Sep 95 Challenge
 Volume Number: 11 Issue Number: 9 Column Tag: Programmer’s Challenge

# Programmer’s Challenge

By Bob Boonstra, Westford, Massachusetts

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

## Reversible Scrambling Algorithm

According to tradition, September is Assembly Language Challenge month here at MacTech, and we continue that tradition this month. Your challenge is to do some simple arithmetic - raising a number to a power, and taking the remainder of the result modulo another number. Simple, right? To make things interesting, though, the numbers are going to be a little larger than you are used to dealing with. Hundreds of decimal digits long, in fact. “Why,” you may ask? We’ll get into that in a minute, but there are a couple of hints in the title of this month’s challenge.

The data structure to be used for the large numbers in this Challenge, and the prototype for the code you should write are:

```typedef struct BigNum {
short numDig;   /* the number of bytes in the BigNum */
unsigned char *dig; /* dig[0] is the most significant byte */
/* dig[numDig-1] is least significant */
} BigNum;

void PowerAndRemainder(
BigNum *msg,
BigNum *exp,    /* calculate msg to the exp power, */
BigNum *n, /* take the remainder modulo n */
BigNum *res/* and store the result in res */
);

```

For example, the value 1048573 (0xFFFFD) would be provided to you in a BigNum b with the values b.numDig=3, b.dig[0] = 0x0F, b.dig[1]=0xFF, and b.dig[2]=0xFD. The first three arguments will be provided as input when PowerAndRemainder is called; you are to generate both elements of the BigNum struct for the res argument. The storage for all of the BigNums in the call to PowerAndRemainder will be allocated by the caller. All BigNums will be positive integers, and none of the BigNums will be larger than 128 bytes in length (i.e., b.numDig will be no larger than 128). There is no restriction on the amount of memory you may use (within reason).

Those of you with some number theory in your background may recognize what a function like this might be used for. If the modulus n is the product of two large primes p and q, one can find values e and d for the exponent with the property that they are inverses of one another, but that neither can be easily derived from the other, provided prime numbers p and q are not divulged. If you calculate PowerAndRemainder(msg,e,n,c), and I then calculate PowerAndRemainder(c,d,n,x), then the result x turns out to be identical to the original value msg if e and d are relatively prime to (p-1)*(q-1). Now what do you suppose such a function might be useful for?

Your solution may use any combination of ANSI C and/or 68K assembly language, along with your choice of either the THINK C or MetroWerks C 68K compilers. I considered making this a PowerPC challenge, but I wasn’t confident that enough people are proficient with PPC assembly just yet - perhaps next September. In the meantime, you can look forward to a native PPC challenge next month.

If you are interested in some sample values to test your code, send me email and I’ll provide some.

Several people wrote to point out that the deadline for submitting Challenge solutions was missing from the Rules box during July and August. Unfortunately, when the rules were revised to accommodate multiple compilers and target instruction sets, the deadline was inadvertently omitted. The Challenge deadline remains the 10th of the month printed on the cover of the magazine. I received several submissions for the Chess challenge after the deadline (and after the article was submitted for publication). Because of the problem with the deadline, I would have awarded points to any fast and correct entries, but all of the late entries had problems with correctness so no additional points were awarded.

## Two Months Ago Winner

Of the nine entries to the Sprite Blitz challenge, seven of them worked correctly. Congratulations to Xan Gregg (Durham, NC) for having the fastest solution, some 30% faster than the second place entry, submitted by John Nevard. Despite the variation in run time performance, there were a number of clever and creative solutions among the top entries.

Here are the times and code sizes for the entries that worked correctly. Numbers in parens after a person’s name indicate that person’s cumulative point total for all previous Challenges, not including this one.

