diff --git a/CMakeLists.txt b/CMakeLists.txt
index 03197a43c79dfbd1c4a2de34c359b70c5bf5d160..380c617e172c06195096deb9045887c9dfbfde99 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -311,7 +311,7 @@ install(FILES "${CMAKE_SOURCE_DIR}/std/special/bootstrap.zig" DESTINATION "${ZIG
 install(FILES "${CMAKE_SOURCE_DIR}/std/special/build_file_template.zig" DESTINATION "${ZIG_STD_DEST}/special")
 install(FILES "${CMAKE_SOURCE_DIR}/std/special/build_runner.zig" DESTINATION "${ZIG_STD_DEST}/special")
 install(FILES "${CMAKE_SOURCE_DIR}/std/special/builtin.zig" DESTINATION "${ZIG_STD_DEST}/special")
-install(FILES "${CMAKE_SOURCE_DIR}/std/special/compiler_rt.zig" DESTINATION "${ZIG_STD_DEST}/special")
+install(FILES "${CMAKE_SOURCE_DIR}/std/special/compiler_rt/index.zig" DESTINATION "${ZIG_STD_DEST}/special/compiler_rt")
 install(FILES "${CMAKE_SOURCE_DIR}/std/special/test_runner.zig" DESTINATION "${ZIG_STD_DEST}/special")
 install(FILES "${CMAKE_SOURCE_DIR}/std/special/zigrt.zig" DESTINATION "${ZIG_STD_DEST}/special")
 
diff --git a/src/link.cpp b/src/link.cpp
index 1e44d908fb0abf94a15324ed9a29ffd75c0ef698..f03108440973b507ba97fa2bfea9037c362b2525 100644
--- a/src/link.cpp
+++ b/src/link.cpp
@@ -31,11 +31,7 @@ static const char *get_libc_static_file(CodeGen *g, const char *file) {
     return buf_ptr(out_buf);
 }
 
-static Buf *build_o(CodeGen *parent_gen, const char *oname) {
-    Buf *source_basename = buf_sprintf("%s.zig", oname);
-    Buf *full_path = buf_alloc();
-    os_path_join(parent_gen->zig_std_special_dir, source_basename, full_path);
-
+static Buf *build_o_raw(CodeGen *parent_gen, const char *oname, Buf *full_path) {
     ZigTarget *child_target = parent_gen->is_native_target ? nullptr : &parent_gen->zig_target;
     CodeGen *child_gen = codegen_create(full_path, child_target, OutTypeObj, parent_gen->build_mode);
 
@@ -65,6 +61,23 @@ static Buf *build_o(CodeGen *parent_gen, const char *oname) {
     return output_path;
 }
 
+static Buf *build_o(CodeGen *parent_gen, const char *oname) {
+    Buf *source_basename = buf_sprintf("%s.zig", oname);
+    Buf *full_path = buf_alloc();
+    os_path_join(parent_gen->zig_std_special_dir, source_basename, full_path);
+
+    return build_o_raw(parent_gen, oname, full_path);
+}
+
+static Buf *build_compiler_rt(CodeGen *parent_gen) {
+    Buf *dir_path = buf_alloc();
+    os_path_join(parent_gen->zig_std_special_dir, buf_create_from_str("compiler_rt"), dir_path);
+    Buf *full_path = buf_alloc();
+    os_path_join(dir_path, buf_create_from_str("index.zig"), full_path);
+
+    return build_o_raw(parent_gen, "compiler_rt", full_path);
+}
+
 static const char *get_exe_file_extension(CodeGen *g) {
     if (g->zig_target.os == ZigLLVM_Win32) {
         return ".exe";
@@ -263,7 +276,7 @@ static void construct_linker_job_elf(LinkJob *lj) {
         Buf *builtin_o_path = build_o(g, "builtin");
         lj->args.append(buf_ptr(builtin_o_path));
 
-        Buf *compiler_rt_o_path = build_o(g, "compiler_rt");
+        Buf *compiler_rt_o_path = build_compiler_rt(g);
         lj->args.append(buf_ptr(compiler_rt_o_path));
     }
 
@@ -401,7 +414,7 @@ static void construct_linker_job_coff(LinkJob *lj) {
         Buf *builtin_o_path = build_o(g, "builtin");
         lj->args.append(buf_ptr(builtin_o_path));
 
-        Buf *compiler_rt_o_path = build_o(g, "compiler_rt");
+        Buf *compiler_rt_o_path = build_compiler_rt(g);
         lj->args.append(buf_ptr(compiler_rt_o_path));
     }
 
diff --git a/std/special/compiler_rt.zig b/std/special/compiler_rt.zig
deleted file mode 100644
index e4fc338e824d496495e8db32f22f09c6d45c2442..0000000000000000000000000000000000000000
--- a/std/special/compiler_rt.zig
+++ /dev/null
@@ -1,507 +0,0 @@
-const builtin = @import("builtin");
-
-const CHAR_BIT = 8;
-const du_int = u64;
-const di_int = i64;
-const si_int = c_int;
-const su_int = c_uint;
-
-const udwords = [2]su_int;
-const low = if (builtin.is_big_endian) 1 else 0;
-const high = 1 - low;
-
-export fn __udivdi3(a: du_int, b: du_int) -> du_int {
-    @setDebugSafety(this, false);
-    return __udivmoddi4(a, b, null);
-}
-
-fn du_int_to_udwords(x: du_int) -> udwords {
-    @setDebugSafety(this, false);
-    return *@ptrCast(&udwords, &x);
-}
-
-export fn __udivmoddi4(a: du_int, b: du_int, maybe_rem: ?&du_int) -> du_int {
-    @setDebugSafety(this, false);
-
-    const n_uword_bits = @sizeOf(su_int) * CHAR_BIT;
-    const n_udword_bits = @sizeOf(du_int) * CHAR_BIT;
-    var n = du_int_to_udwords(a);
-    var d = du_int_to_udwords(b);
-    var q: udwords = undefined;
-    var r: udwords = undefined;
-    var sr: c_uint = undefined;
-    // special cases, X is unknown, K != 0
-    if (n[high] == 0) {
-        if (d[high] == 0) {
-            // 0 X
-            // ---
-            // 0 X
-            if (maybe_rem) |rem| {
-                *rem = n[low] % d[low];
-            }
-            return n[low] / d[low];
-        }
-        // 0 X
-        // ---
-        // K X
-        if (maybe_rem) |rem| {
-            *rem = n[low];
-        }
-        return 0;
-    }
-    // n[high] != 0
-    if (d[low] == 0) {
-        if (d[high] == 0) {
-            // K X
-            // ---
-            // 0 0
-            if (maybe_rem) |rem| {
-                *rem = n[high] % d[low];
-            }
-            return n[high] / d[low];
-        }
-        // d[high] != 0
-        if (n[low] == 0) {
-            // K 0
-            // ---
-            // K 0
-            if (maybe_rem) |rem| {
-                r[high] = n[high] % d[high];
-                r[low] = 0;
-                *rem = *@ptrCast(&du_int, &r[0]);
-            }
-            return n[high] / d[high];
-        }
-        // K K
-        // ---
-        // K 0
-        // if d is a power of 2
-        if ((d[high] & (d[high] - 1)) == 0) {
-            if (maybe_rem) |rem| {
-                r[low] = n[low];
-                r[high] = n[high] & (d[high] - 1);
-                *rem = *@ptrCast(&du_int, &r[0]);
-            }
-            return n[high] >> @ctz(d[high]);
-        }
-        // K K
-        // ---
-        // K 0
-        sr = @clz(su_int(d[high])) - @clz(su_int(n[high]));
-        // 0 <= sr <= n_uword_bits - 2 or sr large
-        if (sr > n_uword_bits - 2) {
