diff --git a/.gitignore b/.gitignore
index 167f0e63..096540b0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -110,6 +110,7 @@
 /examples/generic_file
 /examples/generic_malloc
 /examples/generic_mutex
+/examples/macro_bits
 /examples/macro_container_of
 /examples/memmap
 /examples/ntoa
diff --git a/ChangeLog b/ChangeLog
index 9305dd34..c53b6469 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2022-06-30  Alex Kotov  <kotovalexarian@gmail.com>
+
+	* include/kernaux/macro.h: Added macros "KERNAUX_BITS[8|16|32|64]"
+
+2022-06-27  Alex Kotov  <kotovalexarian@gmail.com>
+
+	* include/kernaux/macro.h: Added macro "KERNAUX_CONTAINER_OF"
+
 2022-06-25  Alex Kotov  <kotovalexarian@gmail.com>
 
 	* configure.ac: Removed package "io"
diff --git a/README.md b/README.md
index 1905158e..7ab6533f 100644
--- a/README.md
+++ b/README.md
@@ -38,15 +38,15 @@ We use [semantic versioning](https://semver.org) for stable APIs. Stable APIs
 can only change when major version number is increased (or minor while major is
 zero). Work-in-progress APIs can change at any time.
 
-* Runtime environment
+* Basic features
   * [Feature macros](/include/kernaux/version.h.in) (*work in progress*)
+  * [Macros](/include/kernaux/macro.h) (*non-breaking since* **?.?.?**)
+    * [Example: CONTAINER_OF](/examples/macro_container_of.c)
+    * [Example: BITS](/examples/macro_bits.c)
   * [Assertions](/include/kernaux/assert.h) (*non-breaking since* **0.4.0**)
     * [Example: Assert](/examples/assert.c)
     * [Example: Panic](/examples/panic.c)
   * Stack trace *(planned)*
-  * Architecture-specific code (*work in progress*)
-    * [Declarations](/include/kernaux/arch/)
-    * [Functions](/include/kernaux/asm/)
 * Generic types
   * [File](/include/kernaux/generic/file.h) (*non-breaking since* **?.?.?**)
     * [Example](/examples/generic_file.c)
@@ -86,6 +86,9 @@ zero). Work-in-progress APIs can change at any time.
   * [stdlib.h](/libc/include/stdlib.h)
   * [string.h](/libc/include/string.h)
   * [sys/types.h](/libc/include/sys/types.h)
+* Architecture-specific code (*work in progress*)
+  * [Declarations](/include/kernaux/arch/)
+  * [Functions](/include/kernaux/asm/)
 * Device drivers (for debugging only)
   * [Serial console](/include/kernaux/drivers/console.h) (*work in progress*)
   * [Framebuffer](/include/kernaux/drivers/framebuffer.h) (*planned*)
diff --git a/examples/Makefile.am b/examples/Makefile.am
index a9ce7706..31bc40fa 100644
--- a/examples/Makefile.am
+++ b/examples/Makefile.am
@@ -45,6 +45,14 @@ TESTS += generic_mutex
 generic_mutex_LDADD = $(top_builddir)/libkernaux.la
 generic_mutex_SOURCES = main.c generic_mutex.c
 
+##############
+# macro_bits #
+##############
+
+TESTS += macro_bits
+macro_bits_LDADD = $(top_builddir)/libkernaux.la
+macro_bits_SOURCES = main.c macro_bits.c
+
 ######################
 # macro_container_of #
 ######################
diff --git a/examples/macro_bits.c b/examples/macro_bits.c
new file mode 100644
index 00000000..c470a7a9
--- /dev/null
+++ b/examples/macro_bits.c
@@ -0,0 +1,21 @@
+#include <kernaux/macro.h>
+
+#include <assert.h>
+
+void example_main()
+{
+    assert(KERNAUX_BITS(0)    == 0x1);
+    assert(KERNAUX_BITS(31)   == 0x80000000);
+
+    assert(KERNAUX_BITS8(0)   == 0x1);
+    assert(KERNAUX_BITS8(7)   == 0x80);
+
+    assert(KERNAUX_BITS16(0)  == 0x1);
+    assert(KERNAUX_BITS16(15) == 0x8000);
+
+    assert(KERNAUX_BITS32(0)  == 0x1);
+    assert(KERNAUX_BITS32(31) == 0x80000000);
+
+    assert(KERNAUX_BITS64(0)  == 0x1);
+    assert(KERNAUX_BITS64(63) == 0x8000000000000000);
+}
diff --git a/include/kernaux/arch/i386.h b/include/kernaux/arch/i386.h
index 0a8a3ce5..1622004e 100644
--- a/include/kernaux/arch/i386.h
+++ b/include/kernaux/arch/i386.h
@@ -28,27 +28,27 @@ extern "C" {
     KERNAUX_ARCH_I386_ADDR_TO_PDE_ADDR(addr)
 
