TweetFollow Us on Twitter

Sep 96 Challenge
Volume Number:12
Issue Number:9
Column Tag:Programmer’s Challenge

Programmer’s Challenge

By Bob Boonstra

Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.

Byte Code Interpreter

September is Assembly Language month at the Programmer’s Challenge, and this year we will be accepting solutions in PowerPC Assembly for the first time. This month’s Challenge, suggested by Xan Gregg, is to write an interpreter for a subset of the byte code language used by the Java Virtual Machine.

The prototype for the code you should write is:

void JavaMiniVM(
 void *constant_pool,/* pointer to cp_info array */
 void *fields,   /* pointer to field_info array */
 void *methods,  /* pointer to method_info array */
 void *classFile,/* pointer to class file */
 long methodToExecute,  /* index of method to start executing */
 void *heapSpace,/* preallocated storage for your use */
 void *returnStack /* stack where return values are stored */
);

Your Challenge is to write an efficient interpreter for a subset of the Java byte code instruction set. A Java instruction consists of a single-byte opcode specifying the operation to be performed, followed by zero or more operand bytes. So, for example, in the byte sequence 0x10 0xFF, the opcode 0x10 (bipush) indicates that the operand byte 0xFF is to be pushed onto the operand stack. The instruction 0x60 (iadd) indicates that two integers are to be popped off the operand stack, added, and the result pushed back onto the stack. The virtual machine operates by repeatedly fetching an opcode and performing the indicated action on the operands.

To participate in this Challenge, you don’t need to know anything about Java itself, but you do need to understand the Java Virtual Machine. A Java Virtual Machine executes a .class file, the format of which is too complicated to provide here; it is described in the Java Virtual Machine Specification (release 1.0 Beta) available at http://java.sun.com/java.sun.com/newdocs.html.

The first three parameters passed to your JavaMiniVM routine are pointers to the constants, fields, and methods contained in the .class file that your interpreter is to execute. These parameters are taken directly from the classFile described in Section 2 of the VM specification. A pointer to the classFile is provided as the fourth parameter for those who feel they need direct access to the .class file. The parameter methodToExecute indicates which of the methods your VM is to start executing.

Stack space and execution frames should be established by your virtual machine in the memory provided in heapSpace. Adequate heap space will be allocated by the caller. Your code may include static data that might be needed for lookup tables, etc., to efficiently implement the virtual machine. The parameter returnStack is provided as the stack for the execution environment of the calling routine. It is to be used when executing the various return byte codes to provide the caller access to your results.

To simplify the Challenge, your code need not implement the long, float, and double data types supported by the Java Virtual Machine. You also do not need to process exceptions, breakpoints, monitored code regions, or the wide modifier for Load and Store instructions. Your interpreter should be robust enough to determine the operand size of these unimplemented instructions in order to skip any that are encountered. All methods invoked will be in the single .class file provided to your routine.

Sample test .class files will be provided via the Programmer’s Challenge mailing list, and are also available by writing me at bob_boonstra@mactech.com. If there are any questions about what needs to be implemented, please send me a note at the same email address.

Your code may be written in PowerPC Assembly, 68K Assembly, C, or C++. Testing will be performed on an 8500 using the latest CodeWarrior environment. Because this is a more difficult Challenge than usual, it has been sent to the mailing list earlier than normal to provide additional solution time. For those of you who haven’t had a chance to investigate Java in detail, it is a good opportunity to find out what all the excitement (hype?) is about. I hope you find this Challenge enjoyable and educational.

Two Months Ago Winner

Once again, congratulations go to Ernst Munter (Kanata, Ontario), this time for submitting the fastest entry to the Connect IV Challenge. Recall that the Challenge was to compete in a round-robin tournament against the other solutions in a generalized version of the well-known Connect 4 game. Pieces are inserted into the top of a column in the vertically oriented board, with the winner being the first player to arrange four or more pieces into a vertical, horizontal, or diagonal line.

Of the five entries I received, four worked completely or nearly correctly, although two of these occasionally forfeited a game by making an illegal move or incorrectly claiming victory. The two solutions winning the most tournament points required more execution time than the others, with the winning solution requiring the greatest amount of time for all but the largest board sizes. The winning solution uses a data structure dubbed a quad to denote each possible line of four pieces passing through a given point on the board, and keeps track of whether each quad represents a possible win for either player. Comments in the solution describe heuristics used to prune the recursive search for the best move.

