diff --git a/asm/arithmetic.asm b/asm/arithmetic.asm
new file mode 100644
index 0000000..0db68bf
--- /dev/null
+++ b/asm/arithmetic.asm
@@ -0,0 +1,26 @@
+/// Adds two 16-bit integers
+@macro add16 (%h0:reg, %l0:reg, %h1:reg|imm, %l1:reg|imm) {
+    add %l0, %l1
+    adc %h0, %h1
+}
+
+/// Subtracts two 16-bit integers
+@macro sub16 (%h0:reg, %l0:reg, %h1:reg|imm, %l1:reg|imm) {
+    sub %l0, %l1
+    sbc %h0, %h1
+}
+
+/// Increments the given byte
+@macro inc (%reg:reg) {
+    add %reg, 1
+}
+
+/// Decrements the given byte
+@macro dec (%reg:reg) {
+    sub %reg, 1
+}
+
+/// Bitwise inverts the given byte
+@macro not (%reg:reg) {
+    nand %reg, %reg
+}
diff --git a/asm/macros.asm b/asm/flow.asm
similarity index 59%
rename from asm/macros.asm
rename to asm/flow.asm
index e61803f..a99333e 100644
--- a/asm/macros.asm
+++ b/asm/flow.asm
@@ -1,19 +1,3 @@
-/// Adds two 16-bit integers
-@macro add16 (%h0:reg, %l0:reg, %h1:reg|imm, %l1:reg|imm) {
-    add %l0, %l1
-    adc %h0, %h1
-}
-
-/// Subtracts two 16-bit integers
-@macro sub16 (%h0:reg, %l0:reg, %h1:reg|imm, %l1:reg|imm) {
-    sub %l0, %l1
-    sbc %h0, %h1
-}
-
-@macro dec (%reg:reg) {
-    sub %reg, 1
-}
-
 @macro jmp {
     () {
         jnz 1
diff --git a/asm/util.asm b/asm/util.asm
new file mode 100644
index 0000000..cb4d80b
--- /dev/null
+++ b/asm/util.asm
@@ -0,0 +1,63 @@
+@macro push {
+    ; push two registers
+    (%r0:reg, %r1:reg) {
+        push %r0
+        push %r1
+    }
+    ; push three registers
+    (%r0:reg, %r1:reg, %r2:reg) {
+        push %r0
+        push %r1, %r2
+    }
+    ; push four registers
+    (%r0:reg, %r1:reg, %r2:reg, %r3:reg) {
+        push %r0
+        push %r1, %r2, %r3
+    }
+    ; push five registers
+    (%r0:reg, %r1:reg, %r2:reg, %r3:reg, %r4:reg) {
+        push %r0
+        push %r1, %r2, %r3, %r4
+    }
+    ; push six registers
+    (%r0:reg, %r1:reg, %r2:reg, %r3:reg, %r4:reg, %r5:reg) {
+        push %r0
+        push %r1, %r2, %r3, %r4, %r5
+    }
+}
+
+@macro pop {
+    ; pop two registers
+    (%r0:reg, %r1:reg) {
+        pop %r0
+        pop %r1
+    }
+    ; pop three registers
+    (%r0:reg, %r1:reg, %r2:reg) {
+        pop %r0
+        pop %r1, %r2
+    }
+    ; pop four registers
+    (%r0:reg, %r1:reg, %r2:reg, %r3:reg) {
+        pop %r0
+        pop %r1, %r2, %r3
+    }
+    ; pop five registers
+    (%r0:reg, %r1:reg, %r2:reg, %r3:reg, %r4:reg) {
+        pop %r0
+        pop %r1, %r2, %r3, %r4
+    }
+    ; pop six registers
+    (%r0:reg, %r1:reg, %r2:reg, %r3:reg, %r4:reg, %r5:reg) {
+        pop %r0
+        pop %r1, %r2, %r3, %r4, %r5
+    }
+}
+
+@macro pusha () {
+    push A, B, C, D, E, F
+}
+
+@macro popa () {
+    pop F, E, D, C, B, A
+}
diff --git a/src/assembler/include.rs b/src/assembler/include.rs
index 9ab2be4..d5aa281 100644
--- a/src/assembler/include.rs
+++ b/src/assembler/include.rs
@@ -9,7 +9,9 @@ use clio::Input;
 use phf::{phf_map, Map};
 
 static BUILT_INS: Map<&'static str, &str> = phf_map! {
-    "macros" => include_str!("../../asm/macros.asm"),
+    "arithmetic" => include_str!("../../asm/arithmetic.asm"),
+    "flow" => include_str!("../../asm/flow.asm"),
+    "util" => include_str!("../../asm/util.asm"),
 };
 
 pub fn include(path: Path) -> Result<TokenStream, Errors> {
diff --git a/tests/fib.asm b/tests/fib.asm
index d2a1da5..44de80e 100644
--- a/tests/fib.asm
+++ b/tests/fib.asm
@@ -3,7 +3,8 @@
 @org 0x0000
 @define COUNT 7
 
-@include <macros>
+@include <arithmetic>
+@include <flow>
 
 _start:
     mv A, COUNT