 // CR0 bits
-#define KERNAUX_ARCH_I386_CR0_PE ((uint32_t)0x00000001) // 0:  Protected Mode Enable
-#define KERNAUX_ARCH_I386_CR0_MP ((uint32_t)0x00000002) // 1:  Monitor co-processor
-#define KERNAUX_ARCH_I386_CR0_EM ((uint32_t)0x00000004) // 2:  x87 FPU Emulation
-#define KERNAUX_ARCH_I386_CR0_TS ((uint32_t)0x00000008) // 3:  Task switched
-#define KERNAUX_ARCH_I386_CR0_ET ((uint32_t)0x00000010) // 4:  Extension type
-#define KERNAUX_ARCH_I386_CR0_NE ((uint32_t)0x00000020) // 5:  Numeric error
-#define KERNAUX_ARCH_I386_CR0_WP ((uint32_t)0x00010000) // 16: Write protect
-#define KERNAUX_ARCH_I386_CR0_AM ((uint32_t)0x00040000) // 18: Alignment mask
-#define KERNAUX_ARCH_I386_CR0_NW ((uint32_t)0x20000000) // 29: Not-write trough
-#define KERNAUX_ARCH_I386_CR0_CD ((uint32_t)0x40000000) // 30: Cache disable
-#define KERNAUX_ARCH_I386_CR0_PG ((uint32_t)0x80000000) // 31: Paging
+#define KERNAUX_ARCH_I386_CR0_PE KERNAUX_BITS32(0)  // 0:  Protected Mode Enable
+#define KERNAUX_ARCH_I386_CR0_MP KERNAUX_BITS32(1)  // 1:  Monitor co-processor
+#define KERNAUX_ARCH_I386_CR0_EM KERNAUX_BITS32(2)  // 2:  x87 FPU Emulation
+#define KERNAUX_ARCH_I386_CR0_TS KERNAUX_BITS32(3)  // 3:  Task switched
+#define KERNAUX_ARCH_I386_CR0_ET KERNAUX_BITS32(4)  // 4:  Extension type
+#define KERNAUX_ARCH_I386_CR0_NE KERNAUX_BITS32(5)  // 5:  Numeric error
+#define KERNAUX_ARCH_I386_CR0_WP KERNAUX_BITS32(16) // 16: Write protect
+#define KERNAUX_ARCH_I386_CR0_AM KERNAUX_BITS32(18) // 18: Alignment mask
+#define KERNAUX_ARCH_I386_CR0_NW KERNAUX_BITS32(29) // 29: Not-write trough
+#define KERNAUX_ARCH_I386_CR0_CD KERNAUX_BITS32(30) // 30: Cache disable
+#define KERNAUX_ARCH_I386_CR0_PG KERNAUX_BITS32(31) // 31: Paging
 
 // Some CR4 bits
-#define KERNAUX_ARCH_I386_CR4_VME ((uint32_t)0x00000001) // 0: Virtual 8086 Mode Extensions
-#define KERNAUX_ARCH_I386_CR4_PVI ((uint32_t)0x00000002) // 1: Protected-mode Virtual Interrupts
-#define KERNAUX_ARCH_I386_CR4_TSD ((uint32_t)0x00000004) // 2: Time Stamp Disable
-#define KERNAUX_ARCH_I386_CR4_DE  ((uint32_t)0x00000008) // 3: Debugging Extensions
-#define KERNAUX_ARCH_I386_CR4_PSE ((uint32_t)0x00000010) // 4: Page Size Extension
-#define KERNAUX_ARCH_I386_CR4_PAE ((uint32_t)0x00000020) // 5: Physical Address Extension
-#define KERNAUX_ARCH_I386_CR4_MCE ((uint32_t)0x00000040) // 6: Machine Check Exception
-#define KERNAUX_ARCH_I386_CR4_PGE ((uint32_t)0x00000080) // 7: Page Global Enabled
+#define KERNAUX_ARCH_I386_CR4_VME KERNAUX_BITS32(0) // 0: Virtual 8086 Mode Extensions
+#define KERNAUX_ARCH_I386_CR4_PVI KERNAUX_BITS32(1) // 1: Protected-mode Virtual Interrupts
+#define KERNAUX_ARCH_I386_CR4_TSD KERNAUX_BITS32(2) // 2: Time Stamp Disable
+#define KERNAUX_ARCH_I386_CR4_DE  KERNAUX_BITS32(3) // 3: Debugging Extensions
+#define KERNAUX_ARCH_I386_CR4_PSE KERNAUX_BITS32(4) // 4: Page Size Extension
+#define KERNAUX_ARCH_I386_CR4_PAE KERNAUX_BITS32(5) // 5: Physical Address Extension
+#define KERNAUX_ARCH_I386_CR4_MCE KERNAUX_BITS32(6) // 6: Machine Check Exception
+#define KERNAUX_ARCH_I386_CR4_PGE KERNAUX_BITS32(7) // 7: Page Global Enabled
 // TODO: bits 8-31
 