Four test cases were used, consisting of different board sizes. Each solution competed twice against each other solution, playing once with the first move and once with the second move. The table below indicates how many points were earned by each entry for each of the board sizes:

Name7x716x1333x4863x62Total
Points
Greg Cooper666826
Louis Deaett042410
Ernst Munter1210121246
Keith Pomakis644014

The table below summarizes the results for each entry, including tournament points, code size, data size, and execution time. Numbers in parentheses after a person’s name indicate that person’s cumulative point total for all previous Challenges, not including this one.

Namepointstimesize
Ernst Munter (194)4662122944
Greg Cooper (7)2672721600
Keith Pomakis141113512
Louis Deaett10<14600

Top Twenty Contestants

Here are the top twenty contestants for the Programmer’s Challenge. The numbers below include points awarded over the twenty-four most recent contests, including points earned by this month’s entrants.

RankNamePointsRankNamePoints
1.Munter, Ernst20311.Cutts, Kevin21
2.Gregg, Xan9212.Picao, Miguel Cruz21
3.Larsson, Gustav8713.Brown, Jorg20
4.[Name deleted]6714.Gundrum, Eric20
5.Lengyel, Eric4015.Karsh, Bill19
6.Lewis, Peter3016.Stenger, Allen19
7.Darrah, Dave2917.Cooper, Greg17
8.Beith, Gary2418.Mallett, Jeff17
9.Kasparian, Raffi2219.Nevard, John17
10.Vineyard, Jeremy2220.Nicolle, Ludovic14

There are three ways to earn points: (1) scoring in the top five of any Challenge; (2) being the first person to find a bug in a published winning solution; or (3) being the first person to suggest a Challenge that I use. The points you can win are:

1st place 20 points 5th place 2 points

2nd place 10 points finding bug 2 points

3rd place 7 points suggesting Challenge 2 points

4th place 4 points

Here is Ernst’s winning solution:

ConnectMove.cp

Copyright © 1996 Ernst Munter

/*
    “Connect IV”

    The challenge is to write code for a well-known game that will compete against 
    other entries, as well as against the clock.  The game board consists of an NxM 
    array into which two players alternate inserting pieces. Pieces are inserted into the 
    top of a column in the vertically oriented board, so that they drop into the lowest 
    unoccupied cell of that column. The objective is to be the first player to arrange 4 
    or more pieces into a vertical, horizontal, or diagonal line.

Solution
--------
    My solution is based on an unsophisticated look-ahead scheme.  We search, depth 
    first, up to a maximum depth, to find the move which will give the highest board 
    score. Dummy moves are executed alternatingly by the 2 players, in a recursive 
    function.

    At each recursion level, the board score accumulated at the deeper levels is 
    subtracted from the value of the move contemplated at this level.

    In a full look-ahead to depth N, and with a board width of
    C columns, we would have C^N moves to examine.

    Two techniques are combined to reduce the number of moves to be examined:

    At each level, the search can stop if a certain threshold is exceeded or a winning 
    (losing) position is reached. Exceeding the threshold would mean that the calling 
    level could not gain a better score, given its best score to this point.

    In order to be able to stop searching (prune the tree), we would like to start with 
    moves which give the better scores, i.e. rather than go from left to right across
    the board, we start at the position of the last move and go alternatingly left and 
    right of that point. This tackles the active area of the board first where it is more 
    likely to find the best move.

Data Representation
-------------------
    The scoring relies entirely on a simple representation of the state of the board.

    The board is visualized as covered with potential lines (horizontal, vertical, 
    diagonal) of 4 adjacent fields.  Each such line is called a “quad”.

    A given field is associated with at least 3 (corner fields)
    and at most 16 such quads (in the center of a large board).

    Each quad can have a state (empty, owned by player 1, owned by player 2, or 
    spoiled). The spoiled state implies this quad contains pieces from both players, and 
    can no longer be a winning quad.

    In addition, a non-empty quad has a value, depending on how many player pieces it 
    contains.

