/* The contents of this file are subject to the Netscape Public * License Version 1.1 (the "License"); you may not use this file * except in compliance with the License. You may obtain a copy of * the License at http://www.mozilla.org/NPL/ * * Software distributed under the License is distributed on an "AS * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or * implied. See the License for the specific language governing * rights and limitations under the License. * * The Original Code is Mozilla Communicator client code, released March * 31, 1998. * * The Initial Developer of the Original Code is Netscape Communications * Corporation. Portions created by Netscape are * Copyright (C) 1998 Netscape Communications Corporation. All * Rights Reserved. * * Contributor(s): * */ /** File Name: 11.7.1.js ECMA Section: 11.7.1 The Left Shift Operator ( << ) Description: Performs a bitwise left shift operation on the left argument by the amount specified by the right argument. The production ShiftExpression : ShiftExpression << AdditiveExpression is evaluated as follows: 1. Evaluate ShiftExpression. 2. Call GetValue(Result(1)). 3. Evaluate AdditiveExpression. 4. Call GetValue(Result(3)). 5. Call ToInt32(Result(2)). 6. Call ToUint32(Result(4)). 7. Mask out all but the least significant 5 bits of Result(6), that is, compute Result(6) & 0x1F. 8. Left shift Result(5) by Result(7) bits. The result is a signed 32 bit integer. 9. Return Result(8). Author: christine@netscape.com Date: 12 november 1997 */ var SECTION = "11.7.1"; var VERSION = "ECMA_1"; startTest(); var testcases = getTestCases(); writeHeaderToLog( SECTION + " The left shift operator ( << )"); test(); function test() { for ( tc=0; tc < testcases.length; tc++ ) { testcases[tc].passed = writeTestCaseResult( testcases[tc].expect, testcases[tc].actual, testcases[tc].description +" = "+ testcases[tc].actual ); testcases[tc].reason += ( testcases[tc].passed ) ? "" : "wrong value "; } stopTest(); return ( testcases ); } function getTestCases() { var array = new Array(); var item = 0; for ( power = 0; power < 33; power++ ) { shiftexp = Math.pow( 2, power ); for ( addexp = 0; addexp < 33; addexp++ ) { array[item++] = new TestCase( SECTION, shiftexp + " << " + addexp, LeftShift( shiftexp, addexp ), shiftexp << addexp ); } } return ( array ); } function ToInteger( n ) { n = Number( n ); var sign = ( n < 0 ) ? -1 : 1; if ( n != n ) { return 0; } if ( Math.abs( n ) == 0 || Math.abs( n ) == Number.POSITIVE_INFINITY ) { return n; } return ( sign * Math.floor(Math.abs(n)) ); } function ToInt32( n ) { n = Number( n ); var sign = ( n < 0 ) ? -1 : 1; if ( Math.abs( n ) == 0 || Math.abs( n ) == Number.POSITIVE_INFINITY) { return 0; } n = (sign * Math.floor( Math.abs(n) )) % Math.pow(2,32); n = ( n >= Math.pow(2,31) ) ? n - Math.pow(2,32) : n; return ( n ); } function ToUint32( n ) { n = Number( n ); var sign = ( n < 0 ) ? -1 : 1; if ( Math.abs( n ) == 0 || Math.abs( n ) == Number.POSITIVE_INFINITY) { return 0; } n = sign * Math.floor( Math.abs(n) ) n = n % Math.pow(2,32); if ( n < 0 ){ n += Math.pow(2,32); } return ( n ); } function ToUint16( n ) { var sign = ( n < 0 ) ? -1 : 1; if ( Math.abs( n ) == 0 || Math.abs( n ) == Number.POSITIVE_INFINITY) { return 0; } n = ( sign * Math.floor( Math.abs(n) ) ) % Math.pow(2,16); if (n <0) { n += Math.pow(2,16); } return ( n ); } function Mask( b, n ) { b = ToUint32BitString( b ); b = b.substring( b.length - n ); b = ToUint32Decimal( b ); return ( b ); } function ToUint32BitString( n ) { var b = ""; for ( p = 31; p >=0; p-- ) { if ( n >= Math.pow(2,p) ) { b += "1"; n -= Math.pow(2,p); } else { b += "0"; } } return b; } function ToInt32BitString( n ) { var b = ""; var sign = ( n < 0 ) ? -1 : 1; b += ( sign == 1 ) ? "0" : "1"; for ( p = 30; p >=0; p-- ) { if ( (sign == 1 ) ? sign * n >= Math.pow(2,p) : sign * n > Math.pow(2,p) ) { b += ( sign == 1 ) ? "1" : "0"; n -= sign * Math.pow( 2, p ); } else { b += ( sign == 1 ) ? "0" : "1"; } } return b; } function ToInt32Decimal( bin ) { var r = 0; var sign; if ( Number(bin.charAt(0)) == 0 ) { sign = 1; r = 0; } else { sign = -1; r = -(Math.pow(2,31)); } for ( var j = 0; j < 31; j++ ) { r += Math.pow( 2, j ) * Number(bin.charAt(31-j)); } return r; } function ToUint32Decimal( bin ) { var r = 0; for ( l = bin.length; l < 32; l++ ) { bin = "0" + bin; } for ( j = 0; j < 31; j++ ) { r += Math.pow( 2, j ) * Number(bin.charAt(31-j)); } return r; } function LeftShift( s, a ) { var shift = ToInt32( s ); var add = ToUint32( a ); add = Mask( add, 5 ); var exp = LShift( shift, add ); return ( exp ); } function LShift( s, a ) { s = ToInt32BitString( s ); for ( var z = 0; z < a; z++ ) { s += "0"; } s = s.substring( a, s.length); return ToInt32(ToInt32Decimal(s)); }