 0;
 }
+
+int kload_page(void *virt_addr) {
+	struct pte *page = get_page(kernel_pml4, virt_addr);
+	if (page == NULL)
+		return -1;
+	if (page->loaded)
+		return -1;
+	void *phys = alloc_phys_page();
+	kprintf("0x%p\n", phys);
+	if (phys == NULL)
+		return -2;
+	page->loaded = 1;
+	page->address = (uint64_t)phys >> 12;
+	page->flags |= F_PRESENT | F_WRITEABLE;
+	invlpg(virt_addr);
+	__asm__ volatile ("movq %cr3, %rax; movq %rax, %cr3;");
+	return 0;
+}
diff --git a/src/arch/amd64/paging.h b/src/arch/amd64/paging.h
index a76a172..9e1352c 100644
--- a/src/arch/amd64/paging.h
+++ b/src/arch/amd64/paging.h
@@ -13,3 +13,4 @@
 void paging_init(void);
 int kmap_page(void *virt_addr, void *phys_addr, unsigned int flags);
 int kunmap_page(void *virt_addr);
+int kload_page(void *virt_addr);
diff --git a/src/arch/amd64/shim.c b/src/arch/amd64/shim.c
index c161c88..b84167c 100644
--- a/src/arch/amd64/shim.c
+++ b/src/arch/amd64/shim.c
@@ -6,8 +6,8 @@
 
 #include "paging.h"
 #include "mboot.h"
-#include "idt.h"
-#include "pic.h"
+#include "cpu/idt.h"
+#include "drivers/pic.h"
 
 static struct boot_info boot_info;
 
diff --git a/src/kmain.c b/src/kmain.c
index 7ae9d01..249dd84 100644
--- a/src/kmain.c
+++ b/src/kmain.c
@@ -1,28 +1,27 @@
-#include "fpu.h"
+#include <fpu.h>
 #include <acpi.h>
 #include <memory.h>
 #include <lib.h>
-#include <fb.h>
+#include <serial.h>
 #include <shim.h>
 #include <panic.h>
 #include <pci.h>
+#include <screen.h>
 
 void kmain(struct boot_info *info) {
 	enable_fpu();
 	memory_init(&info->map);
 	pci_init();
-	fb_init(1024, 768);
-	//acpi_init(info->acpi_table);
+	screen_init();
+	acpi_init(info->acpi_table);
 
 	kprintf("enterd kmain\n");
 
-	*(char *)(0xB8000 + 0x144) = 'h';
-	*(char *)(0xB8000 + 0x146) = 'i';
+	char *test = kalloc(5);
+	*test = 1;
 
 
 	while (1) {
-		__asm__("hlt;");
-		// loop so we dont halt
-		// this allows interrupts to fire
+		screen_redraw();
 	}
 }
diff --git a/src/lib.c b/src/lib.c
index d2708c8..bd8e335 100644
--- a/src/lib.c
+++ b/src/lib.c
@@ -32,7 +32,9 @@ 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;
+	for (; n; n--) {
+		*d++ = c;
+	};
 	return dest;
 }
 
diff --git a/src/memory/memory.c b/src/memory/memory.c
index d1a163f..1e69d8a 100644
--- a/src/memory/memory.c
+++ b/src/memory/memory.c
@@ -51,7 +51,7 @@ void *kalloc_new(size_t size) {
 		node = 0;
 	}
 
-	memset(addr, 0, pages * PAGE_SIZE);
+	memcpy(addr, 0, pages * PAGE_SIZE);
 	struct page_header *header = addr;
     header->magic = 0xBEEFCAFE;
 	header->used = size;
diff --git a/src/print.c b/src/print.c
index 4adfcf7..fa16bab 100644
--- a/src/print.c
+++ b/src/print.c
@@ -138,6 +138,7 @@ static struct format_precision read_precision(const char *format, const char **e
 		if (c == '*' && precision.defined == false) {
 			precision.defined = true;
 			precision.varys = true;
+			format++;
 			break;
 		}
 
@@ -336,7 +337,7 @@ static void print_unum(
 	char buf[1024];
 	char *str = get_decimal(
 			num,
-			buf,
+			buf + 1023,
 			sign,
 			radix,
 			base
@@ -457,11 +458,21 @@ void kvprintf(const char *format, va_list args) {
 				char c;
 				const char *str;
 				void *ptr;
-			} data;
+			} data = {0};
 
 			int radix = 0;
 			char base = 0;
 