 #include <kernaux/macro/packing_start.run>
diff --git a/include/kernaux/macro.h b/include/kernaux/macro.h
index be4c3d0b..e31c1f59 100644
--- a/include/kernaux/macro.h
+++ b/include/kernaux/macro.h
@@ -11,6 +11,13 @@ extern "C" {
 #define KERNAUX_CONTAINER_OF(ptr, type, member) \
     ((type*)((uintptr_t)(ptr) - offsetof(type, member)))
 
+#define KERNAUX_BITS(n) (1u << (n))
+
+#define KERNAUX_BITS8(n)  ((uint8_t )(((uint8_t )1) << (n)))
+#define KERNAUX_BITS16(n) ((uint16_t)(((uint16_t)1) << (n)))
+#define KERNAUX_BITS32(n) ((uint32_t)(((uint32_t)1) << (n)))
+#define KERNAUX_BITS64(n) ((uint64_t)(((uint64_t)1) << (n)))
+
 #ifdef KERNAUX_ACCESS_PRIVATE
 #   define KERNAUX_PRIVATE_FIELD(id) id
 #   define KERNAUX_PROTECTED_FIELD(id) id
diff --git a/include/kernaux/multiboot2.h.in b/include/kernaux/multiboot2.h.in
index 728d37e2..b2a38db3 100644
--- a/include/kernaux/multiboot2.h.in
+++ b/include/kernaux/multiboot2.h.in
@@ -38,8 +38,8 @@ extern "C" {
 
 #define KERNAUX_MULTIBOOT2_HTAG_BASE_FLAG_OPTIONAL 1
 
-#define KERNAUX_MULTIBOOT2_HTAG_FLAGS_REQUIRE_CONSOLE (1 << 0)
-#define KERNAUX_MULTIBOOT2_HTAG_FLAGS_EGA_SUPPORT     (1 << 1)
+#define KERNAUX_MULTIBOOT2_HTAG_FLAGS_REQUIRE_CONSOLE KERNAUX_BITS(0)
+#define KERNAUX_MULTIBOOT2_HTAG_FLAGS_EGA_SUPPORT     KERNAUX_BITS(1)
 
 #include <kernaux/macro/packing_start.run>
 
diff --git a/include/kernaux/printf_fmt.h b/include/kernaux/printf_fmt.h
index 4ee3b8f5..2b0b3584 100644
--- a/include/kernaux/printf_fmt.h
+++ b/include/kernaux/printf_fmt.h
@@ -5,20 +5,22 @@
 extern "C" {
 #endif
 
