diff --git a/src/build/arch/x64/Move.go b/src/build/arch/x64/Move.go
index 82f5869..cac1d09 100644
--- a/src/build/arch/x64/Move.go
+++ b/src/build/arch/x64/Move.go
@@ -4,13 +4,14 @@ import (
 	"encoding/binary"
 
 	"git.akyoto.dev/cli/q/src/build/cpu"
+	"git.akyoto.dev/cli/q/src/build/sizeof"
 )
 
 // MoveRegisterNumber moves an integer into the given register.
 func MoveRegisterNumber(code []byte, destination cpu.Register, number int) []byte {
 	w := byte(0)
 
-	if SizeOf(int64(number)) == 8 {
+	if sizeof.Signed(int64(number)) == 8 {
 		w = 1
 	}
 
diff --git a/src/build/arch/x64/SizeOf_test.go b/src/build/arch/x64/SizeOf_test.go
deleted file mode 100644
index eb84a59..0000000
--- a/src/build/arch/x64/SizeOf_test.go
+++ /dev/null
@@ -1,21 +0,0 @@
-package x64_test
-
-import (
-	"math"
-	"testing"
-
-	"git.akyoto.dev/cli/q/src/build/arch/x64"
-	"git.akyoto.dev/go/assert"
-)
-
-func TestSizeOf(t *testing.T) {
-	assert.Equal(t, x64.SizeOf(0), 1)
-	assert.Equal(t, x64.SizeOf(math.MinInt8), 1)
-	assert.Equal(t, x64.SizeOf(math.MaxInt8), 1)
-	assert.Equal(t, x64.SizeOf(math.MinInt16), 2)
-	assert.Equal(t, x64.SizeOf(math.MaxInt16), 2)
-	assert.Equal(t, x64.SizeOf(math.MinInt32), 4)
-	assert.Equal(t, x64.SizeOf(math.MaxInt32), 4)
-	assert.Equal(t, x64.SizeOf(math.MinInt64), 8)
-	assert.Equal(t, x64.SizeOf(math.MaxInt64), 8)
-}
diff --git a/src/build/arch/x64/encodeNum.go b/src/build/arch/x64/encodeNum.go
index 2053dfb..a9a3313 100644
--- a/src/build/arch/x64/encodeNum.go
+++ b/src/build/arch/x64/encodeNum.go
@@ -4,11 +4,12 @@ import (
 	"encoding/binary"
 
 	"git.akyoto.dev/cli/q/src/build/cpu"
+	"git.akyoto.dev/cli/q/src/build/sizeof"
 )
 
 // encodeNum encodes an instruction with up to two registers and a number parameter.
 func encodeNum(code []byte, mod AddressMode, reg cpu.Register, rm cpu.Register, number int, opCode8 byte, opCode32 byte) []byte {
-	if SizeOf(int64(number)) == 1 {
+	if sizeof.Signed(int64(number)) == 1 {
 		code = encode(code, mod, reg, rm, 8, opCode8)
 		return append(code, byte(number))
 	}
diff --git a/src/build/asm/Finalize.go b/src/build/asm/Finalize.go
index e38a83f..7094fe2 100644
--- a/src/build/asm/Finalize.go
+++ b/src/build/asm/Finalize.go
@@ -7,6 +7,7 @@ import (
 	"git.akyoto.dev/cli/q/src/build/arch/x64"
 	"git.akyoto.dev/cli/q/src/build/config"
 	"git.akyoto.dev/cli/q/src/build/elf"
+	"git.akyoto.dev/cli/q/src/build/sizeof"
 )
 
 // Finalize generates the final machine code.
@@ -242,7 +243,7 @@ restart:
 	for i, pointer := range pointers {
 		address := pointer.Resolve()
 
