diff --git a/Makefile b/Makefile
index 0e0cd75..c7a9046 100644
--- a/Makefile
+++ b/Makefile
@@ -16,7 +16,7 @@ export O?=$(abspath build)
 include conf/make/none.mk
 include conf/make/$(ARCH).mk
 
-all: mkdirs _doc $(TARGETS)
+all: mkdirs $(TARGETS)
 
 clean:
 	@rm -rf $(O)
diff --git a/conf/make/amd64.mk b/conf/make/amd64.mk
index 7698578..77f0119 100644
--- a/conf/make/amd64.mk
+++ b/conf/make/amd64.mk
@@ -1,15 +1,31 @@
 all:
 ### Kernel build
-OBJS+=$(O)/arch/amd64/entry.o
+DEFINES+=-DARCH_AMD64
+OBJS+=$(O)/arch/amd64/kernel.o \
+	  $(O)/arch/amd64/mm/pool.o \
+	  $(O)/arch/amd64/mm/mm.o \
+	  $(O)/arch/amd64/hw/rs232.o \
+	  $(O)/arch/amd64/hw/gdt.o \
+	  $(O)/arch/amd64/hw/gdt_s.o
+kernel_OBJS=$(O)/arch/amd64/entry.o \
+			$(OBJS)
 kernel_LINKER=$(S)/arch/amd64/link.ld
 kernel_LDFLAGS=-nostdlib -T$(kernel_LINKER)
-kernel_CFLAGS=-ffreestanding -I$(S)
+kernel_CFLAGS=-ffreestanding -I$(S) $(DEFINES) $(CFLAGS)
+DIRS+=$(O)/arch/amd64/mm \
+	  $(O)/arch/amd64/hw
 
-$(O)/kernel.elf: $(OBJS) $(kernel_LINKER)
-	$(CROSSLD) $(kernel_LDFLAGS)  -o $@ $(OBJS)
+$(O)/kernel.elf: $(kernel_OBJS) $(kernel_LINKER)
+	@printf " LD\t%s\n" $@
+	@$(CROSSLD) $(kernel_LDFLAGS)  -o $@ $(kernel_OBJS)
 
-$(O)/arch/amd64/%.o: $(S)/arch/amd64/%.S
-	$(CROSSCC) $(kernel_CFLAGS) -c -o $@ $<
+$(O)/%.o: $(S)/%.S
+	@printf " AS\t%s\n" $@
+	@$(CROSSCC) $(kernel_CFLAGS) -c -o $@ $<
+
+$(O)/%.o: $(S)/%.c
+	@printf " CC\t%s\n" $@
+	@$(CROSSCC) $(kernel_CFLAGS) -c -o $@ $<
 
 ### Kernel loader build
 TARGETS+=$(O)/loader.elf $(O)/kernel.elf
diff --git a/conf/make/none.mk b/conf/make/none.mk
index b27d7a0..70a8388 100644
--- a/conf/make/none.mk
+++ b/conf/make/none.mk
@@ -1,3 +1,11 @@
 HEADERS=$(shell find $(S) -name "*.h")
 
-OBJS+=
+CFLAGS+=-Wall \
+		-Wextra \
+		-Werror \
+		-Wno-unused-parameter
+
+DIRS+=$(O)/sys
+OBJS+=$(O)/sys/mem.o \
+	  $(O)/sys/string.o \
+	  $(O)/sys/debug.o
diff --git a/src/arch/amd64/entry.S b/src/arch/amd64/entry.S
index d11e6fd..93beb2c 100644
--- a/src/arch/amd64/entry.S
+++ b/src/arch/amd64/entry.S
@@ -1,5 +1,17 @@
 .section .text
 .global _start
 _start:
+    cli
+    movabsq $kernel_stack_top, %rsp
+
+    call kernel_main
+
 1:
+    cli
+    hlt
     jmp 1b
+
+.section .bss
+kernel_stack_bottom:
+    .skip 65536
+kernel_stack_top:
diff --git a/src/arch/amd64/hw/gdt.c b/src/arch/amd64/hw/gdt.c
new file mode 100644
index 0000000..625c175
--- /dev/null
+++ b/src/arch/amd64/hw/gdt.c
@@ -0,0 +1,44 @@
+#include "gdt.h"
+
+extern void amd64_reload_segs(void);
+
+#define AMD64_GDT_SIZE  3
+
+#define GDT_ACC_AC      (1 << 0)
+#define GDT_ACC_RW      (1 << 1)
+#define GDT_ACC_DC      (1 << 2)
+#define GDT_ACC_EX      (1 << 3)
+#define GDT_ACC_S       (1 << 4)
+#define GDT_ACC_R0      (0 << 5)
+#define GDT_ACC_R1      (1 << 5)
+#define GDT_ACC_R2      (2 << 5)
+#define GDT_ACC_R3      (3 << 5)
+#define GDT_ACC_PR      (1 << 7)
+
+#define GDT_FLG_LONG    (1 << 5)
+#define GDT_FLG_SZ      (1 << 6)
+#define GDT_FLG_GR      (1 << 7)
+
+static amd64_gdt_entry_t gdt[AMD64_GDT_SIZE];
+static amd64_gdt_ptr_t gdtr;
+
+static void amd64_gdt_set(int idx, uint32_t base, uint32_t limit, uint8_t flags, uint8_t access) {
+    gdt[idx].base_lo = base & 0xFFFF;
+    gdt[idx].base_mi = (base >> 16) & 0xFF;
+    gdt[idx].base_hi = (base >> 24) & 0xFF;
+    gdt[idx].access = access;
+    gdt[idx].flags = (flags & 0xF0) | ((limit >> 16) & 0xF);