    I have arbitrarily set these values as follows:

    empty 0
    1 piece                   1
    2 pieces   16
    3 pieces   256
    4 pieces   4096

    The value of a placing a piece in a given field, is calculated as the sum of the values 
    of all quads associated with this field.

    To simplify the book keeping, each field has an associated data structure which 
    points to all relevant quads.

    The Field structure also provides local stack space to hold the previous values of its 
    quads while a move is explored.

    A recognized weakness of this approach is that it treats all quads equally, and does 
    not recognize gravity, that is the need to fill columns from the bottom. This effect
    can shadow otherwise good candidates from ever winning. I had no time left to 
    include this consideration in the board scoring.

Running Time
------------
    The depth of the tree dramatically affects the time to compute a move, as does the 
    width of the board.

    A few minor techniques are used to improve running time.

    After each move, all spoiled quads are removed from their field references.

    All full columns are excluded from the move list.

    Empty columns “far away” from the action are also excluded.

    The MAGIC_NR constant can be used to adjust the speed of the program. A higher 
    value increases the search depth and the running time. 
    
    I set MAGIC_NR to 17 for acceptable all-round performance on my computer.

Assumptions
-----------
    At least 7 columns are assumed.
    The calling program should check for wins;
    it is assumed that this function is not called
    if the opponent has already won.

    A move value of -1 is returned when errors are detected, e.g when there are no free 
    fields left.

    This program does not include a randomizer since it is assumed it will play only a 
    few times against computer opponents who, we hope will not be able to take 
    advantage of this.

    In a version to be played by humans, one would randomly choose between equally 
    good moves to make it more interesting.

Note on style
-------------
    This program is basically a C program in spirit, but using C++ structs for 
    convenience in accessing dynamic data.

    No inheritance, operator overloading or the like.

    All simple functions are listed inline, as part of the class. The implementations of 
    functions with loops are listed separately, following the struct declaration.
*/

#include <stdlib.h>
#include "viervier.h"

#define maxRow 63
#define maxCol 64

#define maxQuad (((maxRow-3)*maxCol)+\
 ((maxCol-3)*maxRow)+(maxRow-3)*(maxCol-3)*2)
#define empty    0
#define self1
#define opponent 2
#define spoiled  3

#define OTHER_PLAYER (3-player)
#define WIN 4096
#define MAX_MOVES9

#define MAGIC_NR 17

Quad
struct Quad {
 short  status;  //who owns quad
 short  value;   //16 ^ (n-1);

 int  Update(int currentPlayer){
 if (status==empty) {
 status=(short)currentPlayer;
 value=1;
 return value;
 }
 if (status==currentPlayer) {
 value <<= 4;    //higher value
 return value;
 }
 if (status != spoiled) { //other player
 status=spoiled;
 return value;   //plus for us
 }
 return 0;//already spoiled
 }
};
typedef struct Quad Quad;

Field 
struct Field {
 Quad* quadRef[16];//pointers to intersecting quads
 Quad savedState[16];//stack to save quads before move

 void AddQuad(Quad* qp);
 void SaveState();
 void RestoreState();
 int  MakeMove(int currentPlayer);
 void Rationalize();
 int  IsEmpty(){
 if (quadRef[0]->status) return 0;
 return 1;
 }
};
typedef struct Field Field;

Field::AddQuad
void Field::AddQuad(Quad* qp) {    //adds qp to list of quads
int k;
 for (k=0;k<16;k++) {
 if (0==quadRef[k]) {
 quadRef[k]=qp;
 break;
 }
 }
}

Field::SaveState
void Field::SaveState() { //save all quads on stack
Quad* qp;
Quad**  qh=quadRef;
Quad* savePtr=savedState;
intk;
 for (k=0;k<16;k++) {
 if (0 == (qp=*qh++)) break;
 *savePtr++=*qp;
 }
}

Field::RestoreState
void Field::RestoreState() {//restore quads from stack
Quad* qp;
Quad**  qh=quadRef;
Quad* savePtr=savedState;
intk;
 for (k=0;k<16;k++) {
 if (0 == (qp=*qh++)) break;
 *qp=*savePtr++;
 }
}