-		if x64.SizeOf(int64(address)) > int(pointer.Size) {
+		if sizeof.Signed(int64(address)) > int(pointer.Size) {
 			left := code[:pointer.Position-Address(pointer.OpSize)]
 			right := code[pointer.Position+Address(pointer.Size):]
 			size := pointer.Size + pointer.OpSize
diff --git a/src/build/core/CompileAssignArray.go b/src/build/core/CompileAssignArray.go
index f519ea0..167d3e3 100644
--- a/src/build/core/CompileAssignArray.go
+++ b/src/build/core/CompileAssignArray.go
@@ -21,7 +21,7 @@ func (f *Function) CompileAssignArray(node *ast.Assign) error {
 	defer f.UseVariable(variable)
 
 	index := left.Children[1]
-	offset, _, err := f.Number(index.Token)
+	offset, err := f.Number(index.Token)
 
 	if err != nil {
 		return err
diff --git a/src/build/core/ExecuteLeaf.go b/src/build/core/ExecuteLeaf.go
index 6dd7645..fe78ef6 100644
--- a/src/build/core/ExecuteLeaf.go
+++ b/src/build/core/ExecuteLeaf.go
@@ -21,7 +21,7 @@ func (f *Function) ExecuteLeaf(operation token.Token, register cpu.Register, ope
 		return f.ExecuteRegisterRegister(operation, register, variable.Register)
 
 	case token.Number, token.Rune:
-		number, _, err := f.Number(operand)
+		number, err := f.Number(operand)
 
 		if err != nil {
 			return err
diff --git a/src/build/core/ExpressionToMemory.go b/src/build/core/ExpressionToMemory.go
index af7ec37..d876c7b 100644
--- a/src/build/core/ExpressionToMemory.go
+++ b/src/build/core/ExpressionToMemory.go
@@ -4,18 +4,21 @@ import (
 	"git.akyoto.dev/cli/q/src/build/asm"
 	"git.akyoto.dev/cli/q/src/build/errors"
 	"git.akyoto.dev/cli/q/src/build/expression"
+	"git.akyoto.dev/cli/q/src/build/sizeof"
 	"git.akyoto.dev/cli/q/src/build/token"
 )
 
 // ExpressionToMemory puts the result of an expression into the specified memory address.
 func (f *Function) ExpressionToMemory(node *expression.Expression, memory asm.Memory) error {
 	if node.IsLeaf() && (node.Token.Kind == token.Number || node.Token.Kind == token.Rune) {
-		number, size, err := f.Number(node.Token)
+		number, err := f.Number(node.Token)
 
 		if err != nil {
 			return err
 		}
 
+		size := byte(sizeof.Signed(int64(number)))
+
 		if size != memory.Length {
 			return errors.New(&errors.NumberExceedsBounds{Number: number, ExpectedSize: memory.Length, Size: size}, f.File, node.Token.Position)
 		}
diff --git a/src/build/core/Number.go b/src/build/core/Number.go
index 2cc05a1..f6c14cd 100644
--- a/src/build/core/Number.go
+++ b/src/build/core/Number.go
@@ -10,45 +10,45 @@ import (
 )
 
 // Number tries to convert the token into a numeric value.
-func (f *Function) Number(t token.Token) (int, byte, error) {
+func (f *Function) Number(t token.Token) (int, error) {
 	switch t.Kind {
 	case token.Number:
 		digits := t.Text(f.File.Bytes)
 
 		if strings.HasPrefix(digits, "0x") {
 			number, err := strconv.ParseInt(digits[2:], 16, 64)
-			return int(number), 8, err
+			return int(number), err
 		}
 
 		if strings.HasPrefix(digits, "0o") {
 			number, err := strconv.ParseInt(digits[2:], 8, 64)
-			return int(number), 8, err
+			return int(number), err
 		}
 
 		if strings.HasPrefix(digits, "0b") {
 			number, err := strconv.ParseInt(digits[2:], 2, 64)
-			return int(number), 8, err
+			return int(number), err
 		}
 
 		number, err := strconv.Atoi(digits)
-		return number, 8, err
+		return number, err
 
 	case token.Rune:
 		r := t.Bytes(f.File.Bytes)
 		r = r[1 : len(r)-1]
 
 		if len(r) == 0 {
-			return 0, 0, errors.New(errors.InvalidRune, f.File, t.Position+1)
+			return 0, errors.New(errors.InvalidRune, f.File, t.Position+1)
 		}
 
 		number, size := utf8.DecodeRune(r)
 
 		if len(r) > size {
-			return 0, 0, errors.New(errors.InvalidRune, f.File, t.Position+1)
+			return 0, errors.New(errors.InvalidRune, f.File, t.Position+1)
 		}
 