+    gdt[idx].limit_lo = limit & 0xFFFF;
+}
+
+void amd64_gdt_init(void) {
+    gdtr.size = sizeof(gdt) - 1;
+    gdtr.offset = (uintptr_t) gdt;
+
+    amd64_gdt_set(0, 0, 0, 0, 0);
+    amd64_gdt_set(1, 0, 0, GDT_FLG_LONG, GDT_ACC_PR | GDT_ACC_R0 | GDT_ACC_EX | GDT_ACC_S | GDT_ACC_RW);
+    amd64_gdt_set(2, 0, 0, 0, GDT_ACC_PR | GDT_ACC_R0 | GDT_ACC_S | GDT_ACC_RW);
+
+    asm volatile ("lea gdtr(%rip), %rax; lgdt (%rax)");
+    amd64_reload_segs();
+}
diff --git a/src/arch/amd64/hw/gdt.h b/src/arch/amd64/hw/gdt.h
new file mode 100644
index 0000000..d1913ed
--- /dev/null
+++ b/src/arch/amd64/hw/gdt.h
@@ -0,0 +1,19 @@
+#pragma once
+#include <stdint.h>
+#include <stddef.h>
+
+typedef struct {
+    uint16_t limit_lo;
+    uint16_t base_lo;
+    uint8_t base_mi;
+    uint8_t access;
+    uint8_t flags;
+    uint8_t base_hi;
+} amd64_gdt_entry_t;
+
+typedef struct {
+    uint16_t size;
+    uintptr_t offset;
+} __attribute__((packed)) amd64_gdt_ptr_t;
+
+void amd64_gdt_init(void);
diff --git a/src/arch/amd64/hw/gdt_s.S b/src/arch/amd64/hw/gdt_s.S
new file mode 100644
index 0000000..ddafcef
--- /dev/null
+++ b/src/arch/amd64/hw/gdt_s.S
@@ -0,0 +1,21 @@
+.section .text
+.global amd64_reload_segs
+amd64_reload_segs:
+    cli
+
+    movabsq $.jmpbuf, %rax
+    rex.w ljmp *(%rax)
+
+.reload_data:
+    mov $0x10, %ax
+    mov %ax, %ds
+    mov %ax, %es
+    mov %ax, %fs
+    mov %ax, %gs
+    mov %ax, %ss
+
+    ret
+
+.jmpbuf:
+    .quad .reload_data
+    .word 0x08
diff --git a/src/arch/amd64/hw/io.h b/src/arch/amd64/hw/io.h
new file mode 100644
index 0000000..a9d6c04
--- /dev/null
+++ b/src/arch/amd64/hw/io.h
@@ -0,0 +1,28 @@
+#pragma once
+#include <stdint.h>
+
+static inline void outb(uint16_t addr, uint8_t v) {
+    asm volatile("outb %0, %1"::"a"(v), "Nd"(addr));
+}
+
+static inline uint8_t inb(uint16_t addr) {
+	uint8_t v;
+    asm volatile("inb %1, %0":"=a"(v):"Nd"(addr));
+	return v;
+}
+
+static inline void outl(uint16_t addr, uint32_t v) {
+    asm volatile("outl %0, %1"::"a"(v), "Nd"(addr));
+}
+
+static inline uint32_t inl(uint16_t addr) {
+	uint32_t v;
+    asm volatile("inl %1, %0":"=a"(v):"Nd"(addr));
+	return v;
+}
+
+static inline void io_wait(void) {
+    asm volatile("jmp 1f\n\t"
+                 "1:jmp 2f\n\t"
+                 "2:" );
+}
diff --git a/src/arch/amd64/hw/rs232.c b/src/arch/amd64/hw/rs232.c
new file mode 100644
index 0000000..c929e25
--- /dev/null
+++ b/src/arch/amd64/hw/rs232.c
@@ -0,0 +1,11 @@
+#include "rs232.h"
+#include "io.h"
+
+void rs232_init(uint16_t port) {
+    // Do nothing yet
+}
+
+void rs232_send(uint16_t port, char v) {
+    while (!(inb(port + 5) & 0x20)) {}
+	outb(port, v);
+}
diff --git a/src/arch/amd64/hw/rs232.h b/src/arch/amd64/hw/rs232.h
new file mode 100644
index 0000000..2b1591d
--- /dev/null
+++ b/src/arch/amd64/hw/rs232.h
@@ -0,0 +1,8 @@
+#pragma once
+#include <stdint.h>
+
+#define RS232_COM0  0x3F8
+
+void rs232_init(uint16_t port);
+void rs232_send(uint16_t port, char c);
+char rs232_recv(uint16_t port);
diff --git a/src/arch/amd64/kernel.c b/src/arch/amd64/kernel.c
new file mode 100644
index 0000000..7e0277a
--- /dev/null
+++ b/src/arch/amd64/kernel.c
@@ -0,0 +1,11 @@
+#include "sys/mm.h"
+#include "sys/debug.h"
+#include "arch/amd64/hw/gdt.h"
+
+void kernel_main(void) {
+    kdebug("Booting\n");
+
+    // Memory management
+    amd64_mm_init();