Name time (68K)

Xan Gregg (31) 908

John Nevard 1300

Bill Karsh (71) 3363

Jim Bumgardner (4) 3495

Jeremy Vineyard (40) 5789

Norman Basham 10164

Steve Israelson 75846

Like most of the top entries, Xan composed his screen updates offscreen. Xan uses one offscreen GWorld to hold the background and another to prepare the next animation frame. One clever trick is that the offscreen image is large enough to contain all of a sprite that overlaps a window boundary, so that clipping need only be done when updating the window. Drawing is done directly to the screen, taking advantage of alignment conditions guaranteed to hold by the problem statement. Xan does all of his copying to the screen using unrolled loops, avoiding the overhead incurred when using CopyBits or CopyMask for small copies. When reading the code, take note of the switch statement in the COPY4 macro that copies the icon based on the value of the mask, and of the longword copies in the FastCopyChunk routine.

Bill Karsh pointed out in his entry that the relative performance of CopyBits and CopyMask varies between his 68K machine and his PPC 7100, with CopyBits being faster on the former machine and CopyMask being faster on the latter. I didn’t have time to measure native performance on the PowerPC, but there was a 15% difference between the two versions in my 68K tests. Of course, as Xan’s solution shows, avoiding both can have its advantages also.

## Does Performance Matter?

I’ve received some email suggesting that the emphasis on performance in this column ought to be replaced by emphases on other things, like code portability, readability, reliability, encapsulation, or object orientation. The argument is that improvements in hardware performance make efficiency less important than it has been in the past. This is certainly a valid point of view, and there is no question that processor improvements have enabled us to sacrifice some machine cycles to achieve objectives other than performance. However, I contend that the performance of several popular personal computer applications demonstrates that software developers are capable of adding enough functionality (or generating poor enough code) to degrade performance to an unacceptable level, despite hardware advances. In my opinion, this will always be so. Certainly the techniques demonstrated in this column should not be used in all software, but they have their place in time-critical areas, and it is worth devoting more attention to efficiency than we typically do. Besides, squeezing instructions out of code is great fun! But if you are interested in seeing a column that focuses on something besides efficiency, drop me a note.

## Top 20 Contestants of All Time

Here are the Top 20 Contestants for the Programmer’s Challenges to date. The numbers below include points awarded for this month’s entrants. (Note: ties are listed alphabetically by last name - there are more than 20 people listed this month because of ties.)

1. [Name deleted] 176

2. Karsh, Bill 78

3. Munter, Ernst 70

4. Stenger, Allen 65

6. Gregg, Xan 51

7. Riha, Stepan 51

8. Goebel, James 49

9. Nepsund, Ronald 47

10. Cutts, Kevin 46

11. Mallett, Jeff 44

12. Kasparian, Raffi 42

13. Vineyard, Jeremy 42

14. Darrah, Dave 31

15. Landry, Larry 29

16. Elwertowski, Tom 24

17. Lee, Johnny 22

18. Noll, Robert 22

19. Anderson, Troy 20

20. Beith, Gary 20

21. Burgoyne, Nick 20

22. Galway, Will 20

23. Israelson, Steve 20

24. Landweber, Greg 20

25. Pinkerton, Tom 20

There are three ways to earn points: (1) scoring in the top 5 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

2nd place 10 points

3rd place 7 points

4th place 4 points

5th place 2 points

finding bug 2 points

suggesting Challenge 2 points

Here is Xan’s winning solution:

## Sprite Blitz

```Xan Gregg, July 1995
/*
Since “correctness” is considered before speed in judging solutions, this solution makes correctness the
top priority at the cost of speed.

I use two offscreen GWorlds.  One has the background, and another has the image to be displayed on the
screen next.  The “on deck” image is updated sprite by sprite, then it is copied to the screen for minimum
flicker.

The GWorlds are a little bigger than the screen so I don’t have to worry about sprites that overlap the edges
until copying to the screen.

Memory usage:
2 GWorlds, each 64 pixels wider and taller than window.
1K of pixel data for each sprite.
128 bytes of mask data for each sprite.
16 bytes of info for each sprite.
I set the number of sprites to 400.  The problem states a maximum of 200 present at a time, but because
a deleted sprite stays around until the next UpdateScreen() call,
I allow for 400 in case you delete all 200 then add 200 more before calling UpdateScreen().  Paranoid, but
if you’ve got the memory...

Assumptions not stated in the problem:
Enough memory available for above usage.
Window width is a multiple of 4 (confirmed by BB).
Window does not move during play.

*/

#include <QDOffscreen.h>

typedef struct
{
short  nextSlot;
short  status;
short  width;
short  height;
Point  position;
Point  lastPosition;
} SpriteInfo, *SpriteInfoPtr;

typedef struct
{
char pixData[1024];
} SpritePixData, *SpritePixDataPtr;

typedef struct
{

#define kMaxSprites400L
#define kMaxSpriteWidth   32L
#define kMaxSpriteHeight  32L

static CWindowPtrgScreenWindowP;
static GWorldPtr gBackgroundGW;
static PixMapHandlegBackgroundPixMapH;
static GWorldPtr gOnDeckGW;
static PixMapHandlegOnDeckPixMapH;
static shortgLastSpriteSlot;
static shortgFirstSpriteSlot;
static shortgSpriteCount;
static shortgWindowWidth;
static shortgWindowHeight;
static SpriteInfoPtr gSpriteInfo;
static SpritePixDataPtr gSpritePixData;
static long gOnDeckRowBytes;
static long gBkgRowBytes;
static long gScreenRowBytes;
static shortgDeletionCount;

StartGame
void StartGame(CWindowPtr windowP)
{
Rect   r;
PixMapPtrbkgPixMapP;
PixMapPtronDeckPixMapP;
PixMapPtrscreenPixMapP;

gLastSpriteSlot = -1;
gFirstSpriteSlot = -1;
gSpriteCount = 0;
gDeletionCount = 0;
gScreenWindowP = windowP;
r = windowP->portRect;
OffsetRect(&r, -r.left, -r.top);
gWindowWidth = r.right;
gWindowHeight = r.bottom;

InsetRect(&r, -kMaxSpriteWidth, -kMaxSpriteHeight);
NewGWorld(&gBackgroundGW, 0, &r, 0, 0, 0);
gBackgroundPixMapH = GetGWorldPixMap(gBackgroundGW);
LockPixels(gBackgroundPixMapH); /* always locked */
NewGWorld(&gOnDeckGW, 0, &r, 0, 0, 0);
gOnDeckPixMapH = GetGWorldPixMap(gOnDeckGW);
LockPixels(gOnDeckPixMapH);/* always locked */

gSpriteInfo = (SpriteInfoPtr) NewPtrClear
(sizeof(SpriteInfo) * kMaxSprites);
gSpritePixData = (SpritePixDataPtr) NewPtrClear
(sizeof(SpritePixData) * kMaxSprites);
gBkgRowAddr = (Ptr *) NewPtr(sizeof(Ptr) *
(gWindowHeight + kMaxSpriteHeight * 2));
gOnDeckRowAddr = (Ptr *) NewPtr(sizeof(Ptr) *
(gWindowHeight + kMaxSpriteHeight * 2));
* (long) gWindowHeight);
if (gSpriteInfo == 0 || gSpritePixData == 0
|| gBackgroundGW == 0 || gOnDeckGW == 0)
DebugStr("\p out of memory!");
InsetRect(&r, kMaxSpriteWidth, kMaxSpriteHeight);
OffsetRect(&r, kMaxSpriteWidth, kMaxSpriteHeight);
CopyBits(&((WindowPtr)windowP)->portBits,