+#include <kernaux/macro.h>
+
 #include <stdbool.h>
 
-#define KERNAUX_PRINTF_FMT_FLAGS_ZEROPAD   (1u <<  0u)
-#define KERNAUX_PRINTF_FMT_FLAGS_LEFT      (1u <<  1u)
-#define KERNAUX_PRINTF_FMT_FLAGS_PLUS      (1u <<  2u)
-#define KERNAUX_PRINTF_FMT_FLAGS_SPACE     (1u <<  3u)
-#define KERNAUX_PRINTF_FMT_FLAGS_HASH      (1u <<  4u)
-#define KERNAUX_PRINTF_FMT_FLAGS_UPPERCASE (1u <<  5u)
-#define KERNAUX_PRINTF_FMT_FLAGS_CHAR      (1u <<  6u)
-#define KERNAUX_PRINTF_FMT_FLAGS_SHORT     (1u <<  7u)
-#define KERNAUX_PRINTF_FMT_FLAGS_LONG      (1u <<  8u)
-#define KERNAUX_PRINTF_FMT_FLAGS_LONG_LONG (1u <<  9u)
-#define KERNAUX_PRINTF_FMT_FLAGS_PRECISION (1u << 10u)
-#define KERNAUX_PRINTF_FMT_FLAGS_ADAPT_EXP (1u << 11u)
+#define KERNAUX_PRINTF_FMT_FLAGS_ZEROPAD   KERNAUX_BITS(0)
+#define KERNAUX_PRINTF_FMT_FLAGS_LEFT      KERNAUX_BITS(1)
+#define KERNAUX_PRINTF_FMT_FLAGS_PLUS      KERNAUX_BITS(2)
+#define KERNAUX_PRINTF_FMT_FLAGS_SPACE     KERNAUX_BITS(3)
+#define KERNAUX_PRINTF_FMT_FLAGS_HASH      KERNAUX_BITS(4)
+#define KERNAUX_PRINTF_FMT_FLAGS_UPPERCASE KERNAUX_BITS(5)
+#define KERNAUX_PRINTF_FMT_FLAGS_CHAR      KERNAUX_BITS(6)
+#define KERNAUX_PRINTF_FMT_FLAGS_SHORT     KERNAUX_BITS(7)
+#define KERNAUX_PRINTF_FMT_FLAGS_LONG      KERNAUX_BITS(8)
+#define KERNAUX_PRINTF_FMT_FLAGS_LONG_LONG KERNAUX_BITS(9)
+#define KERNAUX_PRINTF_FMT_FLAGS_PRECISION KERNAUX_BITS(10)
+#define KERNAUX_PRINTF_FMT_FLAGS_ADAPT_EXP KERNAUX_BITS(11)
 
 enum KernAux_PrintfFmt_Type {
     KERNAUX_PRINTF_FMT_TYPE_NONE,
diff --git a/src/drivers/intel_8259_pic.c b/src/drivers/intel_8259_pic.c
index 39d0bc10..430d536a 100644
--- a/src/drivers/intel_8259_pic.c
+++ b/src/drivers/intel_8259_pic.c
@@ -4,6 +4,7 @@
 
 #include <kernaux/assert.h>
 #include <kernaux/drivers/intel_8259_pic.h>
+#include <kernaux/macro.h>
 
 #ifdef ASM_I386
 #include <kernaux/asm/i386.h>
@@ -47,10 +48,10 @@ void kernaux_drivers_intel_8259_pic_enable(const unsigned char number)
 
     if (number < IRQS_COUNT) {
         const uint8_t mask = inportb(MASTER_DATA_PORT);
-        outportb(MASTER_DATA_PORT, mask & ~(1 << number));
+        outportb(MASTER_DATA_PORT, mask & ~KERNAUX_BITS8(number));
     } else {
         const uint8_t mask = inportb(SLAVE_DATA_PORT);
-        outportb(SLAVE_DATA_PORT, mask & ~(1 << (number - IRQS_COUNT)));
+        outportb(SLAVE_DATA_PORT, mask & ~KERNAUX_BITS8((number - IRQS_COUNT)));
     }
 }
 
@@ -60,10 +61,10 @@ void kernaux_drivers_intel_8259_pic_disable(const unsigned char number)
 
     if (number < IRQS_COUNT) {
         const uint8_t mask = inportb(MASTER_DATA_PORT);
-        outportb(MASTER_DATA_PORT, mask | (1 << number));
+        outportb(MASTER_DATA_PORT, mask | KERNAUX_BITS8(number));
     } else {
         const uint8_t mask = inportb(SLAVE_DATA_PORT);
-        outportb(SLAVE_DATA_PORT, mask | (1 << (number - IRQS_COUNT)));
+        outportb(SLAVE_DATA_PORT, mask | KERNAUX_BITS8((number - IRQS_COUNT)));
     }
 }
 
diff --git a/src/pfa.c b/src/pfa.c
index aeb83e05..4534a072 100644
--- a/src/pfa.c
+++ b/src/pfa.c
@@ -3,6 +3,7 @@
 #endif
 
 #include <kernaux/assert.h>
+#include <kernaux/macro.h>
 #include <kernaux/pfa.h>
 
 #include "libc.h"
@@ -10,7 +11,7 @@
 #define PAGE_INDEX(page_addr) ((page_addr) / KERNAUX_PFA_PAGE_SIZE)
 
 #define FLAG_INDEX_FROM_INDEX(page_index) ((page_index) / 8)
-#define FLAG_MASK_FROM_INDEX(page_index) (1 << ((page_index) % 8))
+#define FLAG_MASK_FROM_INDEX(page_index) KERNAUX_BITS((page_index) % 8)
 
 #define FLAG_INDEX_FROM_ADDR(page_addr) \
     (FLAG_INDEX_FROM_INDEX(PAGE_INDEX(page_addr)))