+    amd64_gdt_init();
+}
diff --git a/src/arch/amd64/link.ld b/src/arch/amd64/link.ld
index 1fa910b..de45f25 100644
--- a/src/arch/amd64/link.ld
+++ b/src/arch/amd64/link.ld
@@ -25,6 +25,7 @@ SECTIONS {
 	.data ALIGN(4K) : AT(ADDR(.data) - _kernel_base)
 	{
 		*(.data)
+        *(.data.rel.local)
 	}
 
 	.bss ALIGN(4K) : AT(ADDR(.bss) - _kernel_base)
diff --git a/src/arch/amd64/mm.h b/src/arch/amd64/mm.h
index 551d99c..531d318 100644
--- a/src/arch/amd64/mm.h
+++ b/src/arch/amd64/mm.h
@@ -3,6 +3,10 @@
 /// The place where the kernel pages are virtually mapped to
 #define KERNEL_VIRT_BASE        0xFFFFFF0000000000
 
+/// amd64 standard states that addresses' upper bits are copies of the 47th bit, so these need to be
+///  stripped down to only 48 bits
+#define AMD64_MM_MASK(a)        ((uintptr_t) (a) & 0xFFFFFFFFFFFF)
+
 /// Page map level 4
 typedef uint64_t *mm_pml4_t;
 /// Page directory pointer table
@@ -14,3 +18,5 @@ typedef uint64_t *mm_pagetab_t;
 
 /// Virtual memory space
 typedef mm_pml4_t mm_space_t;
+
+void amd64_mm_init(void);
diff --git a/src/arch/amd64/mm/mm.c b/src/arch/amd64/mm/mm.c
new file mode 100644
index 0000000..e956643
--- /dev/null
+++ b/src/arch/amd64/mm/mm.c
@@ -0,0 +1,28 @@
+#include "sys/mem.h"
+#include "sys/debug.h"
+#include "sys/mm.h"
+
+mm_space_t mm_kernel;
+
+void amd64_mm_init(void) {
+    kdebug("Memory manager init\n");
+
+    // Physical memory at this point:
+    //  0x000000 - 0x400000 - Used by kernel and info passed from the loader
+    // Virtual memory:
+    //  Lower 1GiB mapped to itself for loader access
+    //  0xFFFFFF0000000000 (1GiB) is mapped to 0 for kernel access
+
+    // XXX: assuming nothing important is there
+    uint64_t *pml4 = (uint64_t *) (0x200000 - 0x1000);
+    uint64_t *pdpt = (uint64_t *) (0x200000 - 0x2000);
+
+    memset((void *) (0x200000 - 2 * 0x1000), 0, 0x1000 * 2);
+
+    // 0xFFFFFF0000000000 -> 0 (1GiB) mapping
+    pml4[AMD64_MM_MASK(KERNEL_VIRT_BASE) >> 39] = (uint64_t) pdpt | 1 | 2;
+    pdpt[(AMD64_MM_MASK(KERNEL_VIRT_BASE) >> 30) & 0x1FF] = 1 | 2 | (1 << 7);
+
+    // Load the new table
+    asm volatile ("mov %0, %%cr3"::"a"(pml4):"memory");
+}
diff --git a/src/arch/amd64/mm/pool.c b/src/arch/amd64/mm/pool.c
new file mode 100644
index 0000000..68c4239
--- /dev/null
+++ b/src/arch/amd64/mm/pool.c
@@ -0,0 +1,14 @@
+#include "pool.h"
+#include "sys/mem.h"
+
+static struct {
+    uint64_t track[512];
+    uintptr_t start;
+    size_t size;
+} amd64_mm_pool;
+
+void amd64_mm_pool_init(uintptr_t begin, size_t size) {
+    amd64_mm_pool.start = begin;
+    amd64_mm_pool.size = size;
+    memset(amd64_mm_pool.track, 0, 512 * sizeof(uint64_t));
+}
diff --git a/src/arch/amd64/mm/pool.h b/src/arch/amd64/mm/pool.h
new file mode 100644
index 0000000..9108072
--- /dev/null
+++ b/src/arch/amd64/mm/pool.h
@@ -0,0 +1,12 @@
+#pragma once
+#include <stddef.h>
+#include <stdint.h>
+
+/// Initialize the paging structure allocation pool
+void amd64_mm_pool_init(uintptr_t base, size_t size);
+
+/// Allocate a paging structure
+uint64_t *amd64_mm_pool_alloc(void);
+
+/// Free a paging structure
+void amd64_mm_pool_free(uint64_t *obj);
diff --git a/src/sys/attr.h b/src/sys/attr.h
new file mode 100644
index 0000000..d0ba21d
--- /dev/null
+++ b/src/sys/attr.h
@@ -0,0 +1,3 @@
+#pragma once
+
+#define __weak __attribute__((weak))