Field::MakeMove
int Field::MakeMove(int currentPlayer) {
long  sum=0;
long  val;
Quad* qp;
Quad**  qh=quadRef;//move=update all quads
    //return value of move
intk;
 for (k=0;k<16;k++) {
 if (0 == (qp=*qh++)) break;
 val=qp->Update(currentPlayer);
 if (val>=WIN) {
 return WIN;
 }
 sum+=val;
 }
 return sum;
}

Field::Rationalize
void  Field::Rationalize() {
inti=0;
intk;
intnq=0;//remove all spoiled quads

//find number of non-0 quad refs
 for (k=0;k<16;k++) {
 if (quadRef[nq]) nq++;
 else break;
 }

//scan quad refs for spoiled quads, and remove
 while(i<nq) {
 Quad* qp=quadRef[i];
 if (qp->status==spoiled) {
 nq--;
 if (i<nq) quadRef[i]=quadRef[nq];
 quadRef[nq]=0;
 }
 i++;
 }
}

PrivateData 
struct PrivateData {
 int  nextMove;  //next real move to do
 int  numCols;   //number of columns
 int  numRows;   //number of rows
 int  numFree;   //number of fields free
 int  level;//recursion depth
 int  numMoves;  //number of moves in move list
 Field* endOfBoard;//sentinel pointer
 int  numHistory;//move counter
 int  history[maxCol*maxRow]; //move history
 int  moveList[maxCol];   //list of columns
 Field* nextField[maxCol];//next free field in column
 Field  board[maxCol*maxRow]; //array of all fields
 Quad quadSet[maxQuad];   //array of all quads

 void Initialize(long nCols,long nRows);
 void FirstMove() {nextMove = numCols >> 1;}
 void MakeMoveList(int move);
 int  BestMove(int level,int player,int threshold);
 void Rationalize(int move);
 int  CannedMove();
 void RecordMove(int move) {
 if (numHistory==0)
 history[numHistory++]=move;
 else history[numHistory++]=move-history[0];
 }
 void AdjustLevel() {
 level=MAGIC_NR - numMoves;
 if (numMoves<=7) level--;
 if (level>=numFree) level=numFree-1;
 }
 int  UpdateBoard(int move,int player) {
 Field* fp=nextField[move];
 long score=fp->MakeMove(player);
 nextField[move]=fp+numCols;
 Rationalize(move);
 numFree--;
 return score;
 }
};
typedef struct PrivateData PrivateData;

/*
field numbering example (6-by-7)

35             36 37  38         39 40  41               5           |
                        |
28             29 30  31         32 33  34               4           |
                        r
21             22 23  24         25 26  27               3           o
                        w
14             15 16  17         18 19  20               2           s
                        |
7        8           9           10  11         12 13  1    |
                        |
0        1           2           3           4           5           6           0           |
    -- columns --
*/

PrivateData::Initialize
void PrivateData::Initialize(long nCols,long nRows){
intcol,row;
Field*  field;
Quad*   qp;

 numCols=nCols;
 numRows=nRows;
 numFree = nCols*nRows;

 endOfBoard=board+numFree;

 field=board;
 for (col=0;col<nCols;col++)
 nextField[col]=field++;

 field=board;
 qp=quadSet;
 for (row=0;row<nRows;row++) {//set up quad references
 for (col=0;col<nCols;col++) {
 int direction,delta;
 for (direction=0;direction<4;direction++) {
 //right, up-right, up, up-left

 switch (direction) {
 //eliminate all that don’t fit
case 0: if (col>=nCols-3) continue;break;
case 1: if (col>=nCols-3) continue;
case 2: if (row>=nRows-3) continue;break;
case 3: if ((row>=nRows-3) || (col<3)) continue;
 }

 for (delta=0;delta<4;delta++) {
 Field* fp;
 switch (direction) {
case 0: fp=field+row*nCols+(col+delta);break;
case 1: fp=field+(row+delta)*nCols+(col+delta);break;
case 2: fp=field+(row+delta)*nCols+col;break;
case 3: fp=field+(row+delta)*numCols+(col-delta);break;
 }
 fp->AddQuad(qp);
 }
 qp++;
 }
 }
 }
}