-            if (maybe_rem) |rem| {
-                *rem = *@ptrCast(&du_int, &n[0]);
-            }
-            return 0;
-        }
-        sr += 1;
-        // 1 <= sr <= n_uword_bits - 1
-        // q.all = n.all << (n_udword_bits - sr);
-        q[low] = 0;
-        q[high] = n[low] << (n_uword_bits - sr);
-        // r.all = n.all >> sr;
-        r[high] = n[high] >> sr;
-        r[low] = (n[high] << (n_uword_bits - sr)) | (n[low] >> sr);
-    } else {
-        // d[low] != 0
-        if (d[high] == 0) {
-            // K X
-            // ---
-            // 0 K
-            // if d is a power of 2
-            if ((d[low] & (d[low] - 1)) == 0) {
-                if (maybe_rem) |rem| {
-                    *rem = n[low] & (d[low] - 1);
-                }
-                if (d[low] == 1) {
-                    return *@ptrCast(&du_int, &n[0]);
-                }
-                sr = @ctz(d[low]);
-                q[high] = n[high] >> sr;
-                q[low] = (n[high] << (n_uword_bits - sr)) | (n[low] >> sr);
-                return *@ptrCast(&du_int, &q[0]);
-            }
-            // K X
-            // ---
-            // 0 K
-            sr = 1 + n_uword_bits + @clz(su_int(d[low])) - @clz(su_int(n[high]));
-            // 2 <= sr <= n_udword_bits - 1
-            // q.all = n.all << (n_udword_bits - sr);
-            // r.all = n.all >> sr;
-            if (sr == n_uword_bits) {
-                q[low] = 0;
-                q[high] = n[low];
-                r[high] = 0;
-                r[low] = n[high];
-            } else if (sr < n_uword_bits) {
-                // 2 <= sr <= n_uword_bits - 1
-                q[low] = 0;
-                q[high] = n[low] << (n_uword_bits - sr);
-                r[high] = n[high] >> sr;
-                r[low] = (n[high] << (n_uword_bits - sr)) | (n[low] >> sr);
-            } else {
-                // n_uword_bits + 1 <= sr <= n_udword_bits - 1
-                q[low] = n[low] << (n_udword_bits - sr);
-                q[high] = (n[high] << (n_udword_bits - sr)) |
-                    (n[low] >> (sr - n_uword_bits));
-                r[high] = 0;
-                r[low] = n[high] >> (sr - n_uword_bits);
-            }
-        } else {
-            // K X
-            // ---
-            // K K
-            sr = @clz(su_int(d[high])) - @clz(su_int(n[high]));
-            // 0 <= sr <= n_uword_bits - 1 or sr large
-            if (sr > n_uword_bits - 1) {
-                if (maybe_rem) |rem| {
-                    *rem = *@ptrCast(&du_int, &n[0]);
-                }
-                return 0;
-            }
-            sr += 1;
-            // 1 <= sr <= n_uword_bits
-            //  q.all = n.all << (n_udword_bits - sr);
-            q[low] = 0;
-            if (sr == n_uword_bits) {
-                q[high] = n[low];
-                r[high] = 0;
-                r[low] = n[high];
-            } else {
-                q[high] = n[low] << (n_uword_bits - sr);
-                r[high] = n[high] >> sr;
-                r[low] = (n[high] << (n_uword_bits - sr)) | (n[low] >> sr);
-            }
-        }
-    }
-    // Not a special case
-    // q and r are initialized with:
-    // q.all = n.all << (n_udword_bits - sr);
-    // r.all = n.all >> sr;
-    // 1 <= sr <= n_udword_bits - 1
-    var carry: su_int = 0;
-    while (sr > 0) {
-        // r:q = ((r:q)  << 1) | carry
-        r[high] = (r[high] << 1) | (r[low]  >> (n_uword_bits - 1));
-        r[low]  = (r[low]  << 1) | (q[high] >> (n_uword_bits - 1));
-        q[high] = (q[high] << 1) | (q[low]  >> (n_uword_bits - 1));
-        q[low]  = (q[low]  << 1) | carry;
-        // carry = 0;
-        // if (r.all >= d.all)
-        // {
-        //      r.all -= d.all;
-        //      carry = 1;
-        // }
-        const s: di_int = (di_int)(*@ptrCast(&du_int, &d[0]) - *@ptrCast(&du_int, &r[0]) - 1) >> (n_udword_bits - 1);
-        carry = su_int(s & 1);
-        *@ptrCast(&du_int, &r[0]) -= *@ptrCast(&du_int, &d[0]) & u64(s);
-
-        sr -= 1;
-    }
-    *@ptrCast(&du_int, &q[0]) = (*@ptrCast(&du_int, &q[0]) << 1) | u64(carry);
-    if (maybe_rem) |rem| {
-        *rem = *@ptrCast(&du_int, &r[0]);
-    }
-    return *@ptrCast(&du_int, &q[0]);
-}
-
-export fn __umoddi3(a: du_int, b: du_int) -> du_int {
-    @setDebugSafety(this, false);
-
-    var r: du_int = undefined;
-    _ = __udivmoddi4(a, b, &r);
-    return r;
-}
-
-fn isArmArch() -> bool {
-    return switch (builtin.arch) {
-        builtin.Arch.armv8_2a,
-        builtin.Arch.armv8_1a,
-        builtin.Arch.armv8,
-        builtin.Arch.armv8m_baseline,
-        builtin.Arch.armv8m_mainline,
-        builtin.Arch.armv7,
-        builtin.Arch.armv7em,
-        builtin.Arch.armv7m,
-        builtin.Arch.armv7s,
-        builtin.Arch.armv7k,
-        builtin.Arch.armv6,
-        builtin.Arch.armv6m,
-        builtin.Arch.armv6k,
-        builtin.Arch.armv6t2,
-        builtin.Arch.armv5,
-        builtin.Arch.armv5te,
-        builtin.Arch.armv4t,
-        builtin.Arch.armeb => true,
-        else => false,
-    };
-}
-
-export nakedcc fn __aeabi_uidivmod() {
-    @setDebugSafety(this, false);
-
-    if (comptime isArmArch()) {
-        asm volatile (
-            \\ push    { lr }
-            \\ sub     sp, sp, #4
-            \\ mov     r2, sp
-            \\ bl      __udivmodsi4
-            \\ ldr     r1, [sp]
-            \\ add     sp, sp, #4
-            \\ pop     { pc }
-        ::: "r2", "r1");
-        unreachable;
-    }
-
-    @setGlobalLinkage(__aeabi_uidivmod, builtin.GlobalLinkage.Internal);
-}
-
-export fn __udivmodsi4(a: su_int, b: su_int, rem: &su_int) -> su_int {
-    @setDebugSafety(this, false);
-
-    const d = __udivsi3(a, b);
-    *rem = su_int(si_int(a) -% (si_int(d) * si_int(b)));
-    return d;
-}
-
-
-// TODO make this an alias instead of an extra function call
-// https://github.com/andrewrk/zig/issues/256
-
-export fn __aeabi_uidiv(n: su_int, d: su_int) -> su_int {
-    @setDebugSafety(this, false);
-
-    return __udivsi3(n, d);
-}
-
-export fn __udivsi3(n: su_int, d: su_int) -> su_int {
-    @setDebugSafety(this, false);
-
-    const n_uword_bits: c_uint = @sizeOf(su_int) * CHAR_BIT;
-    // special cases
-    if (d == 0)
-        return 0; // ?!