diff --git a/src/sys/debug.c b/src/sys/debug.c
new file mode 100644
index 0000000..298c8b2
--- /dev/null
+++ b/src/sys/debug.c
@@ -0,0 +1,254 @@
+#include "debug.h"
+#include "string.h"
+#include <stdint.h>
+#include "sys/attr.h"
+
+#if defined(ARCH_AMD64)
+#include "arch/amd64/hw/rs232.h"
+#endif
+
+static const char *s_debug_xs_set0 = "0123456789abcdef";
+static const char *s_debug_xs_set1 = "0123456789ABCDEF";
+
+// TODO: make debugc a __weak function of a character
+void debugc(int level, char c) {
+#if defined(ARCH_AMD64)
+    rs232_send(RS232_COM0, c);
+#endif
+}
+
+void debugs(int level, const char *s) {
+    char c;
+    while ((c = *(s++))) {
+        debugc(level, c);
+    }
+}
+
+static void debugspl(int level, const char *s, char p, size_t c) {
+    size_t l = strlen(s);
+    for (size_t i = l; i < c; ++i) {
+        debugc(level, p);
+    }
+    debugs(level, s);
+}
+
+static void debugspr(int level, const char *s, char p, size_t c) {
+    size_t l = strlen(s);
+    debugs(level, s);
+    for (size_t i = l; i < c; ++i) {
+        debugc(level, p);
+    }
+}
+
+static void debugsp(int level, const char *s, char padc, int padl) {
+    if (padl > 0) {
+        debugspl(level, s, padc, padl);
+    } else {
+        debugspr(level, s, padc, -padl);
+    }
+}
+
+void debug_ds(int64_t x, char *res, int s, int sz) {
+    if (!x) {
+        res[0] = '0';
+        res[1] = 0;
+        return;
+    }
+
+    int c;
+    uint64_t v;
+
+    if (sz) {
+        if (s && x < 0) {
+            v = (uint64_t) -x;
+        } else {
+            s = 0;
+            v = (uint64_t) x;
+        }
+    } else {
+        if (s && ((int32_t) x) < 0) {
+            v = (uint64_t) -((int32_t) x);
+        } else {
+            s = 0;
+            v = (uint64_t) x;
+        }
+    }
+
+    c = 0;
+
+    while (v) {
+        res[c++] = '0' + v % 10;
+        v /= 10;
+    }
+
+    if (s) {
+        res[c++] = '-';
+    }
+
+    res[c] = 0;
+
+    for (int i = 0, j = c - 1; i < j; ++i, --j) {
+        res[i] ^= res[j];
+        res[j] ^= res[i];
+        res[i] ^= res[j];
+    }
+}
+
+void debug_xs(uint64_t v, char *res, const char *set) {
+    if (!v) {
+        res[0] = '0';
+        res[1] = 0;
+        return;
+    }
+
+    int c = 0;
+
+    while (v) {
+        res[c++] = set[v & 0xF];
+        v >>= 4;
+    }
+
+    res[c] = 0;
+
+    for (int i = 0, j = c - 1; i < j; ++i, --j) {
+        res[i] ^= res[j];
+        res[j] ^= res[i];
+        res[i] ^= res[j];
+    }
+}
+
+void debugf(int level, const char *f, ...) {
+    va_list args;
+    va_start(args, f);
+    debugfv(level, f, args);
+    va_end(args);
+}
+
+void debugfv(int level, const char *fmt, va_list args) {
+    char c;
+    union {
+        const char *v_string;
+        char v_char;
+        int32_t v_int32;
+        uint32_t v_uint32;
+        int64_t v_int64;
+        uint64_t v_uint64;
+        uintptr_t v_ptr;
+    } value;
+    char buf[64];
+    char padc;
+    int padn;
+    int padd;
+
+    while ((c = *fmt)) {
+        switch (c) {
+            case '%':
+                c = *(++fmt);
+
+                padc = ' ';
+                padd = 1;
+                padn = 0;
+                if (c == '0') {
+                    padc = c;
+                }
+
+                if (c == '-') {
+                    padd = -1;
+                    c = *(++fmt);
+                }
