diff --git a/std/assembly/string.ts b/std/assembly/string.ts
index 3624f63d3e..77585d9b77 100644
--- a/std/assembly/string.ts
+++ b/std/assembly/string.ts
@@ -30,16 +30,17 @@ import { Array } from "./array";
   }
 
   static fromCodePoint(code: i32): String {
-    assert(<u32>code <= 0x10FFFF);
-    var hasSur = code > 0xFFFF;
+    var hasSur = <u32>code > 0xFFFF;
     var out = changetype<String>(__new(2 << i32(hasSur), idof<String>()));
     if (!hasSur) {
       store<u16>(changetype<usize>(out), <u16>code);
     } else {
+      // Checks valid code point range
+      assert(<u32>code <= 0x10FFFF);
       code -= 0x10000;
       let hi = (code & 0x03FF) | 0xDC00;
-      let lo = (code >>> 10) | 0xD800;
-      store<u32>(changetype<usize>(out), lo | (hi << 16));
+      let lo = code >>> 10 | 0xD800;
+      store<u32>(changetype<usize>(out), lo | hi << 16);
     }
     return out;
   }
diff --git a/tests/compiler/std-wasi/process.optimized.wat b/tests/compiler/std-wasi/process.optimized.wat
index 97ea52e086..a2f6527925 100644
--- a/tests/compiler/std-wasi/process.optimized.wat
+++ b/tests/compiler/std-wasi/process.optimized.wat
@@ -4792,7 +4792,7 @@
   if
    i32.const 0
    i32.const 4816
-   i32.const 748
+   i32.const 749
    i32.const 7
    call $~lib/wasi/index/abort
    unreachable
diff --git a/tests/compiler/std-wasi/process.untouched.wat b/tests/compiler/std-wasi/process.untouched.wat
index 061e79a721..decdaf0529 100644
--- a/tests/compiler/std-wasi/process.untouched.wat
+++ b/tests/compiler/std-wasi/process.untouched.wat
@@ -7791,7 +7791,7 @@
   if
    i32.const 0
    i32.const 3792
-   i32.const 748
+   i32.const 749
    i32.const 7
    call $~lib/wasi/index/abort
    unreachable
diff --git a/tests/compiler/std/string-casemapping.optimized.wat b/tests/compiler/std/string-casemapping.optimized.wat
index 607b5b49c5..8aa51a1d63 100644
--- a/tests/compiler/std/string-casemapping.optimized.wat
+++ b/tests/compiler/std/string-casemapping.optimized.wat
@@ -5967,22 +5967,11 @@
   global.get $~lib/memory/__stack_pointer
   i32.const 0
   i32.store
-  local.get $0
-  i32.const 1114111
-  i32.gt_u
-  if
-   i32.const 0
-   i32.const 15344
-   i32.const 33
-   i32.const 5
-   call $~lib/builtins/abort
-   unreachable
-  end
   global.get $~lib/memory/__stack_pointer
   i32.const 2
   local.get $0
   i32.const 65535
-  i32.gt_s
+  i32.gt_u
   local.tee $2
   i32.shl
   i32.const 1
@@ -5991,6 +5980,17 @@
   i32.store
   local.get $2
   if
+   local.get $0
+   i32.const 1114111
+   i32.gt_u
+   if
+    i32.const 0
+    i32.const 15344
+    i32.const 39
+    i32.const 7
+    call $~lib/builtins/abort
+    unreachable
+   end
    local.get $1
    local.get $0
    i32.const 65536
diff --git a/tests/compiler/std/string-casemapping.untouched.wat b/tests/compiler/std/string-casemapping.untouched.wat
index 58d43bed23..cfb7e7640d 100644
--- a/tests/compiler/std/string-casemapping.untouched.wat
+++ b/tests/compiler/std/string-casemapping.untouched.wat
@@ -8589,20 +8589,8 @@
   i32.const 0
   i32.store
   local.get $0
-  i32.const 1114111
-  i32.le_u
-  i32.eqz
-  if
-   i32.const 0
-   i32.const 14576
-   i32.const 33
-   i32.const 5
-   call $~lib/builtins/abort
-   unreachable
-  end
-  local.get $0
   i32.const 65535
-  i32.gt_s
+  i32.gt_u
   local.set $1
   global.get $~lib/memory/__stack_pointer
   i32.const 2
@@ -8619,6 +8607,18 @@
    local.get $0
    i32.store16
   else
+   local.get $0
+   i32.const 1114111
+   i32.le_u
+   i32.eqz
+   if
+    i32.const 0