&((WindowPtr)gBackgroundGW)->portBits,
&windowP->portRect, &r, srcCopy, NULL);
CopyBits(&((WindowPtr)windowP)->portBits,
&((WindowPtr)gOnDeckGW)->portBits,
&windowP->portRect, &r, srcCopy, NULL);

bkgPixMapP = *gBackgroundPixMapH;
onDeckPixMapP = *gOnDeckPixMapH;
gOnDeckRowBytes = onDeckPixMapP->rowBytes & 0x7fff;
+ gOnDeckRowBytes * kMaxSpriteHeight
+ kMaxSpriteWidth;
gBkgRowBytes = bkgPixMapP->rowBytes & 0x7fff;
+ gBkgRowBytes * kMaxSpriteHeight
+ kMaxSpriteWidth;
screenPixMapP = *gScreenWindowP->portPixMap;
gScreenRowBytes = screenPixMapP->rowBytes & 0x7fff;
- screenPixMapP->bounds.left
- screenPixMapP->bounds.top
* gScreenRowBytes;

long row;

for (row = -kMaxSpriteHeight;
row < gWindowHeight + kMaxSpriteHeight; row++)
{
+ row * gBkgRowBytes;
+ row * gOnDeckRowBytes;
}
for (row = 0; row < gWindowHeight; row++)
+ row * gScreenRowBytes;
}
}

/* make a copy of CIcon’s pixel and mask data */
{
short  slot;
short  i;
short  pixWidth;
short  pixBytes;
short  bitBytes;
short  height;

slot = gLastSpriteSlot + 1;
if (slot == kMaxSprites)
slot = 0;
while (gSpriteInfo[slot].status != 0)
{
slot++;
if (slot == kMaxSprites)
slot = 0;
}
gSpriteInfo[slot].status = 1;/* occupied */
height = cIconP->iconPMap.bounds.bottom
- cIconP->iconPMap.bounds.top;
pixWidth = cIconP->iconPMap.bounds.right
- cIconP->iconPMap.bounds.left;
maskWidth = (pixWidth + 7) >> 3;
gSpriteInfo[slot].width = pixWidth;
gSpriteInfo[slot].height = height;
pixBytes = cIconP->iconPMap.rowBytes & 0x7fff;
bitBytes = cIconP->iconBMap.rowBytes;
+ bitBytes * height
+ 256 * 8 + 8;  /* 8-bit color table */

pixWidth = pixWidth >> 2;
for (i = 0; i < height; i++)
{
{
register long *q = (long *) pixDstAddr;
register long *p = (long *) pixSrcAddr;
register short  j = pixWidth;
while (j > 0)
{
*q++ = *p++;
j--;
}
}
}

if (gLastSpriteSlot >= 0)
{
gSpriteInfo[gLastSpriteSlot].nextSlot = slot;
}
else
{
gFirstSpriteSlot = slot;
}
gLastSpriteSlot = slot;
gSpriteInfo[slot].nextSlot = -1;
gSpriteInfo[slot].position = startPt;
gSpriteInfo[slot].lastPosition = startPt;
gSpriteCount ++;
return slot;
}

EraseSprite
/* replace sprite with chunk from the bkg gworld */
static void EraseSprite(SpriteInfoPtr spriteInfoP)
{
short  numRows;
short  numCols;
register long *p;
register long *q;
short  h, v;
register long srcRowBytes;
register long dstRowBytes;

numRows = spriteInfoP->height;
numCols = spriteInfoP->width;
h = spriteInfoP->lastPosition.h;
v = spriteInfoP->lastPosition.v;
if (h + numCols <= 0 || h >= gWindowWidth
|| v + numRows <= 0 || v >= gWindowHeight)
return;/* totally offscreen, so skip it */

p = (long *) (gBkgRowAddr[v] + h);
q = (long *) (gOnDeckRowAddr[v] + h);
srcRowBytes = gBkgRowBytes - numCols;
dstRowBytes = gOnDeckRowBytes - numCols;
if (numCols >= 16)
if (numCols == 32)
{
while (numRows != 0)
{
numRows--;
*q++ = *p++;
*q++ = *p++;
*q++ = *p++;
*q++ = *p++;
*q++ = *p++;
*q++ = *p++;
*q++ = *p++;
*q++ = *p++;
p = (long *) (((Ptr) p) + srcRowBytes);
q = (long *) (((Ptr) q) + dstRowBytes);
}
}
else
{
while (numRows != 0)
{
numRows--;
*q++ = *p++;
*q++ = *p++;
*q++ = *p++;
*q++ = *p++;
p = (long *) (((Ptr) p) + srcRowBytes);
q = (long *) (((Ptr) q) + dstRowBytes);
}
}
else
{
if (numCols < 8)
while (numRows != 0)
{
numRows--;
*q = *p;
p = (long *) (((Ptr) p) + gBkgRowBytes);
q = (long *) (((Ptr) q) + gOnDeckRowBytes);