+			if (width.varys) {
+				int len = va_arg(args, int);
+				width.value = len;
+			}
+
+			if (precision.varys) {
+				int len = va_arg(args, int);
+				precision.value = len;
+			}
+
 			switch (conversion) {
 				case FMT_INT:
 					if (modifier == MOD_NONE)
@@ -475,7 +486,15 @@ void kvprintf(const char *format, va_list args) {
 					else if (modifier == MOD_LONG_LONG)
 						data.l = va_arg(args, long long);
 					radix = 10;
-					goto printnum;
+					print_num(
+							data.l,
+							flag,
+							width,
+							precision,
+							radix,
+							base
+					);
+					break;
 				case FMT_UINT:
 				case FMT_OCT:
 				case FMT_HEX_UPPER:
@@ -503,6 +522,7 @@ void kvprintf(const char *format, va_list args) {
 						base = 'A';
 					}
 					goto printunum;
+					break;
 				case FMT_PTR:
 				case FMT_PTR_UPPER:
 					flag |= FLG_ZERO;
@@ -513,15 +533,6 @@ void kvprintf(const char *format, va_list args) {
 					else
 						base = 'A';
 					goto printunum;
-				printnum:
-					print_num(
-							data.l,
-							flag,
-							width,
-							precision,
-							radix,
-							base
-					);
 					break;
 				printunum:
 					print_unum(
diff --git a/src/screen.c b/src/screen.c
new file mode 100644
index 0000000..6f682ae
--- /dev/null
+++ b/src/screen.c
@@ -0,0 +1,98 @@
+#include <lib.h>
+#include <screen.h>
+#include <bochs.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#define SCREEN_WIDTH	       1024
+#define SCREEN_HEIGHT          768
+#define SCREEN_BIT_DEPTH       32
+
+struct rgb {
+	uint8_t r;
+	uint8_t g;
+	uint8_t b;
+};
+
+struct hsv {
+	uint16_t h;
+	uint16_t s;
+	uint16_t v;
+};
+
+static uint32_t *buffer = NULL;
+static uint32_t width, height;
+static uint8_t bit_depth;
+
+static uint16_t angle;
+
+static void set_pixel(struct rgb color, uint16_t x, uint16_t y) {
+	uint32_t offset = y * width + x;
+	buffer[offset] = (color.b << 0) | (color.g << 8) | (color.r << 16);
+}
+
+static float fmod(float f, float m) {
+	return f - (int)(f / m) * m;
+}
+
+static float fabs(float f) {
+	return f > 0 ? f : -f;
+}
+
+static struct rgb htor(struct hsv hsv) {
+	struct rgb rgb;
+	float s = hsv.s / 100.0;
+	float v = hsv.v / 100.0;
+	float c = s * v;
+	float x = c * (1-fabs(fmod(hsv.h/60.0, 2) - 1));
+	float m = v - c;
+	float r,g,b;
+
+	if (hsv.h < 60) {
+		r = c; g = x; b = 0;
+	} else if (hsv.h >= 60 && hsv.h < 120) {
+		r = x; g = c; b = 0;
+	} else if (hsv.h >= 120 && hsv.h < 180) {
+		r = 0; g = c; b = x;
+	} else if (hsv.h >= 180 && hsv.h < 240) {
+		r = 0; g = x; b = c;
+	} else if (hsv.h >= 240 && hsv.h < 300) {
+		r = x; g = 0; b = c;
+	} else {
+		r = c; g = 0; b = x;
+	}
+
+	rgb.r = (r + m) * 255;
+	rgb.g = (g + m) * 255;
+	rgb.b = (b + m) * 255;
+
+	return rgb;
+}
+
+static struct rgb get_color(uint16_t a, uint16_t x, uint16_t y) {
+	struct hsv hsv = {
+		.h = a,
+		.s = x * 100.0 / width,
+		.v = y * 100.0 / height,
+	};
+	return htor(hsv);
+}
+
+void screen_init(void) {
+	angle = 0;
+	width = SCREEN_WIDTH;
+	height = SCREEN_HEIGHT;
+	bit_depth = SCREEN_BIT_DEPTH;
+	buffer = bochs_init(width, height, bit_depth);
+}
+
+void screen_redraw(void) {
+	for (uint16_t y = 0; y < height; y++) {
+		for (uint16_t x = 0; x < width; x++) {
+			struct rgb color = get_color(angle, x, height - y);
+			set_pixel(color, x, y);
+		}
+	}
+	angle++;
+	angle %= 360;
+}