-    if (n == 0)
-        return 0;
-    var sr: c_uint = @clz(d) - @clz(n);
-    // 0 <= sr <= n_uword_bits - 1 or sr large
-    if (sr > n_uword_bits - 1)  // d > r
-        return 0;
-    if (sr == n_uword_bits - 1)  // d == 1
-        return n;
-    sr += 1;
-    // 1 <= sr <= n_uword_bits - 1
-    // Not a special case
-    var q: su_int = n << (n_uword_bits - sr);
-    var r: su_int = n >> sr;
-    var carry: su_int = 0;
-    while (sr > 0) : (sr -= 1) {
-        // r:q = ((r:q)  << 1) | carry
-        r = (r << 1) | (q >> (n_uword_bits - 1));
-        q = (q << 1) | carry;
-        // carry = 0;
-        // if (r.all >= d.all)
-        // {
-        //      r.all -= d.all;
-        //      carry = 1;
-        // }
-        const s = si_int(d - r - 1) >> si_int(n_uword_bits - 1);
-        carry = su_int(s & 1);
-        r -= d & su_int(s);
-    }
-    q = (q << 1) | carry;
-    return q;
-}
-
-test "test_umoddi3" {
-    test_one_umoddi3(0, 1, 0);
-    test_one_umoddi3(2, 1, 0);
-    test_one_umoddi3(0x8000000000000000, 1, 0x0);
-    test_one_umoddi3(0x8000000000000000, 2, 0x0);
-    test_one_umoddi3(0xFFFFFFFFFFFFFFFF, 2, 0x1);
-}
-
-fn test_one_umoddi3(a: du_int, b: du_int, expected_r: du_int) {
-    const r = __umoddi3(a, b);
-    assert(r == expected_r);
-}
-
-test "test_udivmoddi4" {
-    const cases = [][4]du_int {
-        []du_int{0x0000000000000000, 0x0000000000000001, 0x0000000000000000, 0x0000000000000000},
-        []du_int{0x0000000080000000, 0x0000000100000001, 0x0000000000000000, 0x0000000080000000},
-        []du_int{0x7FFFFFFF00000001, 0x0000000000000001, 0x7FFFFFFF00000001, 0x0000000000000000},
-        []du_int{0x7FFFFFFF7FFFFFFF, 0xFFFFFFFFFFFFFFFF, 0x0000000000000000, 0x7FFFFFFF7FFFFFFF},
-        []du_int{0x8000000000000002, 0xFFFFFFFFFFFFFFFE, 0x0000000000000000, 0x8000000000000002},
-        []du_int{0x80000000FFFFFFFD, 0xFFFFFFFFFFFFFFFD, 0x0000000000000000, 0x80000000FFFFFFFD},
-        []du_int{0xFFFFFFFD00000010, 0xFFFFFFFF80000000, 0x0000000000000000, 0xFFFFFFFD00000010},
-        []du_int{0xFFFFFFFDFFFFFFFF, 0xFFFFFFFF7FFFFFFF, 0x0000000000000000, 0xFFFFFFFDFFFFFFFF},
-        []du_int{0xFFFFFFFE0747AE14, 0xFFFFFFFF0747AE14, 0x0000000000000000, 0xFFFFFFFE0747AE14},
-        []du_int{0xFFFFFFFF00000001, 0xFFFFFFFF078644FA, 0x0000000000000000, 0xFFFFFFFF00000001},
-        []du_int{0xFFFFFFFF80000000, 0xFFFFFFFF00000010, 0x0000000000000001, 0x000000007FFFFFF0},
-        []du_int{0xFFFFFFFFFFFFFFFF, 0xFFFFFFFFFFFFFFFF, 0x0000000000000001, 0x0000000000000000},
-    };
-
-    for (cases) |case| {
-        test_one_udivmoddi4(case[0], case[1], case[2], case[3]);
-    }
-}
-
-fn test_one_udivmoddi4(a: du_int, b: du_int, expected_q: du_int, expected_r: du_int) {
-    var r: du_int = undefined;
-    const q = __udivmoddi4(a, b, &r);
-    assert(q == expected_q);
-    assert(r == expected_r);
-}
-
-test "test_udivsi3" {
-    const cases = [][3]su_int {
-        []su_int{0x00000000, 0x00000001, 0x00000000},
-        []su_int{0x00000000, 0x00000002, 0x00000000},
-        []su_int{0x00000000, 0x00000003, 0x00000000},
-        []su_int{0x00000000, 0x00000010, 0x00000000},
-        []su_int{0x00000000, 0x078644FA, 0x00000000},
-        []su_int{0x00000000, 0x0747AE14, 0x00000000},
-        []su_int{0x00000000, 0x7FFFFFFF, 0x00000000},
-        []su_int{0x00000000, 0x80000000, 0x00000000},
-        []su_int{0x00000000, 0xFFFFFFFD, 0x00000000},
-        []su_int{0x00000000, 0xFFFFFFFE, 0x00000000},
-        []su_int{0x00000000, 0xFFFFFFFF, 0x00000000},
-        []su_int{0x00000001, 0x00000001, 0x00000001},
-        []su_int{0x00000001, 0x00000002, 0x00000000},
-        []su_int{0x00000001, 0x00000003, 0x00000000},
-        []su_int{0x00000001, 0x00000010, 0x00000000},
-        []su_int{0x00000001, 0x078644FA, 0x00000000},
-        []su_int{0x00000001, 0x0747AE14, 0x00000000},
-        []su_int{0x00000001, 0x7FFFFFFF, 0x00000000},
-        []su_int{0x00000001, 0x80000000, 0x00000000},
-        []su_int{0x00000001, 0xFFFFFFFD, 0x00000000},
-        []su_int{0x00000001, 0xFFFFFFFE, 0x00000000},
-        []su_int{0x00000001, 0xFFFFFFFF, 0x00000000},
-        []su_int{0x00000002, 0x00000001, 0x00000002},
-        []su_int{0x00000002, 0x00000002, 0x00000001},
-        []su_int{0x00000002, 0x00000003, 0x00000000},
-        []su_int{0x00000002, 0x00000010, 0x00000000},
-        []su_int{0x00000002, 0x078644FA, 0x00000000},
-        []su_int{0x00000002, 0x0747AE14, 0x00000000},
-        []su_int{0x00000002, 0x7FFFFFFF, 0x00000000},
-        []su_int{0x00000002, 0x80000000, 0x00000000},
-        []su_int{0x00000002, 0xFFFFFFFD, 0x00000000},
-        []su_int{0x00000002, 0xFFFFFFFE, 0x00000000},
-        []su_int{0x00000002, 0xFFFFFFFF, 0x00000000},
-        []su_int{0x00000003, 0x00000001, 0x00000003},
-        []su_int{0x00000003, 0x00000002, 0x00000001},
-        []su_int{0x00000003, 0x00000003, 0x00000001},