}
else /* erase 4 pixels, even if its smaller */
while (numRows != 0)
{
numRows--;
*q++ = *p++;
*q++ = *p++;
p = (long *) (((Ptr) p) + srcRowBytes);
q = (long *) (((Ptr) q) + dstRowBytes);
}
}
}

DeleteSprite

/* Don’t actually do the delete, just mark for deletion -- because we still
need to erase it in UpdateScreen()
*/
void DeleteSprite(short spriteID)
{
gSpriteInfo[spriteID].status = -1;/* to be deleted */
gDeletionCount++;
}

RemoveDeletedSprites
/* only called when there is at least one deletion */
static void RemoveDeletedSprites(void)
{
short  prevSlot = -1;
short  slot = gFirstSpriteSlot;
short  count = gDeletionCount;

while (1)
{
if (gSpriteInfo[slot].status < 0)
{/* needs to be removed */
if (prevSlot >= 0)
gSpriteInfo[prevSlot].nextSlot
= gSpriteInfo[slot].nextSlot;
else
gFirstSpriteSlot
= gSpriteInfo[slot].nextSlot;
if (slot == gLastSpriteSlot)
gLastSpriteSlot = prevSlot;
gSpriteInfo[slot].status = 0;/* available */
gSpriteCount--;
count--;
if (count == 0)
break;
}
else
{
prevSlot = slot;
}
slot = gSpriteInfo[slot].nextSlot;
}
gDeletionCount = 0;
}

MoveSprite
void MoveSprite(short spriteID, Point deltaPt)
{
gSpriteInfo[spriteID].position.h += deltaPt.h;
gSpriteInfo[spriteID].position.v += deltaPt.v;
}

EraseOldSprites
static void EraseOldSprites(void)
{
short  slot;
SpriteInfoPtr spriteInfoP;

slot = gFirstSpriteSlot;
while (slot >= 0)
{
spriteInfoP = &gSpriteInfo[slot];
EraseSprite(spriteInfoP);
slot = spriteInfoP->nextSlot;
}

}

COPY4
/* copy 4 pixels based on bits of the mask */
#define COPY4(q,p,m) \
switch ((m) & 0x0f)\
{ \
case 0x0: break;\
case 0x1: *(q+3) = *(p+3); break; \
case 0x2: *(q+2) = *(p+2); break; \
case 0x3: *(short*)(q+2) = *(short*)(p+2); break; \
case 0x4: *(q+1) = *(p+1); break; \
case 0x5: *(q+1) = *(p+1); *(q+3) = *(p+3); break;      \
case 0x6: *(short*)(q+1) = *(short*)(p+1); break; \
case 0x7: *(q+1) = *(p+1); \
*(short*)(q+2) = *(short*)(p+2); break;   \
case 0x8: *(q) = *(p); break;\
case 0x9: *(q) = *(p); *(q+3) = *(p+3); break;    \
case 0xA: *(q) = *(p); *(q+2) = *(p+2); break;    \
case 0xB: *(q) = *(p);   \
*(short*)(q+2) = *(short*)(p+2); break;   \
case 0xC: *(short*)(q) = *(short*)(p); break;     \
case 0xD: *(short*)(q) = *(short*)(p);\
*(q+3) = *(p+3); break;\
case 0xE: *(short*)(q) = *(short*)(p);\
*(q+2) = *(p+2); break;\
case 0xF: *(long*)(q) = *(long*)(p); break; \
}

COPY8
COPY4(q, p, mask >> 4)   \

DrawSprite
static void DrawSprite(short slot)
{
SpriteInfoPtr spriteInfoP;
short  numRows;
short  numCols;
register Ptr  p;
register Ptr  q;
short  srcRowBytes;
short  h, v;
short  i;
long   dstRowBytes;

spriteInfoP = &gSpriteInfo[slot];
h = spriteInfoP->position.h;
v = spriteInfoP->position.v;
numRows = spriteInfoP->height;
numCols = spriteInfoP->width;
p = (char *) &gSpritePixData[slot];

if (numCols >= 8)
{
srcRowBytes = 40 - numCols;
dstRowBytes = gOnDeckRowBytes - numCols + 8;
while (1)
{
while (1)
{
if (--i == 0)
break;
p += 8;
q += 8;
}
if (--numRows == 0)
break;
p += srcRowBytes;
q += dstRowBytes;
}
}
else
{
while (1)
{
if (--numRows == 0)
break;
p += 32;
q += gOnDeckRowBytes;
}
}
}

DrawNewSprites
static void DrawNewSprites(void)
{
register short  slot;
SpriteInfoPtr spriteInfoP;

slot = gFirstSpriteSlot;
while (slot >= 0)
{
register short  numRows;
register short  numCols;
register short  h;