+    i32.const 14576
+    i32.const 39
+    i32.const 7
+    call $~lib/builtins/abort
+    unreachable
+   end
    local.get $0
    i32.const 65536
    i32.sub
diff --git a/tests/compiler/std/string-encoding.optimized.wat b/tests/compiler/std/string-encoding.optimized.wat
index bc55b7e596..7c76a4beb0 100644
--- a/tests/compiler/std/string-encoding.optimized.wat
+++ b/tests/compiler/std/string-encoding.optimized.wat
@@ -3883,7 +3883,7 @@
   if
    i32.const 0
    i32.const 1712
-   i32.const 748
+   i32.const 749
    i32.const 7
    call $~lib/builtins/abort
    unreachable
diff --git a/tests/compiler/std/string-encoding.untouched.wat b/tests/compiler/std/string-encoding.untouched.wat
index 947c9da3aa..65f2c9be39 100644
--- a/tests/compiler/std/string-encoding.untouched.wat
+++ b/tests/compiler/std/string-encoding.untouched.wat
@@ -5958,7 +5958,7 @@
   if
    i32.const 0
    i32.const 688
-   i32.const 748
+   i32.const 749
    i32.const 7
    call $~lib/builtins/abort
    unreachable
diff --git a/tests/compiler/std/string.optimized.wat b/tests/compiler/std/string.optimized.wat
index a4342fca7c..22257a02ee 100644
--- a/tests/compiler/std/string.optimized.wat
+++ b/tests/compiler/std/string.optimized.wat
@@ -2770,7 +2770,7 @@
   if
    i32.const 1264
    i32.const 1328
-   i32.const 56
+   i32.const 57
    i32.const 31
    call $~lib/builtins/abort
    unreachable
@@ -20364,22 +20364,11 @@
   global.get $~lib/memory/__stack_pointer
   i32.const 0
   i32.store
-  local.get $0
-  i32.const 1114111
-  i32.gt_u
-  if
-   i32.const 0
-   i32.const 1328
-   i32.const 33
-   i32.const 5
-   call $~lib/builtins/abort
-   unreachable
-  end
   global.get $~lib/memory/__stack_pointer
   i32.const 2
   local.get $0
   i32.const 65535
-  i32.gt_s
+  i32.gt_u
   local.tee $2
   i32.shl
   i32.const 1
@@ -20388,6 +20377,17 @@
   i32.store
   local.get $2
   if
+   local.get $0
+   i32.const 1114111
+   i32.gt_u
+   if
+    i32.const 0
+    i32.const 1328
+    i32.const 39
+    i32.const 7
+    call $~lib/builtins/abort
+    unreachable
+   end
    local.get $1
    local.get $0
    i32.const 65536
@@ -20988,7 +20988,7 @@
   if
    i32.const 13648
    i32.const 1328
-   i32.const 332
+   i32.const 333
    i32.const 7
    call $~lib/builtins/abort
    unreachable
diff --git a/tests/compiler/std/string.untouched.wat b/tests/compiler/std/string.untouched.wat
index 2b5ed767dd..5d8b16e859 100644
--- a/tests/compiler/std/string.untouched.wat
+++ b/tests/compiler/std/string.untouched.wat
@@ -3089,7 +3089,7 @@
   if
    i32.const 240
    i32.const 304
-   i32.const 56
+   i32.const 57
    i32.const 31
    call $~lib/builtins/abort
    unreachable
@@ -25393,20 +25393,8 @@
   i32.const 0
   i32.store
   local.get $0
-  i32.const 1114111
-  i32.le_u
-  i32.eqz
-  if
-   i32.const 0
-   i32.const 304
-   i32.const 33
-   i32.const 5
-   call $~lib/builtins/abort
-   unreachable
-  end
-  local.get $0
   i32.const 65535
-  i32.gt_s
+  i32.gt_u
   local.set $1
   global.get $~lib/memory/__stack_pointer
   i32.const 2
@@ -25423,6 +25411,18 @@
    local.get $0
    i32.store16
   else
+   local.get $0
+   i32.const 1114111
+   i32.le_u
+   i32.eqz
+   if
+    i32.const 0
+    i32.const 304
+    i32.const 39
+    i32.const 7
+    call $~lib/builtins/abort
+    unreachable
+   end
    local.get $0
    i32.const 65536
    i32.sub
@@ -26084,7 +26084,7 @@
   if
    i32.const 12624
    i32.const 304
-   i32.const 332
+   i32.const 333
    i32.const 7
    call $~lib/builtins/abort
    unreachable