Apple-2-SW/apple2_russian_peasant_multiplication
1
0
Fork 0
mirror of https://github.com/Michaelangel007/apple2_russian_peasant_multiplication.git synced 2025-01-02 15:29:22 +00:00
Code Issues Projects Releases Wiki Activity

Object Orientated Programming Javascript

Browse Source
This commit is contained in:
Michael Pohoreski 2016-08-17 14:23:09 -07:00
parent 5af3b5b4e5
commit 2dbc120e02
1 changed files with 273 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

273
rpm_oop.js Normal file
View File

@ -0,0 +1,273 @@
/* Object Orientated Version */
"use strict"; // Idiotic JavaScript design requires kludge for type safety
/*
To run from the command line:
node rpm_oop [-v] [# [#]]
Legend:
[] Paramater is optional
-v Turn on verbose output
# Number
Requires: node.js
*/
var LOG = 0; // Verbose logging
var BASE = 10;
var defaultA = "86";
var defaultB = "57";
// --------------------------------------------------------------------------------
// BCD Type
var BCD = function( width, text )
{
this.array = new Array( width );
if (text !== undefined)
this.Fill( text );
}
BCD.prototype =
{
constructor: BCD,
/** lhs += rhs
*/
// ========================================================================
Add2: function( rhs )
{
var n = this.array.length;
var carry = 0;
var sum = 0;
for( var i = 0; i < n; ++i )
{
sum = this.array[i] + rhs.array[i] + carry;
carry = (sum >= BASE) | 0;
if (sum >= BASE)
sum -= BASE;
this.array[ i ] = sum;
}
},
/** Print array BCD digits
* Stored little endian: LSB[0] MSB[n]
*/
// ========================================================================
Dump: function( prefix )
{
var n = this.array.length;
var text = prefix ? prefix : "";
for( var i = n - 1; i >= 0; --i )
text += this.array[ i ];
console.log( text );
},
/** Convert string to BCD array, aka, atoi()
Remaining digits are zero filled
* @param {Number[]} array
* @param {String} text
*/
// ========================================================================
Fill: function( text )
{
var i;
var n = this.array.length;
var m = text.length;
var v;
// Extra error checking would verify m > n
// Set all digits from string -- set in reverse order
for( i = 0; i < m; ++i )
this.array[ (m-1) - i ] = text.charCodeAt( i ) - 48;
// Set remaining digits to zero
for( ; i < n; ++i )
this.array[ i ] = 0;
},
// ========================================================================
isOdd: function()
{
return this.array[0] & 1 ? true : false;
},
// ========================================================================
isZero: function( )
{
var i;
var n = this.array.length;
var zero = true; // default to all zeroes until we find otherwise
for( i = 0; i < n; ++i )
zero &= (this.array[i] == 0);
return zero;
},
// Print array digits in reverse
// ========================================================================
Print: function( prefix )
{
var i;
var n = this.array.length;
var text = prefix ? prefix : "";
var zero = true; // assume leading zero -> skip digit
for( i = n - 1; i >= 0; --i )
{
zero &= (this.array[ i ] == 0);
if( !zero )
text += this.array[ i ];
}
console.log( text );
},
// ========================================================================
Shl1: function()
{
var i;
var n = this.array.length;
var carry = 0;
var sum = 0;
for( i = 0; i < n; ++i )
{
sum = this.array[ i ]*2 + carry;
carry = (sum >= BASE) | 0;
if (sum >= BASE)
sum -= BASE;
this.array[ i ] = sum;
}
},
// ========================================================================
Shr1: function()
{
var i;
var n = this.array.length;
var carry = 0;
var q = 0;
var div = 0;
var rem = 0;
for( i = n-1; i >= 0; --i )
{
div = this.array[ i ] + carry; // dividend
q = (div / 2) | 0; // 2 is divisor
this.array[i] = q;
rem = div - q*2; // 2 is divisor
carry = rem * BASE;
}
}
};
// --------------------------------------------------------------------------------
/** Russian Peasant Multiplication with native integers
* @param {Number} a
* @param {Number} b
*/
// ========================================================================
function RPM( x, y )
{
var a = x; // Javascript has no native unsigned 32-bit nor 64-bit integers
var b = y; // ctypes.UInt64() is only Firefox "extension"
var sum = 0;
while( b )
{
if (b & 1)
sum += a;
if(LOG) console.log( "A: " + a + ", B: " + b + ", Sum: " + sum );
if (a < 0)
return console.log( "ERROR: 31-bit integer overflow. Number too large after shifting left: " + x );
a <<= 1;
b >>= 1;
}
console.log( x + " x " + y + " = " + sum );
}
/** Russian Peasant Multiplication with strings
* @param {String} a
* @param {String} b
*/
// ========================================================================
function RPM_String( a, b )
{
var n = a.length; // i.e. 32-bit, e.g. 999
var m = b.length; // i.e. 32-bit e.g. 999
var s = n + m ; // i.e 32-bit * 32b-bit = 64-bit e.g. 998001
var digitsA = new BCD( s, a );
var digitsB = new BCD( s, b );
var digitsS = new BCD( s, "0" );
while( true )
{
var done = digitsB.isZero();
if( done )
break;
var odd = digitsB.isOdd();
if( odd )
digitsS.Add2( digitsA ); // S += A
if(LOG) digitsA.Dump( " A = " );
digitsA.Shl1();
if(LOG) digitsA.Dump( " A << " );
if(LOG) digitsB.Dump( " B = " );
digitsB.Shr1();
if(LOG) digitsB.Dump( " B >> " );
if(LOG) digitsS.Dump( "Sum: " );
}
digitsS.Print();
}
// ========================================================================
function main()
{
var args = process.argv.slice( process.execArgv.length + 2 );
var param = 0;
if (args[0] === '-v')
{
LOG = 1;
param++; // skip switches to first paramater
}
var params = [];
params.push( (args[param+0] === undefined) ? defaultA : args[param+0] );
params.push( (args[param+1] === undefined) ? defaultB : args[param+1] );
console.log( "= Integer = " );
RPM( params[0] | 0, params[1] | 0);
console.log( "\n" );
console.log( "= BCD String =" );
RPM_String( params[0], params[1] );
console.log( "\n" );
}
main();