register short  v;

spriteInfoP = &gSpriteInfo[slot];
if (spriteInfoP->status < 0)
goto nextSlot;  /* deleted, so skip it */
numRows = spriteInfoP->height;
numCols = spriteInfoP->width;
h = spriteInfoP->position.h;
v = spriteInfoP->position.v;
if (h + numCols <= 0 || h >= gWindowWidth
|| v + numRows <= 0 || v >= gWindowHeight)
goto nextSlot;  /* totally offscreen */

DrawSprite(slot);
nextSlot:
slot = spriteInfoP->nextSlot;
}
}

FastCopyChunk
/* count is a multiple of 4 in the range [4..44] */
static void FastCopyChunk(long *q, long *p,
short count, short rows)
{
register short  srcRowBytes;
register short  dstRowBytes;
register short  rowsLeft = rows;
register short  copy8 = count & 8;
register short  copy4 = count & 4;

srcRowBytes = gOnDeckRowBytes - count;
dstRowBytes = gScreenRowBytes - count;
if (count & 32)
{
while (rowsLeft > 0)
{
rowsLeft--;
*q++ = *p++;
*q++ = *p++;
*q++ = *p++;
*q++ = *p++;
*q++ = *p++;
*q++ = *p++;
*q++ = *p++;
*q++ = *p++;
if (copy8)
{
*q++ = *p++;
*q++ = *p++;
}
if (copy4)
*q++ = *p++;
p = (long *) (((Ptr) p) + srcRowBytes);
q = (long *) (((Ptr) q) + dstRowBytes);
}
}
else if (count & 16)
{
while (rowsLeft > 0)
{
rowsLeft--;
*q++ = *p++;
*q++ = *p++;
*q++ = *p++;
*q++ = *p++;
if (copy8)
{
*q++ = *p++;
*q++ = *p++;
}
if (copy4)
*q++ = *p++;
p = (long *) (((Ptr) p) + srcRowBytes);
q = (long *) (((Ptr) q) + dstRowBytes);
}
}
else
{
while (rowsLeft > 0)
{
rowsLeft--;
if (copy8)
{
*q++ = *p++;
*q++ = *p++;
}
if (copy4)
*q++ = *p++;
p = (long *) (((Ptr) p) + srcRowBytes);
q = (long *) (((Ptr) q) + dstRowBytes);
}
}
}

DrawNewSpritesToScreen

/* Here we do have to watch out for sprites that overlap the edges of the window.  We copy a rectangluar
region that includes the sprites previous and current positions.  We know they will be close sionce sprites
move at most 8 pixels per turn.
*/
static void DrawNewSpritesToScreen(void)
{
short  slot;
SpriteInfoPtr spriteInfoP;
short  numRows;
short  numCols;
register long   *p;
register long   *q;
short  hStart, hEnd;
short  vStart, vEnd;

slot = gFirstSpriteSlot;
while (slot >= 0)
{
spriteInfoP = &gSpriteInfo[slot];
numRows = spriteInfoP->height;
numCols = spriteInfoP->width;
if (spriteInfoP->position.h
< spriteInfoP->lastPosition.h)
{
hStart = spriteInfoP->position.h;
hEnd = spriteInfoP->lastPosition.h + numCols;
}
else
{
hStart = spriteInfoP->lastPosition.h;
hEnd = spriteInfoP->position.h + numCols;
}
if (hStart < 0)
hStart = 0;
else if (hEnd > gWindowWidth)
hEnd = gWindowWidth;
if (spriteInfoP->position.v
< spriteInfoP->lastPosition.v)
{
vStart = spriteInfoP->position.v;
vEnd = spriteInfoP->lastPosition.v + numRows;
}
else
{
vStart = spriteInfoP->lastPosition.v;
vEnd = spriteInfoP->position.v + numRows;
}
if (vStart < 0)
vStart = 0;
else if (vEnd > gWindowHeight)
vEnd = gWindowHeight;
hStart = hStart & -4;  /* make it a mult of 4 */
hEnd = (hEnd + 3) & -4;  /* make it a mult of 4 */

p = (long *) (gOnDeckRowAddr[vStart] + hStart);
q = (long *) (gScreenRowAddr[vStart] + hStart);

vEnd -= vStart; /* now it’s a count */
hEnd -= hStart; /* now it’s a count */
if (hEnd >= 0)
FastCopyChunk(q, p, hEnd, vEnd);

spriteInfoP->lastPosition = spriteInfoP->position;
slot = spriteInfoP->nextSlot;
}
}

{
EraseOldSprites();
DrawNewSprites();
DrawNewSpritesToScreen();
if (gDeletionCount != 0)
RemoveDeletedSprites();
}
```

