diff --git a/std/debug.zig b/std/debug.zig
index d1d52f677a..41034fa393 100644
--- a/std/debug.zig
+++ b/std/debug.zig
@@ -10,7 +10,7 @@ pub fn printStackTrace() {
     while (true) {
         const fp = maybe_fp ?? break;
         const return_address = *(&const usize)(usize(fp) + @sizeOf(usize));
-        %%io.stderr.print_u64(return_address);
+        %%io.stderr.printInt(usize, return_address);
         %%io.stderr.printf("\n");
         maybe_fp = *(&const ?&const u8)(fp);
     }
diff --git a/std/io.zig b/std/io.zig
index cf450164de..3897469834 100644
--- a/std/io.zig
+++ b/std/io.zig
@@ -94,23 +94,13 @@ pub struct OutStream {
         return byte_count;
     }
 
-    pub fn print_u64(os: &OutStream, x: u64) -> %usize {
+    pub fn printInt(os: &OutStream, inline T: type, x: T) -> %usize {
+        // TODO replace max_u64_base10_digits with math.log10(math.pow(2, @sizeOf(T)))
         if (os.index + max_u64_base10_digits >= os.buffer.len) {
             %return os.flush();
         }
-        const amt_printed = bufPrintUnsigned(u64, os.buffer[os.index...], x);
+        const amt_printed = bufPrintInt(T, os.buffer[os.index...], x);
         os.index += amt_printed;
-
-        return amt_printed;
-    }
-
-    pub fn print_i64(os: &OutStream, x: i64) -> %usize {
-        if (os.index + max_u64_base10_digits >= os.buffer.len) {
-            %return os.flush();
-        }
-        const amt_printed = bufPrintSigned(i64, os.buffer[os.index...], x);
-        os.index += amt_printed;
-
         return amt_printed;
     }
 
@@ -234,7 +224,11 @@ fn charToDigit(c: u8, radix: u8) -> %u8 {
     return if (value >= radix) error.InvalidChar else value;
 }
 
-pub fn bufPrintSigned(inline T: type, out_buf: []u8, x: T) -> usize {
+pub fn bufPrintInt(inline T: type, out_buf: []u8, x: T) -> usize {
+    if (T.is_signed) bufPrintSigned(T, out_buf, x) else bufPrintUnsigned(T, out_buf, x)
+}
+
+fn bufPrintSigned(inline T: type, out_buf: []u8, x: T) -> usize {
     const uint = @intType(false, T.bit_count);
     if (x < 0) {
         out_buf[0] = '-';
@@ -244,7 +238,7 @@ pub fn bufPrintSigned(inline T: type, out_buf: []u8, x: T) -> usize {
     }
 }
 
-pub fn bufPrintUnsigned(inline T: type, out_buf: []u8, x: T) -> usize {
+fn bufPrintUnsigned(inline T: type, out_buf: []u8, x: T) -> usize {
     var buf: [max_u64_base10_digits]u8 = undefined;
     var a = x;
     var index: usize = buf.len;
diff --git a/std/test_runner.zig b/std/test_runner.zig
index ab56890ebe..18dc5714aa 100644
--- a/std/test_runner.zig
+++ b/std/test_runner.zig
@@ -11,9 +11,9 @@ pub fn runTests() -> %void {
     for (zig_test_fn_list) |testFn, i| {
         // TODO: print var args
         %%io.stderr.write("Test ");
-        %%io.stderr.print_u64(i + 1);
+        %%io.stderr.printInt(@typeOf(i), i + 1);
         %%io.stderr.write("/");
-        %%io.stderr.print_u64(zig_test_fn_list.len);
+        %%io.stderr.printInt(@typeOf(zig_test_fn_list.len), zig_test_fn_list.len);
         %%io.stderr.write(" ");
         %%io.stderr.write(testFn.name);
         %%io.stderr.write("...");
diff --git a/test/run_tests.cpp b/test/run_tests.cpp
index 661fbfd756..f777551151 100644
--- a/test/run_tests.cpp
+++ b/test/run_tests.cpp
@@ -462,20 +462,20 @@ const io = @import("std").io;
 pub fn main(args: [][]u8) -> %void {
     const array = []u8 {9, 8, 7, 6};
     for (array) |item| {
-        %%io.stdout.print_u64(item);
+        %%io.stdout.printInt(@typeOf(item), item);
         %%io.stdout.printf("\n");
     }
     for (array) |item, index| {
-        %%io.stdout.print_u64(index);
+        %%io.stdout.printInt(@typeOf(index), index);
         %%io.stdout.printf("\n");
     }
     const unknown_size: []u8 = array;
     for (unknown_size) |item| {
-        %%io.stdout.print_u64(item);
+        %%io.stdout.printInt(@typeOf(item), item);
         %%io.stdout.printf("\n");
     }
     for (unknown_size) |item, index| {
-        %%io.stdout.print_u64(index);
+        %%io.stdout.printInt(@typeOf(index), index);
         %%io.stdout.printf("\n");
     }
 }