+
+                while (c >= '0' && c <= '9') {
+                    padn *= 10;
+                    padn += padd * (int) (c - '0');
+                    c = *(++fmt);
+                }
+
+                switch (c) {
+                    case 'l':
+                        c = *(++fmt);
+                        switch (c) {
+                            case 'd':
+                                value.v_int64 = va_arg(args, int64_t);
+                                debug_ds(value.v_int64, buf, 1, 1);
+                                debugsp(level, buf, padc, padn);
+                                break;
+                            case 'u':
+                                value.v_uint64 = va_arg(args, uint64_t);
+                                debug_ds(value.v_uint64, buf, 0, 1);
+                                debugsp(level, buf, padc, padn);
+                                break;
+                            case 'x':
+                                value.v_uint64 = va_arg(args, uint64_t);
+                                debug_xs(value.v_uint64, buf, s_debug_xs_set0);
+                                debugsp(level, buf, padc, padn);
+                                break;
+                            case 'X':
+                                value.v_uint64 = va_arg(args, uint64_t);
+                                debug_xs(value.v_uint64, buf, s_debug_xs_set1);
+                                debugsp(level, buf, padc, padn);
+                                break;
+                            case 'p':
+                                value.v_uint64 = va_arg(args, uint64_t);
+                                debugc(level, '0');
+                                debugc(level, 'x');
+                                debug_xs(value.v_uint64, buf, s_debug_xs_set0);
+                                debugspl(level, buf, '0', sizeof(uint64_t) * 2);
+                                break;
+                            default:
+                                debugc(level, '%');
+                                debugc(level, 'l');
+                                debugc(level, c);
+                                break;
+                        }
+                        break;
+                    case 'c':
+                        // char is promoted to int
+                        value.v_char = va_arg(args, int);
+                        debugc(level, value.v_char);
+                        break;
+                    case 'd':
+                        value.v_int64 = va_arg(args, int32_t);
+                        debug_ds(value.v_int64 & 0xFFFFFFFF, buf, 1, 0);
+                        debugsp(level, buf, padc, padn);
+                        break;
+                    case 'u':
+                        value.v_uint64 = va_arg(args, uint32_t);
+                        debug_ds(value.v_uint64 & 0xFFFFFFFF, buf, 0, 0);
+                        debugsp(level, buf, padc, padn);
+                        break;
+                    case 'x':
+                        value.v_uint64 = va_arg(args, uint32_t);
+                        debug_xs(value.v_uint64 & 0xFFFFFFFF, buf, s_debug_xs_set0);
+                        debugsp(level, buf, padc, padn);
+                        break;
+                    case 'X':
+                        value.v_uint64 = va_arg(args, uint32_t);