-		return int(number), byte(size), nil
+		return int(number), nil
 	}
 
-	return 0, 0, errors.New(errors.InvalidNumber, f.File, t.Position)
+	return 0, errors.New(errors.InvalidNumber, f.File, t.Position)
 }
diff --git a/src/build/core/TokenToRegister.go b/src/build/core/TokenToRegister.go
index 50e2b77..e95d87d 100644
--- a/src/build/core/TokenToRegister.go
+++ b/src/build/core/TokenToRegister.go
@@ -26,7 +26,7 @@ func (f *Function) TokenToRegister(t token.Token, register cpu.Register) error {
 		return nil
 
 	case token.Number, token.Rune:
-		number, _, err := f.Number(t)
+		number, err := f.Number(t)
 
 		if err != nil {
 			return err
diff --git a/src/build/arch/x64/SizeOf.go b/src/build/sizeof/Signed.go
similarity index 67%
rename from src/build/arch/x64/SizeOf.go
rename to src/build/sizeof/Signed.go
index 6c7293a..a0fee4a 100644
--- a/src/build/arch/x64/SizeOf.go
+++ b/src/build/sizeof/Signed.go
@@ -1,9 +1,9 @@
-package x64
+package sizeof
 
 import "math"
 
-// SizeOf tells you how many bytes are needed to encode this number.
-func SizeOf(number int64) int {
+// Signed tells you how many bytes are needed to encode this signed number.
+func Signed(number int64) int {
 	switch {
 	case number >= math.MinInt8 && number <= math.MaxInt8:
 		return 1
diff --git a/src/build/sizeof/Signed_test.go b/src/build/sizeof/Signed_test.go
new file mode 100644
index 0000000..6ddc15f
--- /dev/null
+++ b/src/build/sizeof/Signed_test.go
@@ -0,0 +1,21 @@
+package sizeof_test
+
+import (
+	"math"
+	"testing"
+
+	"git.akyoto.dev/cli/q/src/build/sizeof"
+	"git.akyoto.dev/go/assert"
+)
+
+func TestSigned(t *testing.T) {
+	assert.Equal(t, sizeof.Signed(0), 1)
+	assert.Equal(t, sizeof.Signed(math.MinInt8), 1)
+	assert.Equal(t, sizeof.Signed(math.MaxInt8), 1)
+	assert.Equal(t, sizeof.Signed(math.MinInt16), 2)
+	assert.Equal(t, sizeof.Signed(math.MaxInt16), 2)
+	assert.Equal(t, sizeof.Signed(math.MinInt32), 4)
+	assert.Equal(t, sizeof.Signed(math.MaxInt32), 4)
+	assert.Equal(t, sizeof.Signed(math.MinInt64), 8)
+	assert.Equal(t, sizeof.Signed(math.MaxInt64), 8)
+}
diff --git a/src/build/sizeof/Unsigned.go b/src/build/sizeof/Unsigned.go
new file mode 100644
index 0000000..949b77a
--- /dev/null
+++ b/src/build/sizeof/Unsigned.go
@@ -0,0 +1,20 @@
+package sizeof
+
+import "math"
+
+// Unsigned tells you how many bytes are needed to encode this unsigned number.
+func Unsigned(number uint64) int {
+	switch {
+	case number <= math.MaxUint8:
+		return 1
+
+	case number <= math.MaxUint16:
+		return 2
+
+	case number <= math.MaxUint32:
+		return 4
+
+	default:
+		return 8
+	}
+}
diff --git a/src/build/sizeof/Unsigned_test.go b/src/build/sizeof/Unsigned_test.go
new file mode 100644
index 0000000..e9a5dc8
--- /dev/null
+++ b/src/build/sizeof/Unsigned_test.go
@@ -0,0 +1,17 @@
+package sizeof_test
+
+import (
+	"math"
+	"testing"
+
+	"git.akyoto.dev/cli/q/src/build/sizeof"
+	"git.akyoto.dev/go/assert"
+)
+
+func TestUnsigned(t *testing.T) {
+	assert.Equal(t, sizeof.Unsigned(0), 1)
+	assert.Equal(t, sizeof.Unsigned(math.MaxUint8), 1)
+	assert.Equal(t, sizeof.Unsigned(math.MaxUint16), 2)
+	assert.Equal(t, sizeof.Unsigned(math.MaxUint32), 4)
+	assert.Equal(t, sizeof.Unsigned(math.MaxUint64), 8)
+}