PrivateData::Rationalize
void  PrivateData::Rationalize(int move) {

//remove spoiled quads from all free fields in the vicinity of a recent move

int i=move-3,j=move+4;
 if (i<0) i=0;
 if (j>numCols) j=numCols;
 for (;i<j;i++) {
 Field* fp=nextField[i];
 while (fp<endOfBoard) {
 fp->Rationalize();
 fp+=numCols;
 }
 }
}

PrivateData::MakeMoveList
void PrivateData::MakeMoveList(int move) {
intm=move;
intn=0;
intk=0;

//build the move sequence, starting from the center
//out to the limits while skipping full columns.

 do {
 if (nextField[m]<endOfBoard) moveList[n++]=m;
 if (n>=MAX_MOVES) goto done;
 k++;
 if (0>(m=m-k)) goto go_right;
 if (nextField[m]<endOfBoard) moveList[n++]=m;
 if (n>=MAX_MOVES) goto done;
 k++;
 if (numCols<=(m=m+k)) goto go_left;
 } while(1);

go_left:
 if (0>(m=m-k-1)) goto done;
 do {
 if (nextField[m]<endOfBoard) moveList[n++]=m;
 if (n>=MAX_MOVES) goto done;
 m--;
 } while(m>=0);
 goto done;

go_right:
 if (numCols<=(m=m+k+1)) goto done;
 do {
 if (nextField[m]<endOfBoard) moveList[n++]=m;
 if (n>=MAX_MOVES) goto done;
 m++;
 } while(m<numCols);

done:
 numMoves=n;
}

PrivateData::CannedMove
int PrivateData::CannedMove() {
#define H0 (history[0])
 switch (numHistory) {
case 1: if (H0>=3) return H0;
 if (H0+3<numCols) return H0;
 return numCols/2;
case 2: switch (history[1]) {
 case 0:return H0;
 case 1:if (H0>=3) return H0-3; else return H0;
 case -1:if (numCols-H0>3) return H0+3; else return H0;
 case 2:case -2:return H0;
 case 3:if (H0>=1) return H0-1; else return H0-1;
 case -3:if (numCols-H0>1) return H0+1; else return H0+1;
 default:if (H0>=2) return H0-1; else return H0+3;
 }
case 3: if (history[1]==0) {
 if (history[2]>=0) return H0-1;
 if (history[2]<0) {
 if (H0+1<numCols) return H0+1;
 }
 }
 }
 return -1;
}

PrivateData::BestMove
int PrivateData::BestMove(
 int level,int player,int threshold) {
inti;
intbestMove=-1;
intmoveValue;
intscore;
intbestV=-0x4000L;

//this routine is called recursively to return the value of the best move. The class //variable “nextMove” holds 
the column number for the “best” move.

 for (i=0;i<numMoves;i++) {
 int m=moveList[i];//work from list
 Field* fp=nextField[m];
 if (fp < endOfBoard) {   //else column is full
 fp->SaveState();
 nextField[m]+=numCols;
 moveValue = fp->MakeMove(player);

 if (moveValue>=WIN) {    //win here: return right away
 nextField[m]=fp;
 fp->RestoreState();
 nextMove=m;
 return WIN*2;
 }

 if (level) {    //descend to next level

 score=BestMove(level-1,OTHER_PLAYER,moveValue-bestV);
 if (score>=WIN) {
 moveValue=-score+1024;   //bias for depth
 goto skip;
 }
 moveValue -= score; //and accumulate score
 }

 if (moveValue>=threshold) {
 //no need to search further
 nextField[m]=fp;
 fp->RestoreState();
 nextMove=m;
 return moveValue;
 }
skip:
 if (moveValue>bestV) {   //keep track of best so far
 bestV=moveValue;
 bestMove=m;
 }

 nextField[m]=fp;
 fp->RestoreState();
 }
 }
 nextMove=bestMove;
 return bestV;
}

ConnectMove
long ConnectMove (
 long numCols,
 long numRows,
 void *privStorage,
 long prevMove,
 Boolean newGame,
 Boolean *victory) {

PrivateData* PD=(PrivateData*)privStorage;

 if (newGame) {  //initialize on first call
 PD->Initialize(numCols,numRows);
 if (prevMove==-1) {
 PD->FirstMove();//standard first move
 goto finish;
 }
 }