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Box Sync gives you a hard-drive in the Cloud for online storage. Note: You must first sign up to use Box. What if the files you need are on your laptop -- but you're on the road with your iPhone? No... Read more
Audio Hijack 3.8.10 - Record and enhance...
Audio Hijack (was Audio Hijack Pro) drastically changes the way you use audio on your computer, giving you the freedom to listen to audio when you want and how you want. Record and enhance any audio... Read more
Direct Mail 6.0.1 - Create and send grea...
Direct Mail is an easy-to-use, fully-featured email marketing app purpose-built for macOS. Create, send, and track great looking email campaigns that get results. Start your newsletter by selecting... Read more

## Latest Forum Discussions

Hopefully Not Jared’s Last Show – The To...
My suspicions from last week were correct, and after my two kids tested positive for Covid last week both my wife and I have now tested positive as well. It seems you just can’t escape this stuff lately. Thankfully the two little ones are pretty... | Read more »
TouchArcade Game of the Week: ‘Micro RPG...
I feel like idle games are one of those perfect fits for the mobile platform. Not that they replace more involved gaming experiences when you’re in the mood for that, but they do fit in alongside other types of games just fine as a “go to" when you... | Read more »
Phantom Blade: Executioners is holding a small-scale technical test that lets players get first dibs on the KungFuPunk action RPG. Offered to selected players only, S-Game’s first Closed Beta Test will provide players with limited edition in-game... | Read more »
New ‘Warhammer 40,000: Tacticus’ Video S...
Back in September Snowprint Studios, who you may know from their previous Legend of Solgard or Rivengard, announced that they’d partnered up with Games Workshop to put out a new tactical game in the Warhammer 40,000 universe titled Warhammer 40,000... | Read more »
Hello gentle readers, and welcome to the SwitchArcade Round-Up for January 28th, 2022. We’ve got a bunch of new releases to look at today, with a few big hitters, a few mid-level diversions, and a healthy supply of compost. Since it’s Friday, we... | Read more »
S-Game has kicked off its first Closed Beta Test for Phantom Blade: Executioners, inviting a selected few to get first dibs on the upcoming KungFuPunk action RPG on mobile. The CBT officially begins this January 28th, and beta testers will receive... | Read more »
‘Infinite Galaxy’ First Anniversary: Cel...
Cultivating a new generation of valiant commanders across 240 countries worldwide, Infinite Galaxy has quenched players’ thirst to explore the vastness of space – and there are only more intergalactic adventures to embark on from here on out. Camel... | Read more »
War and Order: How to brave the cold in...
War and Order's 6th-anniversary celebrations are underway, and all in good time too - this season not only brings about fabulous festivities, but it also lets players experience the harsh winter in an entirely new way. [Read more] | Read more »
‘Hidden Folks+’ Is This Week’s New Apple...
The original Hidden Folks from Adriaan de Jongh is an excellent hidden objects game featuring hand drawn visuals. It is an absolute joy to play, and it has now released on Apple Arcade in the form of Hidden Folks+ () as an App Store great. If you’... | Read more »
Mini Metro’s First Big Update of 2022 Ad...
Last year saw great updates for Dinosaur Polo Club’s Mini Metro (\$3.99) which is also available on Apple Arcade as an App Store Great. | Read more »

