diff --git a/spec.html b/spec.html
index b272c6b8ab..f2825fdb2a 100644
--- a/spec.html
+++ b/spec.html
@@ -29232,8 +29232,7 @@ <h1>
               1. Set _k_ to _k_ + _cp_.[[CodeUnitCount]].
               1. Let _Octets_ be the List of octets resulting by applying the UTF-8 transformation to _cp_.[[CodePoint]].
               1. For each element _octet_ of _Octets_, do
-                1. Let _hex_ be the String representation of _octet_, formatted as an uppercase hexadecimal number.
-                1. Set _R_ to the string-concatenation of _R_, *"%"*, and StringPad(_hex_, 2, *"0"*, ~start~).
+                1. Set _R_ to the string-concatenation of _R_, *"%"*, and ZeroPad(_octet_, 2, ~hex-upper~).
           1. Return _R_.
         </emu-alg>
         <emu-note>
@@ -34026,9 +34025,9 @@ <h1>
           <dl class="header">
           </dl>
           <emu-alg>
-            1. Let _hour_ be ToZeroPaddedDecimalString(ℝ(HourFromTime(_tv_)), 2).
-            1. Let _minute_ be ToZeroPaddedDecimalString(ℝ(MinFromTime(_tv_)), 2).
-            1. Let _second_ be ToZeroPaddedDecimalString(ℝ(SecFromTime(_tv_)), 2).
+            1. Let _hour_ be ZeroPad(ℝ(HourFromTime(_tv_)), 2, ~decimal~).
+            1. Let _minute_ be ZeroPad(ℝ(MinFromTime(_tv_)), 2, ~decimal~).
+            1. Let _second_ be ZeroPad(ℝ(SecFromTime(_tv_)), 2, ~decimal~).
             1. Return the string-concatenation of _hour_, *":"*, _minute_, *":"*, _second_, the code unit 0x0020 (SPACE), and *"GMT"*.
           </emu-alg>
         </emu-clause>
@@ -34044,10 +34043,10 @@ <h1>
           <emu-alg>
             1. Let _weekday_ be the Name of the entry in <emu-xref href="#sec-todatestring-day-names"></emu-xref> with the Number WeekDay(_tv_).
             1. Let _month_ be the Name of the entry in <emu-xref href="#sec-todatestring-month-names"></emu-xref> with the Number MonthFromTime(_tv_).
-            1. Let _day_ be ToZeroPaddedDecimalString(ℝ(DateFromTime(_tv_)), 2).
+            1. Let _day_ be ZeroPad(ℝ(DateFromTime(_tv_)), 2, ~decimal~).
             1. Let _yv_ be YearFromTime(_tv_).
             1. If _yv_ is *+0*<sub>𝔽</sub> or _yv_ > *+0*<sub>𝔽</sub>, let _yearSign_ be the empty String; otherwise, let _yearSign_ be *"-"*.
-            1. Let _paddedYear_ be ToZeroPaddedDecimalString(abs(ℝ(_yv_)), 4).
+            1. Let _paddedYear_ be ZeroPad(abs(ℝ(_yv_)), 4, ~decimal~).
             1. Return the string-concatenation of _weekday_, the code unit 0x0020 (SPACE), _month_, the code unit 0x0020 (SPACE), _day_, the code unit 0x0020 (SPACE), _yearSign_, and _paddedYear_.
           </emu-alg>
           <emu-table id="sec-todatestring-day-names" caption="Names of days of the week">
@@ -34249,8 +34248,8 @@ <h1>
             1. Else,
               1. Let _offsetSign_ be *"-"*.
               1. Let _absOffset_ be -_offset_.
-            1. Let _offsetMin_ be ToZeroPaddedDecimalString(ℝ(MinFromTime(_absOffset_)), 2).
-            1. Let _offsetHour_ be ToZeroPaddedDecimalString(ℝ(HourFromTime(_absOffset_)), 2).
+            1. Let _offsetMin_ be ZeroPad(ℝ(MinFromTime(_absOffset_)), 2, ~decimal~).
+            1. Let _offsetHour_ be ZeroPad(ℝ(HourFromTime(_absOffset_)), 2, ~decimal~).
             1. Let _tzName_ be an implementation-defined string that is either the empty String or the string-concatenation of the code unit 0x0020 (SPACE), the code unit 0x0028 (LEFT PARENTHESIS), an implementation-defined timezone name, and the code unit 0x0029 (RIGHT PARENTHESIS).