 PD->UpdateBoard(prevMove,2);
 PD->RecordMove(prevMove);

 if (PD->numFree<=0) return -1;    //the board is full

 if ((PD->nextMove=PD->CannedMove())<0) {

 PD->MakeMoveList(prevMove);

 PD->AdjustLevel();

 PD->BestMove(PD->level,1,WIN);
 }
finish:
 *victory=(WIN<=PD->UpdateBoard(PD->nextMove,1));
 PD->RecordMove(PD->nextMove);
 return PD->nextMove;
}

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

iFFmpeg 6.2.5 - Convert multimedia files...
iFFmpeg is a comprehensive media tool to convert movie, audio and media files between formats. The FFmpeg command line instructions can be very hard to master/understand, so iFFmpeg does all the hard... Read more
DaisyDisk 4.4 - $9.99
DaisyDisk allows you to visualize your disk usage and free up disk space by quickly finding and deleting big unused files. The program scans your disk and displays its content as a sector diagram... Read more
BetterTouchTool 2.07 - Customize Multi-T...
BetterTouchTool adds many new, fully customizable gestures to the Magic Mouse, Multi-Touch MacBook trackpad, and Magic Trackpad. These gestures are customizable: Magic Mouse: Pinch in / out (zoom... Read more
BetterTouchTool 2.071 - Customize Multi-...
BetterTouchTool adds many new, fully customizable gestures to the Magic Mouse, Multi-Touch MacBook trackpad, and Magic Trackpad. These gestures are customizable: Magic Mouse: Pinch in / out (zoom... Read more
BetterTouchTool 2.07 - Customize Multi-T...
BetterTouchTool adds many new, fully customizable gestures to the Magic Mouse, Multi-Touch MacBook trackpad, and Magic Trackpad. These gestures are customizable: Magic Mouse: Pinch in / out (zoom... Read more
PDFpen 8.3.2 - $74.95
PDFpen allows users to easily edit PDF's. Add text, images and signatures. Fill out PDF forms. Merge or split PDF documents. Reorder and delete pages. Even correct text and edit graphics! Features... Read more
DiskCatalogMaker 6.5.20 - Catalog your d...
DiskCatalogMaker is a simple disk management tool which catalogs disks. Simple, light-weight, and fast Finder-like intuitive look and feel Super-fast search algorithm Can compress catalog data for... Read more
Things 2.8.9 - Elegant personal task man...
Things is a task management solution that helps to organize your tasks in an elegant and intuitive way. Things combines powerful features with simplicity through the use of tags and its intelligent... Read more
PDFpenPro 8.3.2 - $124.95
PDFpenPro allows users to edit PDF's easily. Add text, images and signatures. Fill out PDF forms. Merge or split PDF documents. Reorder and delete pages. Create fillable forms and tables of content... Read more
Things 2.8.9 - Elegant personal task man...
Things is a task management solution that helps to organize your tasks in an elegant and intuitive way. Things combines powerful features with simplicity through the use of tags and its intelligent... Read more

Latest Forum Discussions

See All

Pokémon GO Generation 2 evolution guide
At long last, Niantic Labs finally unleashed the Generation 2 Pokémon into the wild. Pokémon GO trainers are scrambling to grab up this new set of 80 Pokémon. There are some special new tricks required to catch all of these new beasties, though.... | Read more »
The best new games we played this week
It feels as though the New Year got off to a creaking start as far as mobile games go, but that's changed over the past few weeks. The last few days alone have seen the debut of a number of wonderful games, so we thought we'd take the time to... | Read more »
Recruit more scallywags and discover new...
Get ready to show off your sea legs all over again in Oceans & Empires’ new grand update, which aims to make the act of rising to the role of seven seas ruler even more fresh and appealing, thanks to a richness of new content on both iOS and... | Read more »
Mage the Ascension: Refuge (Games)
Mage the Ascension: Refuge 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: The groundbreaking roleplaying game Mage: The Ascension manifests in our turbulent present with Refuge, an... | Read more »
Vampire: Prelude (Games)
Vampire: Prelude 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: The classic roleplaying game Vampire: The Masquerade returns to digital games with a Prelude of things to come. Experience a... | Read more »
Digby Forever Guide: How to dig to the d...
Digby Forever is a sparkling homage to arcade classics, and while you may be tiring of the number of arcade games being thrown at you, this endless digger finds many ways to stand out from the rest of the pack. The game manages to be challenging... | Read more »
The best sales on the App Store this wee...
It's been quite the week in mobile games, but if the latest releases(there were some pretty darn good ones, in case you missed out) aren't really doing the trick, perhaps some of these discounted games will. Many of these premium games had their... | Read more »
Why the new Fire Emblem Heroes update sh...
It’s exciting to see Nintendo delving into the mobile sphere, regardless of whether it’s to give fans another platform to enjoy their fans or simply a sound business venture. Two of the company's announced mobile games have finally come to... | Read more »
New Fire Emblem Heroes update adds new h...
Fire Emblem Heroes received a sizeable update first thing this morning. The update features a batch of fresh content along with a few updates to the game's systems. [Read more] | Read more »
The Deep Paths (Games)
The Deep Paths 1.0 Device: iOS iPhone Category: Games Price: $3.99, Version: 1.0 (iTunes) Description: 25% off launch sale!!! The Deep Paths: Labyrinth Of Andokost is a first-person, dungeon crawling RPG, with traditional grid-based... | Read more »