-        []su_int{0x00000003, 0x00000010, 0x00000000},
-        []su_int{0x00000003, 0x078644FA, 0x00000000},
-        []su_int{0x00000003, 0x0747AE14, 0x00000000},
-        []su_int{0x00000003, 0x7FFFFFFF, 0x00000000},
-        []su_int{0x00000003, 0x80000000, 0x00000000},
-        []su_int{0x00000003, 0xFFFFFFFD, 0x00000000},
-        []su_int{0x00000003, 0xFFFFFFFE, 0x00000000},
-        []su_int{0x00000003, 0xFFFFFFFF, 0x00000000},
-        []su_int{0x00000010, 0x00000001, 0x00000010},
-        []su_int{0x00000010, 0x00000002, 0x00000008},
-        []su_int{0x00000010, 0x00000003, 0x00000005},
-        []su_int{0x00000010, 0x00000010, 0x00000001},
-        []su_int{0x00000010, 0x078644FA, 0x00000000},
-        []su_int{0x00000010, 0x0747AE14, 0x00000000},
-        []su_int{0x00000010, 0x7FFFFFFF, 0x00000000},
-        []su_int{0x00000010, 0x80000000, 0x00000000},
-        []su_int{0x00000010, 0xFFFFFFFD, 0x00000000},
-        []su_int{0x00000010, 0xFFFFFFFE, 0x00000000},
-        []su_int{0x00000010, 0xFFFFFFFF, 0x00000000},
-        []su_int{0x078644FA, 0x00000001, 0x078644FA},
-        []su_int{0x078644FA, 0x00000002, 0x03C3227D},
-        []su_int{0x078644FA, 0x00000003, 0x028216FE},
-        []su_int{0x078644FA, 0x00000010, 0x0078644F},
-        []su_int{0x078644FA, 0x078644FA, 0x00000001},
-        []su_int{0x078644FA, 0x0747AE14, 0x00000001},
-        []su_int{0x078644FA, 0x7FFFFFFF, 0x00000000},
-        []su_int{0x078644FA, 0x80000000, 0x00000000},
-        []su_int{0x078644FA, 0xFFFFFFFD, 0x00000000},
-        []su_int{0x078644FA, 0xFFFFFFFE, 0x00000000},
-        []su_int{0x078644FA, 0xFFFFFFFF, 0x00000000},
-        []su_int{0x0747AE14, 0x00000001, 0x0747AE14},
-        []su_int{0x0747AE14, 0x00000002, 0x03A3D70A},
-        []su_int{0x0747AE14, 0x00000003, 0x026D3A06},
-        []su_int{0x0747AE14, 0x00000010, 0x00747AE1},
-        []su_int{0x0747AE14, 0x078644FA, 0x00000000},
-        []su_int{0x0747AE14, 0x0747AE14, 0x00000001},
-        []su_int{0x0747AE14, 0x7FFFFFFF, 0x00000000},
-        []su_int{0x0747AE14, 0x80000000, 0x00000000},
-        []su_int{0x0747AE14, 0xFFFFFFFD, 0x00000000},
-        []su_int{0x0747AE14, 0xFFFFFFFE, 0x00000000},
-        []su_int{0x0747AE14, 0xFFFFFFFF, 0x00000000},
-        []su_int{0x7FFFFFFF, 0x00000001, 0x7FFFFFFF},
-        []su_int{0x7FFFFFFF, 0x00000002, 0x3FFFFFFF},
-        []su_int{0x7FFFFFFF, 0x00000003, 0x2AAAAAAA},
-        []su_int{0x7FFFFFFF, 0x00000010, 0x07FFFFFF},
-        []su_int{0x7FFFFFFF, 0x078644FA, 0x00000011},
-        []su_int{0x7FFFFFFF, 0x0747AE14, 0x00000011},
-        []su_int{0x7FFFFFFF, 0x7FFFFFFF, 0x00000001},
-        []su_int{0x7FFFFFFF, 0x80000000, 0x00000000},
-        []su_int{0x7FFFFFFF, 0xFFFFFFFD, 0x00000000},
-        []su_int{0x7FFFFFFF, 0xFFFFFFFE, 0x00000000},
-        []su_int{0x7FFFFFFF, 0xFFFFFFFF, 0x00000000},
-        []su_int{0x80000000, 0x00000001, 0x80000000},
-        []su_int{0x80000000, 0x00000002, 0x40000000},
-        []su_int{0x80000000, 0x00000003, 0x2AAAAAAA},
-        []su_int{0x80000000, 0x00000010, 0x08000000},
-        []su_int{0x80000000, 0x078644FA, 0x00000011},
-        []su_int{0x80000000, 0x0747AE14, 0x00000011},
-        []su_int{0x80000000, 0x7FFFFFFF, 0x00000001},
-        []su_int{0x80000000, 0x80000000, 0x00000001},
-        []su_int{0x80000000, 0xFFFFFFFD, 0x00000000},
-        []su_int{0x80000000, 0xFFFFFFFE, 0x00000000},
-        []su_int{0x80000000, 0xFFFFFFFF, 0x00000000},
-        []su_int{0xFFFFFFFD, 0x00000001, 0xFFFFFFFD},
-        []su_int{0xFFFFFFFD, 0x00000002, 0x7FFFFFFE},
-        []su_int{0xFFFFFFFD, 0x00000003, 0x55555554},
-        []su_int{0xFFFFFFFD, 0x00000010, 0x0FFFFFFF},
-        []su_int{0xFFFFFFFD, 0x078644FA, 0x00000022},
-        []su_int{0xFFFFFFFD, 0x0747AE14, 0x00000023},
-        []su_int{0xFFFFFFFD, 0x7FFFFFFF, 0x00000001},
-        []su_int{0xFFFFFFFD, 0x80000000, 0x00000001},
-        []su_int{0xFFFFFFFD, 0xFFFFFFFD, 0x00000001},
-        []su_int{0xFFFFFFFD, 0xFFFFFFFE, 0x00000000},
-        []su_int{0xFFFFFFFD, 0xFFFFFFFF, 0x00000000},
-        []su_int{0xFFFFFFFE, 0x00000001, 0xFFFFFFFE},
-        []su_int{0xFFFFFFFE, 0x00000002, 0x7FFFFFFF},
-        []su_int{0xFFFFFFFE, 0x00000003, 0x55555554},
-        []su_int{0xFFFFFFFE, 0x00000010, 0x0FFFFFFF},
-        []su_int{0xFFFFFFFE, 0x078644FA, 0x00000022},
-        []su_int{0xFFFFFFFE, 0x0747AE14, 0x00000023},
-        []su_int{0xFFFFFFFE, 0x7FFFFFFF, 0x00000002},
-        []su_int{0xFFFFFFFE, 0x80000000, 0x00000001},
-        []su_int{0xFFFFFFFE, 0xFFFFFFFD, 0x00000001},
-        []su_int{0xFFFFFFFE, 0xFFFFFFFE, 0x00000001},
-        []su_int{0xFFFFFFFE, 0xFFFFFFFF, 0x00000000},
-        []su_int{0xFFFFFFFF, 0x00000001, 0xFFFFFFFF},
-        []su_int{0xFFFFFFFF, 0x00000002, 0x7FFFFFFF},
-        []su_int{0xFFFFFFFF, 0x00000003, 0x55555555},
-        []su_int{0xFFFFFFFF, 0x00000010, 0x0FFFFFFF},