             1. Return the string-concatenation of _offsetSign_, _offsetHour_, _offsetMin_, and _tzName_.
           </emu-alg>
@@ -34296,10 +34295,10 @@ <h1>Date.prototype.toUTCString ( )</h1>
           1. If _tv_ is *NaN*, return *"Invalid Date"*.
           1. Let _weekday_ be the Name of the entry in <emu-xref href="#sec-todatestring-day-names"></emu-xref> with the Number WeekDay(_tv_).
           1. Let _month_ be the Name of the entry in <emu-xref href="#sec-todatestring-month-names"></emu-xref> with the Number MonthFromTime(_tv_).
-          1. Let _day_ be ToZeroPaddedDecimalString(ℝ(DateFromTime(_tv_)), 2).
+          1. Let _day_ be ZeroPad(ℝ(DateFromTime(_tv_)), 2, ~decimal~).
           1. Let _yv_ be YearFromTime(_tv_).
           1. If _yv_ is *+0*<sub>𝔽</sub> or _yv_ > *+0*<sub>𝔽</sub>, let _yearSign_ be the empty String; otherwise, let _yearSign_ be *"-"*.
-          1. Let _paddedYear_ be ToZeroPaddedDecimalString(abs(ℝ(_yv_)), 4).
+          1. Let _paddedYear_ be ZeroPad(abs(ℝ(_yv_)), 4, ~decimal~).
           1. Return the string-concatenation of _weekday_, *","*, the code unit 0x0020 (SPACE), _day_, the code unit 0x0020 (SPACE), _month_, the code unit 0x0020 (SPACE), _yearSign_, _paddedYear_, the code unit 0x0020 (SPACE), and TimeString(_tv_).
         </emu-alg>
       </emu-clause>
@@ -34849,17 +34848,20 @@ <h1>
           </emu-note>
         </emu-clause>
 
-        <emu-clause id="sec-tozeropaddeddecimalstring" type="abstract operation">
+        <emu-clause id="sec-zeropad" type="abstract operation" oldids="sec-tozeropaddeddecimalstring">
           <h1>
-            ToZeroPaddedDecimalString (
+            ZeroPad (
               _n_: a non-negative integer,
               _minLength_: a non-negative integer,
+              _alphabet_: ~decimal~, ~hex-lower~, or ~hex-upper~,
             ): a String
           </h1>
           <dl class="header">
           </dl>
           <emu-alg>
-            1. Let _S_ be the String representation of _n_, formatted as a decimal number.
+            1. If _alphabet_ is ~hex-lower~, let _S_ be the String representation of _n_, formatted as a lowercase hexadecimal number.
+            1. Else if _alphabet_ is ~hex-upper~, let _S_ be the String representation of _n_, formatted as an uppercase hexadecimal number.
+            1. Else, let _S_ be the String representation of _n_, formatted as a decimal number.
             1. Return StringPad(_S_, _minLength_, *"0"*, ~start~).
           </emu-alg>
         </emu-clause>
@@ -45312,8 +45314,7 @@ <h1>
         <emu-alg>
           1. Let _n_ be the numeric value of _C_.
           1. Assert: _n_ ≤ 0xFFFF.
-          1. Let _hex_ be the String representation of _n_, formatted as a lowercase hexadecimal number.
-          1. Return the string-concatenation of the code unit 0x005C (REVERSE SOLIDUS), *"u"*, and StringPad(_hex_, 4, *"0"*, ~start~).
+          1. Return the string-concatenation of the code unit 0x005C (REVERSE SOLIDUS), *"u"*, and ZeroPad(_n_, 4, ~hex-lower~).
         </emu-alg>
       </emu-clause>
 
@@ -50108,11 +50109,9 @@ <h1>escape ( _string_ )</h1>
             1. Else,
               1. Let _n_ be the numeric value of _C_.
               1. If _n_ &lt; 256, then
-                1. Let _hex_ be the String representation of _n_, formatted as an uppercase hexadecimal number.
-                1. Let _S_ be the string-concatenation of *"%"* and StringPad(_hex_, 2, *"0"*, ~start~).
+                1. Let _S_ be the string-concatenation of *"%"* and ZeroPad(_n_, 2, ~hex-upper~).
               1. Else,
-                1. Let _hex_ be the String representation of _n_, formatted as an uppercase hexadecimal number.
-                1. Let _S_ be the string-concatenation of *"%u"* and StringPad(_hex_, 4, *"0"*, ~start~).
+                1. Let _S_ be the string-concatenation of *"%u"* and ZeroPad(_n_, 4, ~hex-upper~).
             1. Set _R_ to the string-concatenation of _R_ and _S_.
             1. Set _k_ to _k_ + 1.
           1. Return _R_.