Price Scanner via MacPrices.net

15-inch Touch Bar MacBook Pros on sale for up...
Amazon has 15″ Touch Bar MacBook Pros in stock today and on sale for up to $150 off MSRP including free shipping: - 15″ 2.7GHz Touch Bar MacBook Pro Space Gray: $2720.38 $79 off MSRP - 15″ 2.7GHz... Read more
Apple’s Education discount saves up to $300 o...
Purchase a new Mac or iPad using Apple’s Education Store and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free: -... Read more
13-inch 1.6GHz/256GB MacBook Air on sale for...
Newegg has the 13″ 1.6GHz/256GB MacBook Air (MMGG2LL/A) on sale for $1029.99 including free shipping. Their price is $170 off MSRP, and it’s the lowest price available for this model. Choose Newegg... Read more
Save up to $600 with Apple refurbished Mac Pr...
Apple has Certified Refurbished Mac Pros available for up to $600 off the cost of new models. An Apple one-year warranty is included with each Mac Pro, and shipping is free. The following... Read more
12-inch 1.1GHz Retina MacBooks on sale for $1...
B&H has 12″ 1.1GHz Retina MacBooks on sale for $150 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 12″ 1.1GHz Space Gray Retina MacBook: $1149 $150 off MSRP - 12″ 1.1GHz... Read more
InTouch Health Expands iOS And Windows Produc...
Specialty telehealth enterprise provider InTouch Health has announced an expanded range of FDA Class I listed medical devices and software solutions for ambulatory, non-acute and non-emergent... Read more
iMobie Airs World’s 1st iCloud Manager with M...
iMobie Inc., an Apple-related software company, announced their newly-updated iPhone manager AnyTrans with exclusive feature to sync and manage contents across multiple iCloud accounts. With it,... Read more
New Proactive Apple Support Professional Cert...
Watchman Monitoring has announced Proactive Support Professional Certification at MacTech Pro. Watchman Monitoring is a premier Proactive Support Software as a Service (SaaS) tool for IT... Read more
13-inch 2.7GHz Retina MacBook Pro on sale for...
B&H Photo has the 2015 13″ 2.7GHz/128GB Retina Apple MacBook Pro on sale for $100 off MSRP. Shipping is free, and B&H charges NY tax only: - 13″ 2.7GHz/128GB Retina MacBook Pro (MF839LL/A): $... Read more
Back in stock: Apple refurbished 13-inch Reti...
Apple has Certified Refurbished 2015 13″ Retina MacBook Pros available for up to $360 off original MSRP, starting at $1099. An Apple one-year warranty is included with each model, and shipping is... Read more

Jobs Board

*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Manager *Apple* Systems Administration - Pu...
Req ID 3315BR Position Title Manager, Apple Systems Administration Job Description The Manager of Apple Systems Administration oversees the administration and Read more
*Apple* Retail - Multiple Positions - Apple,...
SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* macOS Systems Integration Administra...
…most exceptional support available in the industry. SCI is seeking an Junior Apple macOS systems integration administrator that will be responsible for providing Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.