1 /* The contents of this file are subject to the Netscape Public 2 * License Version 1.1 (the "License"); you may not use this file 3 * except in compliance with the License. You may obtain a copy of 4 * the License at http://www.mozilla.org/NPL/ 5 * 6 * Software distributed under the License is distributed on an "AS 7 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or 8 * implied. See the License for the specific language governing 9 * rights and limitations under the License. 10 * 11 * The Original Code is Mozilla Communicator client code, released March 12 * 31, 1998. 13 * 14 * The Initial Developer of the Original Code is Netscape Communications 15 * Corporation. Portions created by Netscape are 16 * Copyright (C) 1998 Netscape Communications Corporation. All 17 * Rights Reserved. 18 * 19 * Contributor(s): 20 * 21 */ 22 /** 23 File Name: 11.7.3.js 24 ECMA Section: 11.7.3 The unsigned right shift operator ( >>> ) 25 Description: 26 11.7.3 The unsigned right shift operator ( >>> ) 27 Performs a zero-filling bitwise right shift operation on the left argument 28 by the amount specified by the right argument. 29 30 The production ShiftExpression : ShiftExpression >>> AdditiveExpression is 31 evaluated as follows: 32 33 1. Evaluate ShiftExpression. 34 2. Call GetValue(Result(1)). 35 3. Evaluate AdditiveExpression. 36 4. Call GetValue(Result(3)). 37 5. Call ToUint32(Result(2)). 38 6. Call ToUint32(Result(4)). 39 7. Mask out all but the least significant 5 bits of Result(6), that is, 40 compute Result(6) & 0x1F. 41 8. Perform zero-filling right shift of Result(5) by Result(7) bits. 42 Vacated bits are filled with zero. The result is an unsigned 32 bit 43 integer. 44 9. Return Result(8). 45 46 Author: christine (at) netscape.com 47 Date: 12 november 1997 48 */ 49 var SECTION = "11.7.3"; 50 var VERSION = "ECMA_1"; 51 startTest(); 52 var testcases = getTestCases(); 53 54 writeHeaderToLog( SECTION + " The unsigned right shift operator ( >>> )"); 55 test(); 56 57 function test() { 58 for ( tc=0; tc < testcases.length; tc++ ) { 59 testcases[tc].passed = writeTestCaseResult( 60 testcases[tc].expect, 61 testcases[tc].actual, 62 testcases[tc].description +" = "+ 63 testcases[tc].actual ); 64 65 testcases[tc].reason += ( testcases[tc].passed ) ? "" : "wrong value "; 66 } 67 stopTest(); 68 return ( testcases ); 69 } 70 function getTestCases() { 71 var array = new Array(); 72 var item = 0; 73 74 var addexp = 0; 75 var power = 0; 76 77 for ( power = 0; power <= 32; power++ ) { 78 shiftexp = Math.pow( 2, power ); 79 80 for ( addexp = 0; addexp <= 32; addexp++ ) { 81 array[item++] = new TestCase( SECTION, 82 shiftexp + " >>> " + addexp, 83 UnsignedRightShift( shiftexp, addexp ), 84 shiftexp >>> addexp ); 85 } 86 } 87 88 return ( array ); 89 } 90 91 function ToInteger( n ) { 92 n = Number( n ); 93 var sign = ( n < 0 ) ? -1 : 1; 94 95 if ( n != n ) { 96 return 0; 97 } 98 if ( Math.abs( n ) == 0 || Math.abs( n ) == Number.POSITIVE_INFINITY ) { 99 return n; 100 } 101 return ( sign * Math.floor(Math.abs(n)) ); 102 } 103 function ToInt32( n ) { 104 n = Number( n ); 105 var sign = ( n < 0 ) ? -1 : 1; 106 107 if ( Math.abs( n ) == 0 || Math.abs( n ) == Number.POSITIVE_INFINITY) { 108 return 0; 109 } 110 111 n = (sign * Math.floor( Math.abs(n) )) % Math.pow(2,32); 112 n = ( n >= Math.pow(2,31) ) ? n - Math.pow(2,32) : n; 113 114 return ( n ); 115 } 116 function ToUint32( n ) { 117 n = Number( n ); 118 var sign = ( n < 0 ) ? -1 : 1; 119 120 if ( Math.abs( n ) == 0 || Math.abs( n ) == Number.POSITIVE_INFINITY) { 121 return 0; 122 } 123 n = sign * Math.floor( Math.abs(n) ) 124 125 n = n % Math.pow(2,32); 126 127 if ( n < 0 ){ 128 n += Math.pow(2,32); 129 } 130 131 return ( n ); 132 } 133 function ToUint16( n ) { 134 var sign = ( n < 0 ) ? -1 : 1; 135 136 if ( Math.abs( n ) == 0 || Math.abs( n ) == Number.POSITIVE_INFINITY) { 137 return 0; 138 } 139 140 n = ( sign * Math.floor( Math.abs(n) ) ) % Math.pow(2,16); 141 142 if (n <0) { 143 n += Math.pow(2,16); 144 } 145 146 return ( n ); 147 } 148 function Mask( b, n ) { 149 b = ToUint32BitString( b ); 150 b = b.substring( b.length - n ); 151 b = ToUint32Decimal( b ); 152 return ( b ); 153 } 154 function ToUint32BitString( n ) { 155 var b = ""; 156 for ( p = 31; p >=0; p-- ) { 157 if ( n >= Math.pow(2,p) ) { 158 b += "1"; 159 n -= Math.pow(2,p); 160 } else { 161 b += "0"; 162 } 163 } 164 return b; 165 } 166 function ToInt32BitString( n ) { 167 var b = ""; 168 var sign = ( n < 0 ) ? -1 : 1; 169 170 b += ( sign == 1 ) ? "0" : "1"; 171 172 for ( p = 30; p >=0; p-- ) { 173 if ( (sign == 1 ) ? sign * n >= Math.pow(2,p) : sign * n > Math.pow(2,p) ) { 174 b += ( sign == 1 ) ? "1" : "0"; 175 n -= sign * Math.pow( 2, p ); 176 } else { 177 b += ( sign == 1 ) ? "0" : "1"; 178 } 179 } 180 181 return b; 182 } 183 function ToInt32Decimal( bin ) { 184 var r = 0; 185 var sign; 186 187 if ( Number(bin.charAt(0)) == 0 ) { 188 sign = 1; 189 r = 0; 190 } else { 191 sign = -1; 192 r = -(Math.pow(2,31)); 193 } 194 195 for ( var j = 0; j < 31; j++ ) { 196 r += Math.pow( 2, j ) * Number(bin.charAt(31-j)); 197 } 198 199 return r; 200 } 201 function ToUint32Decimal( bin ) { 202 var r = 0; 203 204 205 for ( l = bin.length; l < 32; l++ ) { 206 bin = "0" + bin; 207 } 208 209 for ( j = 0; j < 32; j++ ) { 210 r += Math.pow( 2, j ) * Number(bin.charAt(31-j)); 211 212 } 213 214 return r; 215 } 216 function RShift( s, a ) { 217 s = ToUint32BitString( s ); 218 for ( z = 0; z < a; z++ ) { 219 s = "0" + s; 220 } 221 s = s.substring( 0, s.length - a ); 222 223 return ToUint32Decimal(s); 224 } 225 function UnsignedRightShift( s, a ) { 226 s = ToUint32( s ); 227 a = ToUint32( a ); 228 a = Mask( a, 5 ); 229 return ( RShift( s, a ) ); 230 } 231