Editorial: Express some Number methods more explicitly

Specifically, write
- Number::bitwiseNOT
- Number::leftShift
- Number::signedRightShift
- Number::unsignedRightShift

in terms of NumberToInt32Bits/Int32BitsToNumber
or the analogous NumberToUint32Bits/Uint32BitsToNumber.

spec.html

@@ -1880,8 +1880,9 @@ <h1>
           <dl class="header">
           </dl>
           <emu-alg>
-            1. Let _oldValue_ be ! ToInt32(_x_).
-            1. Return the bitwise complement of _oldValue_. The mathematical value of the result is exactly representable as a 32-bit two's complement bit string.
+            1. Let _xbits_ be NumberToInt32Bits(_x_).
+            1. Let _cbits_ be the bitwise complement of _xbits_.
+            1. Return Int32BitsToNumber(_cbits_).
           </emu-alg>
         </emu-clause>
 
@@ -2084,10 +2085,11 @@ <h1>
           <dl class="header">
           </dl>
           <emu-alg>
-            1. Let _lnum_ be ! ToInt32(_x_).
+            1. Let _lbits_ be NumberToInt32Bits(_x_).
             1. Let _rnum_ be ! ToUint32(_y_).
             1. Let _shiftCount_ be ℝ(_rnum_) modulo 32.
-            1. Return the result of left shifting _lnum_ by _shiftCount_ bits. The mathematical value of the result is exactly representable as a 32-bit two's complement bit string.
+            1. Let _shifted_ be the result of left shifting _lbits_ by _shiftCount_ bits.
+            1. Return Int32BitsToNumber(_shifted_).
           </emu-alg>
         </emu-clause>
 
@@ -2101,10 +2103,11 @@ <h1>
           <dl class="header">
           </dl>
           <emu-alg>
-            1. Let _lnum_ be ! ToInt32(_x_).
+            1. Let _lbits_ be NumberToInt32Bits(_x_).
             1. Let _rnum_ be ! ToUint32(_y_).
             1. Let _shiftCount_ be ℝ(_rnum_) modulo 32.
-            1. Return the result of performing a sign-extending right shift of _lnum_ by _shiftCount_ bits. The most significant bit is propagated. The mathematical value of the result is exactly representable as a 32-bit two's complement bit string.
+            1. Let _shifted_ be the result of performing a sign-extending right shift of _lbits_ by _shiftCount_ bits. The most significant bit is propagated.
+            1. Return Int32BitsToNumber(_shifted_).
           </emu-alg>
         </emu-clause>
 
@@ -2118,10 +2121,11 @@ <h1>
           <dl class="header">
           </dl>
           <emu-alg>
-            1. Let _lnum_ be ! ToUint32(_x_).
+            1. Let _lbits_ be NumberToUint32Bits(_x_).
             1. Let _rnum_ be ! ToUint32(_y_).
             1. Let _shiftCount_ be ℝ(_rnum_) modulo 32.
-            1. Return the result of performing a zero-filling right shift of _lnum_ by _shiftCount_ bits. Vacated bits are filled with zero. The mathematical value of the result is exactly representable as a 32-bit unsigned bit string.
+            1. Let _shifted_ be the result of performing a zero-filling right shift of _lbits_ by _shiftCount_ bits. Vacated bits are filled with zero.
+            1. Return Uint32BitsToNumber(_shifted_).
           </emu-alg>
         </emu-clause>
 
@@ -2256,6 +2260,34 @@ <h1>
           </emu-alg>
         </emu-clause>
 
+        <emu-clause id="sec-numbertouint32bits" type="abstract operation">
+          <h1>
+            NumberToUint32Bits (
+              _number_: a Number,
+            ): a 32-bit bit string
+          </h1>
+          <dl class="header">
+          </dl>
+          <emu-alg>
+            1. Let _n_ be ! ToUint32(_number_).
+            1. Return the 32-bit unsigned bit string representing ℝ(_n_).
+          </emu-alg>
+        </emu-clause>
+
+        <emu-clause id="sec-uint32bitstonumber" type="abstract operation">
+          <h1>
+            Uint32BitsToNumber (
+              _bits_: a 32-bit bit string,
+            ): an integral Number
+          </h1>
+          <dl class="header">
+          </dl>
+          <emu-alg>
+            1. Let _i_ be the result of interpreting _bits_ as a 32-bit unsigned integer.
+            1. Return 𝔽(_i_).
+          </emu-alg>
+        </emu-clause>
+
         <emu-clause id="sec-numeric-types-number-bitwiseAND" type="numeric method">
           <h1>
             Number::bitwiseAND (