-        []su_int{0xFFFFFFFF, 0x078644FA, 0x00000022},
-        []su_int{0xFFFFFFFF, 0x0747AE14, 0x00000023},
-        []su_int{0xFFFFFFFF, 0x7FFFFFFF, 0x00000002},
-        []su_int{0xFFFFFFFF, 0x80000000, 0x00000001},
-        []su_int{0xFFFFFFFF, 0xFFFFFFFD, 0x00000001},
-        []su_int{0xFFFFFFFF, 0xFFFFFFFE, 0x00000001},
-        []su_int{0xFFFFFFFF, 0xFFFFFFFF, 0x00000001},
-    };
-
-    for (cases) |case| {
-        test_one_udivsi3(case[0], case[1], case[2]);
-    }
-}
-
-fn test_one_udivsi3(a: su_int, b: su_int, expected_q: su_int) {
-    const q: su_int = __udivsi3(a, b);
-    assert(q == expected_q);
-}
-
-
-fn assert(ok: bool) {
-    if (!ok) unreachable;
-}
diff --git a/std/special/compiler_rt/index.zig b/std/special/compiler_rt/index.zig
new file mode 100644
index 0000000000000000000000000000000000000000..e4fc338e824d496495e8db32f22f09c6d45c2442
--- /dev/null
+++ b/std/special/compiler_rt/index.zig
@@ -0,0 +1,507 @@
+const builtin = @import("builtin");
+
+const CHAR_BIT = 8;
+const du_int = u64;
+const di_int = i64;
+const si_int = c_int;
+const su_int = c_uint;
+
+const udwords = [2]su_int;
+const low = if (builtin.is_big_endian) 1 else 0;
+const high = 1 - low;
+
+export fn __udivdi3(a: du_int, b: du_int) -> du_int {
+    @setDebugSafety(this, false);
+    return __udivmoddi4(a, b, null);
+}
+
+fn du_int_to_udwords(x: du_int) -> udwords {
+    @setDebugSafety(this, false);
+    return *@ptrCast(&udwords, &x);
+}
+
+export fn __udivmoddi4(a: du_int, b: du_int, maybe_rem: ?&du_int) -> du_int {
+    @setDebugSafety(this, false);
+
+    const n_uword_bits = @sizeOf(su_int) * CHAR_BIT;
+    const n_udword_bits = @sizeOf(du_int) * CHAR_BIT;
+    var n = du_int_to_udwords(a);
+    var d = du_int_to_udwords(b);
+    var q: udwords = undefined;
+    var r: udwords = undefined;
+    var sr: c_uint = undefined;
+    // special cases, X is unknown, K != 0
+    if (n[high] == 0) {
+        if (d[high] == 0) {
+            // 0 X
+            // ---
+            // 0 X
+            if (maybe_rem) |rem| {
+                *rem = n[low] % d[low];
+            }
+            return n[low] / d[low];
+        }
+        // 0 X
+        // ---
+        // K X
+        if (maybe_rem) |rem| {
+            *rem = n[low];
+        }
+        return 0;
+    }
+    // n[high] != 0
+    if (d[low] == 0) {
+        if (d[high] == 0) {
+            // K X
+            // ---
+            // 0 0
+            if (maybe_rem) |rem| {
+                *rem = n[high] % d[low];
+            }
+            return n[high] / d[low];
+        }
+        // d[high] != 0
+        if (n[low] == 0) {
+            // K 0
+            // ---
+            // K 0
+            if (maybe_rem) |rem| {
+                r[high] = n[high] % d[high];
+                r[low] = 0;
+                *rem = *@ptrCast(&du_int, &r[0]);
+            }
+            return n[high] / d[high];
+        }
+        // K K
+        // ---
+        // K 0
+        // if d is a power of 2
+        if ((d[high] & (d[high] - 1)) == 0) {
+            if (maybe_rem) |rem| {
+                r[low] = n[low];
+                r[high] = n[high] & (d[high] - 1);
+                *rem = *@ptrCast(&du_int, &r[0]);
+            }
+            return n[high] >> @ctz(d[high]);
+        }
+        // K K
+        // ---
+        // K 0
+        sr = @clz(su_int(d[high])) - @clz(su_int(n[high]));
+        // 0 <= sr <= n_uword_bits - 2 or sr large
+        if (sr > n_uword_bits - 2) {
+            if (maybe_rem) |rem| {
+                *rem = *@ptrCast(&du_int, &n[0]);
+            }
+            return 0;
+        }
+        sr += 1;
+        // 1 <= sr <= n_uword_bits - 1
+        // q.all = n.all << (n_udword_bits - sr);
+        q[low] = 0;
+        q[high] = n[low] << (n_uword_bits - sr);
+        // r.all = n.all >> sr;
+        r[high] = n[high] >> sr;
+        r[low] = (n[high] << (n_uword_bits - sr)) | (n[low] >> sr);
+    } else {
+        // d[low] != 0
+        if (d[high] == 0) {
+            // K X
+            // ---
+            // 0 K
+            // if d is a power of 2
+            if ((d[low] & (d[low] - 1)) == 0) {
+                if (maybe_rem) |rem| {
+                    *rem = n[low] & (d[low] - 1);
+                }
+                if (d[low] == 1) {
+                    return *@ptrCast(&du_int, &n[0]);
+                }
+                sr = @ctz(d[low]);
+                q[high] = n[high] >> sr;
+                q[low] = (n[high] << (n_uword_bits - sr)) | (n[low] >> sr);
+                return *@ptrCast(&du_int, &q[0]);
+            }
+            // K X
+            // ---
+            // 0 K
+            sr = 1 + n_uword_bits + @clz(su_int(d[low])) - @clz(su_int(n[high]));
+            // 2 <= sr <= n_udword_bits - 1
+            // q.all = n.all << (n_udword_bits - sr);
+            // r.all = n.all >> sr;