## Price Scanner via MacPrices.net

Apple has clearance 2020 13″ MacBook Airs ava...
Apple has clearance, Certified Refurbished, 2020 13″ Intel-based MacBook Airs in stock today starting at only \$719 and up to \$370 off original MSRP. Each MacBook features a new outer case, comes with... Read more
The cheapest iPhones for sale today at Apple...
Apple has restocked Apple Certified Refurbished iPhone 8 models starting at only \$359. Each refurbished iPhone comes with a fresh external case, standard Apple 1-year warranty, and free shipping.... Read more
14″ MacBook Pro with Apple M1 Max CPU now in...
Looking for a new 14″ MacBook Pro with an Apple M1 Max CPU? Stock is finally trickling into Apple resellers. B&H has Silver 14″ M1 Max MacBook Pros in stock today for \$2899 including free 1-2 day... Read more
14″ MacBook Pros with Apple M1 Pro CPUs are i...
Amazon is reporting stock of 14″ MacBook Pros with M1 Pro CPUs today with a \$50 discount. Shipping is free, and delivery is available by February 1st for most configurations. Be sure to make your... Read more
Apple has restocked 13″ M1 MacBook Pros for \$...
Apple has restocked a full line of 13″ M1 MacBook Pros available Certified Refurbished, starting at only \$1099 and up to \$230 off original MSRP. These are the cheapest M1 MacBook Pros for sale today... Read more
Apple’s AirPods Max headphones are on sale fo...
Amazon has Silver, Blue, and Space Gray Apple AirPods Max headphones on sale today for \$100 off MSRP. Shipping is free, and all models are in stock today. Their price is the lowest currently... Read more
Open a new line of service at Verizon and get...
Verizon is giving away 64GB Apple iPhone 12 minis or your choice of an iPhone 11 to customers who choose one of these phones and open a new line of service. Offer is available online only, and no... Read more
Open-box 13″ M1 MacBook Airs now available st...
QuickShip Electronics has open-box return 13″ M1 MacBook Airs in stock and on sale for \$200-\$400 off MSRP on their eBay store right now with free express delivery. According to QuickShip, “The item... Read more
Verizon’s 2022 iPad promo: \$100-\$310 off any...
Verizon has cellular-capable iPads on sale for \$100-\$310 off MSRP when purchased with an Unlimited service plan. Sale price is applied to your account monthly over a 24 or 30 month period, depending... Read more
Sunday Sale: Apple AirPods are on sale for up...
Amazon has Apple AirPods on sale for \$10-\$100 off MSRP today, depending on the model. All are in stock today with free delivery: – AirPods Max headphones (Blue): \$449 \$100 off MSRP – AirPods Max... Read more

## Jobs Board

Registered Nurse (RN) Employee Health PSJH -...
…is calling for a Registered Nurse (RN) Employee Health PSJH to our location in Apple Valley, CA.** We are seeking a Registered Nurse (RN) Employee Health PSJH to be Read more
Systems Administrator - Pearson (United State...
…and troubleshoot Windows operating systems (workstation and server), laptop computers, Apple iPads, Chromebooks and printers** + **Administer and troubleshoot all Read more
IT Assistant Level 1- IT Desktop Support Anal...
…providing tier-1 or better IT help desk support in a large Windows and Apple environment * Experience using IT Service Desk Management Software * Knowledge of IT Read more
Human Resources Business Partner PSJH - Provi...
…**is calling a** **Human Resources Business Partner, PSJH** **to our location in Apple Valley, CA.** **Applicants that meet qualifications will receive a text with Read more
Manager Community Health Investment Programs...
…is calling a Manager Community Health Investment Programs PSJH to our location in Apple Valley, CA.** **Qualified candidates will be invited to do a self-paced video Read more