+                        debug_xs(value.v_uint64 & 0xFFFFFFFF, buf, s_debug_xs_set1);
+                        debugsp(level, buf, padc, padn);
+                        break;
+                    case 'p':
+                        value.v_ptr = va_arg(args, uintptr_t);
+                        debugc(level, '0');
+                        debugc(level, 'x');
+                        debug_xs(value.v_ptr, buf, s_debug_xs_set0);
+                        debugspl(level, buf, '0', sizeof(uintptr_t) * 2);
+                        break;
+                    case 's':
+                        value.v_string = va_arg(args, const char *);
+                        debugsp(level, value.v_string ? value.v_string : "(null)", padc, padn);
+                        break;
+                    default:
+                        debugc(level, '%');
+                        debugc(level, c);
+                        break;
+                }
+                break;
+            default:
+                debugc(level, c);
+                break;
+        }
+
+        ++fmt;
+    }
+}
+
diff --git a/src/sys/debug.h b/src/sys/debug.h
new file mode 100644
index 0000000..d5ca6cc
--- /dev/null
+++ b/src/sys/debug.h
@@ -0,0 +1,31 @@
+#pragma once
+#include <stdarg.h>
+#include <stdint.h>
+#include <stddef.h>
+
+#define DEBUG_DEFAULT   0
+#define DEBUG_INFO      1
+#define DEBUG_WARN      2
+#define DEBUG_ERROR     3
+#define DEBUG_FATAL     4
+
+#define DEBUG_OUT_SERIAL    0
+#define DEBUG_OUT_DISP      1
+
+#define kdebug(f, ...) debugf(DEBUG_DEFAULT, "[%s] " f, __func__, ##__VA_ARGS__)
+#define kinfo(f, ...) debugf(DEBUG_INFO, "[%s] " f, __func__, ##__VA_ARGS__)
+#define kwarn(f, ...) debugf(DEBUG_WARN, "[%s] " f, __func__, ##__VA_ARGS__)
+#define kerror(f, ...) debugf(DEBUG_ERROR, "[%s] " f, __func__, ##__VA_ARGS__)
+#define kfatal(f, ...) debugf(DEBUG_FATAL, "[%s] " f, __func__, ##__VA_ARGS__)
+#define kprint(l, f, ...) debugf(l, "[%s] " f, __func__, ##__VA_ARGS__)
+
+void debugc(int level, char c);
+void debugs(int level, const char *s);
+
+void debug_xs(uint64_t v, char *res, const char *set);
+void debug_ds(int64_t x, char *res, int s, int sz);
+void debug_init(void);
+void debugf(int level, const char *fmt, ...);
+void debugfv(int level, const char *fmt, va_list args);
+
+void debug_dump(int level, const void *block, size_t count);
diff --git a/src/sys/mem.c b/src/sys/mem.c
new file mode 100644
index 0000000..fe6dad0
--- /dev/null
+++ b/src/sys/mem.c
@@ -0,0 +1,8 @@
+#include "mem.h"
+
+void *memset(void *blk, int v, size_t sz) {
+    for (size_t i = 0; i < sz; ++i) {
+        ((char *) blk)[i] = v;
+    }
+    return blk;
+}
diff --git a/src/sys/mem.h b/src/sys/mem.h
new file mode 100644
index 0000000..5a0580f
--- /dev/null
+++ b/src/sys/mem.h
@@ -0,0 +1,5 @@
+#pragma once
+#include <stdint.h>
+#include <stddef.h>
+
+void *memset(void *blk, int v, size_t sz);
diff --git a/src/sys/string.c b/src/sys/string.c
new file mode 100644
index 0000000..bbedab2
--- /dev/null
+++ b/src/sys/string.c
@@ -0,0 +1,9 @@
+#include "string.h"
+
+size_t strlen(const char *a) {
+    size_t s = 0;
+    while (*a++) {
+        ++s;
+    }
+    return s;
+}
diff --git a/src/sys/string.h b/src/sys/string.h
new file mode 100644
index 0000000..1679ac4
--- /dev/null
+++ b/src/sys/string.h
@@ -0,0 +1,4 @@
+#pragma once
+#include <stddef.h>
+
+size_t strlen(const char *s);