+            if (sr == n_uword_bits) {
+                q[low] = 0;
+                q[high] = n[low];
+                r[high] = 0;
+                r[low] = n[high];
+            } else if (sr < n_uword_bits) {
+                // 2 <= sr <= n_uword_bits - 1
+                q[low] = 0;
+                q[high] = n[low] << (n_uword_bits - sr);
+                r[high] = n[high] >> sr;
+                r[low] = (n[high] << (n_uword_bits - sr)) | (n[low] >> sr);
+            } else {
+                // n_uword_bits + 1 <= sr <= n_udword_bits - 1
+                q[low] = n[low] << (n_udword_bits - sr);
+                q[high] = (n[high] << (n_udword_bits - sr)) |
+                    (n[low] >> (sr - n_uword_bits));
+                r[high] = 0;
+                r[low] = n[high] >> (sr - n_uword_bits);
+            }
+        } else {
+            // K X
+            // ---
+            // K K
+            sr = @clz(su_int(d[high])) - @clz(su_int(n[high]));
+            // 0 <= sr <= n_uword_bits - 1 or sr large
+            if (sr > n_uword_bits - 1) {
+                if (maybe_rem) |rem| {
+                    *rem = *@ptrCast(&du_int, &n[0]);
+                }
+                return 0;
+            }
+            sr += 1;
+            // 1 <= sr <= n_uword_bits
+            //  q.all = n.all << (n_udword_bits - sr);
+            q[low] = 0;
+            if (sr == n_uword_bits) {
+                q[high] = n[low];
+                r[high] = 0;
+                r[low] = n[high];
+            } else {
+                q[high] = n[low] << (n_uword_bits - sr);
+                r[high] = n[high] >> sr;
+                r[low] = (n[high] << (n_uword_bits - sr)) | (n[low] >> sr);
+            }
+        }
+    }
+    // Not a special case
+    // q and r are initialized with:
+    // q.all = n.all << (n_udword_bits - sr);
+    // r.all = n.all >> sr;
+    // 1 <= sr <= n_udword_bits - 1
+    var carry: su_int = 0;
+    while (sr > 0) {
+        // r:q = ((r:q)  << 1) | carry
+        r[high] = (r[high] << 1) | (r[low]  >> (n_uword_bits - 1));
+        r[low]  = (r[low]  << 1) | (q[high] >> (n_uword_bits - 1));
+        q[high] = (q[high] << 1) | (q[low]  >> (n_uword_bits - 1));
+        q[low]  = (q[low]  << 1) | carry;
+        // carry = 0;
+        // if (r.all >= d.all)
+        // {
+        //      r.all -= d.all;
+        //      carry = 1;
+        // }
+        const s: di_int = (di_int)(*@ptrCast(&du_int, &d[0]) - *@ptrCast(&du_int, &r[0]) - 1) >> (n_udword_bits - 1);
+        carry = su_int(s & 1);
+        *@ptrCast(&du_int, &r[0]) -= *@ptrCast(&du_int, &d[0]) & u64(s);
+
+        sr -= 1;
+    }
+    *@ptrCast(&du_int, &q[0]) = (*@ptrCast(&du_int, &q[0]) << 1) | u64(carry);
+    if (maybe_rem) |rem| {
+        *rem = *@ptrCast(&du_int, &r[0]);
+    }
+    return *@ptrCast(&du_int, &q[0]);
+}
+
+export fn __umoddi3(a: du_int, b: du_int) -> du_int {
+    @setDebugSafety(this, false);
+
+    var r: du_int = undefined;
+    _ = __udivmoddi4(a, b, &r);
+    return r;
+}
+
+fn isArmArch() -> bool {
+    return switch (builtin.arch) {
+        builtin.Arch.armv8_2a,
+        builtin.Arch.armv8_1a,
+        builtin.Arch.armv8,
+        builtin.Arch.armv8m_baseline,
+        builtin.Arch.armv8m_mainline,
+        builtin.Arch.armv7,
+        builtin.Arch.armv7em,
+        builtin.Arch.armv7m,
+        builtin.Arch.armv7s,
+        builtin.Arch.armv7k,
+        builtin.Arch.armv6,
+        builtin.Arch.armv6m,
+        builtin.Arch.armv6k,
+        builtin.Arch.armv6t2,
+        builtin.Arch.armv5,
+        builtin.Arch.armv5te,
+        builtin.Arch.armv4t,
+        builtin.Arch.armeb => true,
+        else => false,
+    };
+}
+
+export nakedcc fn __aeabi_uidivmod() {
+    @setDebugSafety(this, false);
+
+    if (comptime isArmArch()) {
+        asm volatile (
+            \\ push    { lr }
+            \\ sub     sp, sp, #4
+            \\ mov     r2, sp
+            \\ bl      __udivmodsi4
+            \\ ldr     r1, [sp]
+            \\ add     sp, sp, #4
+            \\ pop     { pc }
+        ::: "r2", "r1");
+        unreachable;
+    }
+
+    @setGlobalLinkage(__aeabi_uidivmod, builtin.GlobalLinkage.Internal);
+}
+
+export fn __udivmodsi4(a: su_int, b: su_int, rem: &su_int) -> su_int {
+    @setDebugSafety(this, false);
+
+    const d = __udivsi3(a, b);
+    *rem = su_int(si_int(a) -% (si_int(d) * si_int(b)));
+    return d;
+}
+
+
+// TODO make this an alias instead of an extra function call
+// https://github.com/andrewrk/zig/issues/256
+
+export fn __aeabi_uidiv(n: su_int, d: su_int) -> su_int {
+    @setDebugSafety(this, false);
+
+    return __udivsi3(n, d);
+}
+
+export fn __udivsi3(n: su_int, d: su_int) -> su_int {
+    @setDebugSafety(this, false);
+
+    const n_uword_bits: c_uint = @sizeOf(su_int) * CHAR_BIT;
+    // special cases
+    if (d == 0)
+        return 0; // ?!
+    if (n == 0)
+        return 0;
+    var sr: c_uint = @clz(d) - @clz(n);
+    // 0 <= sr <= n_uword_bits - 1 or sr large
+    if (sr > n_uword_bits - 1)  // d > r
+        return 0;
+    if (sr == n_uword_bits - 1)  // d == 1
+        return n;
+    sr += 1;
+    // 1 <= sr <= n_uword_bits - 1
+    // Not a special case
+    var q: su_int = n << (n_uword_bits - sr);
+    var r: su_int = n >> sr;
+    var carry: su_int = 0;
+    while (sr > 0) : (sr -= 1) {
+        // r:q = ((r:q)  << 1) | carry
+        r = (r << 1) | (q >> (n_uword_bits - 1));
+        q = (q << 1) | carry;
+        // carry = 0;
+        // if (r.all >= d.all)
+        // {
+        //      r.all -= d.all;
+        //      carry = 1;
+        // }
+        const s = si_int(d - r - 1) >> si_int(n_uword_bits - 1);
+        carry = su_int(s & 1);
+        r -= d & su_int(s);
+    }
+    q = (q << 1) | carry;
+    return q;
+}
+
+test "test_umoddi3" {
+    test_one_umoddi3(0, 1, 0);
+    test_one_umoddi3(2, 1, 0);
+    test_one_umoddi3(0x8000000000000000, 1, 0x0);
+    test_one_umoddi3(0x8000000000000000, 2, 0x0);
+    test_one_umoddi3(0xFFFFFFFFFFFFFFFF, 2, 0x1);
+}
+
+fn test_one_umoddi3(a: du_int, b: du_int, expected_r: du_int) {
+    const r = __umoddi3(a, b);
+    assert(r == expected_r);
+}
+
+test "test_udivmoddi4" {
+    const cases = [][4]du_int {
+        []du_int{0x0000000000000000, 0x0000000000000001, 0x0000000000000000, 0x0000000000000000},
+        []du_int{0x0000000080000000, 0x0000000100000001, 0x0000000000000000, 0x0000000080000000},
+        []du_int{0x7FFFFFFF00000001, 0x0000000000000001, 0x7FFFFFFF00000001, 0x0000000000000000},
+        []du_int{0x7FFFFFFF7FFFFFFF, 0xFFFFFFFFFFFFFFFF, 0x0000000000000000, 0x7FFFFFFF7FFFFFFF},
+        []du_int{0x8000000000000002, 0xFFFFFFFFFFFFFFFE, 0x0000000000000000, 0x8000000000000002},
+        []du_int{0x80000000FFFFFFFD, 0xFFFFFFFFFFFFFFFD, 0x0000000000000000, 0x80000000FFFFFFFD},
+        []du_int{0xFFFFFFFD00000010, 0xFFFFFFFF80000000, 0x0000000000000000, 0xFFFFFFFD00000010},
+        []du_int{0xFFFFFFFDFFFFFFFF, 0xFFFFFFFF7FFFFFFF, 0x0000000000000000, 0xFFFFFFFDFFFFFFFF},
+        []du_int{0xFFFFFFFE0747AE14, 0xFFFFFFFF0747AE14, 0x0000000000000000, 0xFFFFFFFE0747AE14},
+        []du_int{0xFFFFFFFF00000001, 0xFFFFFFFF078644FA, 0x0000000000000000, 0xFFFFFFFF00000001},
+        []du_int{0xFFFFFFFF80000000, 0xFFFFFFFF00000010, 0x0000000000000001, 0x000000007FFFFFF0},
+        []du_int{0xFFFFFFFFFFFFFFFF, 0xFFFFFFFFFFFFFFFF, 0x0000000000000001, 0x0000000000000000},
+    };
+
+    for (cases) |case| {
+        test_one_udivmoddi4(case[0], case[1], case[2], case[3]);
+    }
+}
+
+fn test_one_udivmoddi4(a: du_int, b: du_int, expected_q: du_int, expected_r: du_int) {
+    var r: du_int = undefined;
+    const q = __udivmoddi4(a, b, &r);
+    assert(q == expected_q);
+    assert(r == expected_r);
+}
+
+test "test_udivsi3" {
+    const cases = [][3]su_int {
+        []su_int{0x00000000, 0x00000001, 0x00000000},
+        []su_int{0x00000000, 0x00000002, 0x00000000},
+        []su_int{0x00000000, 0x00000003, 0x00000000},
+        []su_int{0x00000000, 0x00000010, 0x00000000},
+        []su_int{0x00000000, 0x078644FA, 0x00000000},
+        []su_int{0x00000000, 0x0747AE14, 0x00000000},
+        []su_int{0x00000000, 0x7FFFFFFF, 0x00000000},
+        []su_int{0x00000000, 0x80000000, 0x00000000},
+        []su_int{0x00000000, 0xFFFFFFFD, 0x00000000},
+        []su_int{0x00000000, 0xFFFFFFFE, 0x00000000},
+        []su_int{0x00000000, 0xFFFFFFFF, 0x00000000},
+        []su_int{0x00000001, 0x00000001, 0x00000001},
+        []su_int{0x00000001, 0x00000002, 0x00000000},
+        []su_int{0x00000001, 0x00000003, 0x00000000},
+        []su_int{0x00000001, 0x00000010, 0x00000000},
+        []su_int{0x00000001, 0x078644FA, 0x00000000},
+        []su_int{0x00000001, 0x0747AE14, 0x00000000},
+        []su_int{0x00000001, 0x7FFFFFFF, 0x00000000},
+        []su_int{0x00000001, 0x80000000, 0x00000000},
+        []su_int{0x00000001, 0xFFFFFFFD, 0x00000000},
+        []su_int{0x00000001, 0xFFFFFFFE, 0x00000000},
+        []su_int{0x00000001, 0xFFFFFFFF, 0x00000000},
+        []su_int{0x00000002, 0x00000001, 0x00000002},
+        []su_int{0x00000002, 0x00000002, 0x00000001},
+        []su_int{0x00000002, 0x00000003, 0x00000000},
+        []su_int{0x00000002, 0x00000010, 0x00000000},
+        []su_int{0x00000002, 0x078644FA, 0x00000000},
+        []su_int{0x00000002, 0x0747AE14, 0x00000000},
+        []su_int{0x00000002, 0x7FFFFFFF, 0x00000000},
+        []su_int{0x00000002, 0x80000000, 0x00000000},
+        []su_int{0x00000002, 0xFFFFFFFD, 0x00000000},
+        []su_int{0x00000002, 0xFFFFFFFE, 0x00000000},
+        []su_int{0x00000002, 0xFFFFFFFF, 0x00000000},
+        []su_int{0x00000003, 0x00000001, 0x00000003},
+        []su_int{0x00000003, 0x00000002, 0x00000001},
+        []su_int{0x00000003, 0x00000003, 0x00000001},
+        []su_int{0x00000003, 0x00000010, 0x00000000},
+        []su_int{0x00000003, 0x078644FA, 0x00000000},
+        []su_int{0x00000003, 0x0747AE14, 0x00000000},
+        []su_int{0x00000003, 0x7FFFFFFF, 0x00000000},
+        []su_int{0x00000003, 0x80000000, 0x00000000},
+        []su_int{0x00000003, 0xFFFFFFFD, 0x00000000},
+        []su_int{0x00000003, 0xFFFFFFFE, 0x00000000},
+        []su_int{0x00000003, 0xFFFFFFFF, 0x00000000},
+        []su_int{0x00000010, 0x00000001, 0x00000010},
+        []su_int{0x00000010, 0x00000002, 0x00000008},
+        []su_int{0x00000010, 0x00000003, 0x00000005},
+        []su_int{0x00000010, 0x00000010, 0x00000001},
+        []su_int{0x00000010, 0x078644FA, 0x00000000},
+        []su_int{0x00000010, 0x0747AE14, 0x00000000},
+        []su_int{0x00000010, 0x7FFFFFFF, 0x00000000},
+        []su_int{0x00000010, 0x80000000, 0x00000000},
+        []su_int{0x00000010, 0xFFFFFFFD, 0x00000000},
+        []su_int{0x00000010, 0xFFFFFFFE, 0x00000000},
+        []su_int{0x00000010, 0xFFFFFFFF, 0x00000000},
+        []su_int{0x078644FA, 0x00000001, 0x078644FA},
+        []su_int{0x078644FA, 0x00000002, 0x03C3227D},
+        []su_int{0x078644FA, 0x00000003, 0x028216FE},
+        []su_int{0x078644FA, 0x00000010, 0x0078644F},
+        []su_int{0x078644FA, 0x078644FA, 0x00000001},
+        []su_int{0x078644FA, 0x0747AE14, 0x00000001},
+        []su_int{0x078644FA, 0x7FFFFFFF, 0x00000000},
+        []su_int{0x078644FA, 0x80000000, 0x00000000},
+        []su_int{0x078644FA, 0xFFFFFFFD, 0x00000000},
+        []su_int{0x078644FA, 0xFFFFFFFE, 0x00000000},
+        []su_int{0x078644FA, 0xFFFFFFFF, 0x00000000},
+        []su_int{0x0747AE14, 0x00000001, 0x0747AE14},
+        []su_int{0x0747AE14, 0x00000002, 0x03A3D70A},
+        []su_int{0x0747AE14, 0x00000003, 0x026D3A06},
+        []su_int{0x0747AE14, 0x00000010, 0x00747AE1},
+        []su_int{0x0747AE14, 0x078644FA, 0x00000000},
+        []su_int{0x0747AE14, 0x0747AE14, 0x00000001},
+        []su_int{0x0747AE14, 0x7FFFFFFF, 0x00000000},
+        []su_int{0x0747AE14, 0x80000000, 0x00000000},
+        []su_int{0x0747AE14, 0xFFFFFFFD, 0x00000000},
+        []su_int{0x0747AE14, 0xFFFFFFFE, 0x00000000},
+        []su_int{0x0747AE14, 0xFFFFFFFF, 0x00000000},
+        []su_int{0x7FFFFFFF, 0x00000001, 0x7FFFFFFF},
+        []su_int{0x7FFFFFFF, 0x00000002, 0x3FFFFFFF},
+        []su_int{0x7FFFFFFF, 0x00000003, 0x2AAAAAAA},
+        []su_int{0x7FFFFFFF, 0x00000010, 0x07FFFFFF},
+        []su_int{0x7FFFFFFF, 0x078644FA, 0x00000011},
+        []su_int{0x7FFFFFFF, 0x0747AE14, 0x00000011},
+        []su_int{0x7FFFFFFF, 0x7FFFFFFF, 0x00000001},
+        []su_int{0x7FFFFFFF, 0x80000000, 0x00000000},
+        []su_int{0x7FFFFFFF, 0xFFFFFFFD, 0x00000000},
+        []su_int{0x7FFFFFFF, 0xFFFFFFFE, 0x00000000},
+        []su_int{0x7FFFFFFF, 0xFFFFFFFF, 0x00000000},
+        []su_int{0x80000000, 0x00000001, 0x80000000},
+        []su_int{0x80000000, 0x00000002, 0x40000000},
+        []su_int{0x80000000, 0x00000003, 0x2AAAAAAA},
+        []su_int{0x80000000, 0x00000010, 0x08000000},
+        []su_int{0x80000000, 0x078644FA, 0x00000011},
+        []su_int{0x80000000, 0x0747AE14, 0x00000011},
+        []su_int{0x80000000, 0x7FFFFFFF, 0x00000001},
+        []su_int{0x80000000, 0x80000000, 0x00000001},
+        []su_int{0x80000000, 0xFFFFFFFD, 0x00000000},
+        []su_int{0x80000000, 0xFFFFFFFE, 0x00000000},
+        []su_int{0x80000000, 0xFFFFFFFF, 0x00000000},
+        []su_int{0xFFFFFFFD, 0x00000001, 0xFFFFFFFD},
+        []su_int{0xFFFFFFFD, 0x00000002, 0x7FFFFFFE},
+        []su_int{0xFFFFFFFD, 0x00000003, 0x55555554},
+        []su_int{0xFFFFFFFD, 0x00000010, 0x0FFFFFFF},
+        []su_int{0xFFFFFFFD, 0x078644FA, 0x00000022},
+        []su_int{0xFFFFFFFD, 0x0747AE14, 0x00000023},
+        []su_int{0xFFFFFFFD, 0x7FFFFFFF, 0x00000001},
+        []su_int{0xFFFFFFFD, 0x80000000, 0x00000001},
+        []su_int{0xFFFFFFFD, 0xFFFFFFFD, 0x00000001},
+        []su_int{0xFFFFFFFD, 0xFFFFFFFE, 0x00000000},
+        []su_int{0xFFFFFFFD, 0xFFFFFFFF, 0x00000000},
+        []su_int{0xFFFFFFFE, 0x00000001, 0xFFFFFFFE},
+        []su_int{0xFFFFFFFE, 0x00000002, 0x7FFFFFFF},
+        []su_int{0xFFFFFFFE, 0x00000003, 0x55555554},
+        []su_int{0xFFFFFFFE, 0x00000010, 0x0FFFFFFF},
+        []su_int{0xFFFFFFFE, 0x078644FA, 0x00000022},
+        []su_int{0xFFFFFFFE, 0x0747AE14, 0x00000023},
+        []su_int{0xFFFFFFFE, 0x7FFFFFFF, 0x00000002},
+        []su_int{0xFFFFFFFE, 0x80000000, 0x00000001},
+        []su_int{0xFFFFFFFE, 0xFFFFFFFD, 0x00000001},
+        []su_int{0xFFFFFFFE, 0xFFFFFFFE, 0x00000001},
+        []su_int{0xFFFFFFFE, 0xFFFFFFFF, 0x00000000},
+        []su_int{0xFFFFFFFF, 0x00000001, 0xFFFFFFFF},
+        []su_int{0xFFFFFFFF, 0x00000002, 0x7FFFFFFF},
+        []su_int{0xFFFFFFFF, 0x00000003, 0x55555555},
+        []su_int{0xFFFFFFFF, 0x00000010, 0x0FFFFFFF},
+        []su_int{0xFFFFFFFF, 0x078644FA, 0x00000022},
+        []su_int{0xFFFFFFFF, 0x0747AE14, 0x00000023},
+        []su_int{0xFFFFFFFF, 0x7FFFFFFF, 0x00000002},
+        []su_int{0xFFFFFFFF, 0x80000000, 0x00000001},
+        []su_int{0xFFFFFFFF, 0xFFFFFFFD, 0x00000001},
+        []su_int{0xFFFFFFFF, 0xFFFFFFFE, 0x00000001},
+        []su_int{0xFFFFFFFF, 0xFFFFFFFF, 0x00000001},
+    };
+
+    for (cases) |case| {
+        test_one_udivsi3(case[0], case[1], case[2]);
+    }
+}
+
+fn test_one_udivsi3(a: su_int, b: su_int, expected_q: su_int) {
+    const q: su_int = __udivsi3(a, b);
+    assert(q == expected_q);
+}
+
+
+fn assert(ok: bool) {
+    if (!ok) unreachable;
+}