screen_savers/Nebula: Convert draw.S to C.

Hand-translated. I left the assembly in as comments for easy analysis,
I'll remove it in the next commit.

(I didn't do this on my own, I had help.)

src/add-ons/screen_savers/nebula/Draw.c

@@ -0,0 +1,148 @@
+// Hand-translated from x86 assembly.
+
+/* memshset (char *dst, int center_shade,int fixed_shade, int length_2) */
+/* dst is the *center* of the dst segment */
+/* center shade is the initial color (at center) (!! 8:8 also) */
+/* fixed_shade is the fixed point increment (8:8) */
+/* length_2 is the 1/2 length to set (to the left, and to the right) */
+
+/* a memaddshadedset function (or something like that ) */
+
+void memshset(char* dstParam, int center_shade, int fixed_shade, int half_length)
+{
+	unsigned char* dst;
+	unsigned char* source;
+	int offset;
+
+	if (half_length == 0)
+		return;
+
+//	movl	8(%ebp),%edi      /* dst */
+//	movl	12(%ebp),%eax	/* center_shade*/
+//	movl	16(%ebp),%ebx	  /* fixed_shade */
+//	movl	20(%ebp),%ecx	  /* half_length */
+//
+//@	orl		%ecx,%ecx
+//@	jz		2f
+//
+
+	dst = (unsigned char*)dstParam;
+	source = dst;
+//	movl	%edi,%esi
+	dst -= half_length; // Left segment
+//	subl	%ecx,%edi		/* %edi  left segment */
+	source += half_length; // Right segment
+//	addl	%ecx,%esi		/* %esi  right segment */
+	source++; // Don't overlap at middle
+//	incl	%esi			/* dont overlap at middle */
+//
+	offset = half_length;
+//	movl	%ecx,%edx
+	offset = -offset;
+//	negl	%edx
+	offset--; // For in-advance incl in loop
+//	decl	%edx			/* for in-advance incl in loop */
+
+	do {
+		int tmp;
+//1:
+		center_shade += fixed_shade; // Increment color.
+		center_shade &= 0xFFFF; // Mask so we can do overflow tests.
+//	addl	%ebx,%eax		/* increment color */
+		offset++;
+//	incl	%edx
+
+		tmp = dst[half_length] + (center_shade >> 8); // Increment left pixel.
+		//	addb	%ah,(%edi,%ecx)	/* increment  left pixel */
+		// Did it overflow?
+		if (tmp & 0xFF00) {
+		//	jc		3f				/* did overflow ? */
+			dst[half_length] = 255;
+//3:
+//	movb	$255,(%edi,%ecx)
+		} else {
+			dst[half_length] = tmp;
+		}
+
+
+		tmp = source[offset] + (center_shade >> 8); // Increment right pixel.
+		// Did it overflow?
+		if (tmp & 0xFF00) {
+			source[offset] = 255;
+//4:
+//	movb	$255,(%esi,%edx)
+//	decl	%ecx
+//	jnz		1b
+//
+//	popl	%ebx
+//	popl	%esi
+//	popl	%edi
+//
+//	leave
+//	ret
+		} else {
+			source[offset] = tmp;
+		}
+//	addb	%ah,(%esi,%edx) /* increment right pixel */
+//	jc		4f
+//
+	} while (--half_length != 0);
+//	decl	%ecx
+//	jnz		1b
+//
+//2:
+//	popl	%ebx
+//	popl	%esi
+//	popl	%edi
+//
+//	leave
+//	ret
+}
+
+
+/* do the "motion blur" (actually the pixel fading) */
+void mblur(char* srcParam, int nbpixels)
+{
+//	movl	8(%ebp),%edi      /* dst */
+//	movl	12(%ebp),%ecx     /* number */
+	unsigned int clear1UpperBit = 0x7f7f7f7f;
+	unsigned int clear3UpperBits = 0x1f1f1f1f;
+	unsigned long* src = (unsigned long*)srcParam;
+//	movl	$0x7f7f7f7f,%edx  /* clear 1 upper bits */
+//	movl	$0x1f1f1f1f,%esi  /* clear 3 upper bits */
+
+	if ((nbpixels >>= 2) == 0)
+	//	shrl	$2,%ecx
+		return;
+		//	jz	2f
+//
+	do {
+//1:
+		long eax, ebx;
+		eax = *src;
+	//	movl	(%edi),%eax
+		src++;
+	//	addl	$4,%edi
+	//
+		ebx = eax;
+	//	movl	%eax,%ebx
+		eax >>= 1;
+	//	shrl	$1,%eax
+	//
+	//
+		ebx >>= 3;
+	//	shrl	$3,%ebx
+		eax &= clear1UpperBit;
+	//	andl	%edx,%eax
+	//
+		ebx &= clear3UpperBits;
+	//	andl	%esi,%ebx
+		eax += ebx;
+	//	addl	%ebx,%eax
+	//
+		src[-1] = eax;
+	//	movl	%eax,-4(%edi)
+	} while (--nbpixels != 0);
+	//	decl	%ecx
+	//	jnz	1b
+}

src/add-ons/screen_savers/nebula/Nebula.cpp

@@ -33,8 +33,7 @@ float presin[512];
 typedef unsigned short word;
 
 extern "C" {
-	void memshset(char *dst, int center_shade,int fixed_shade, int length_2);
+	#include "Draw.c"
-	void mblur(char *src, int nbpixels);
 
 	void draw_stars320(char *, char);
 	void draw_stars512(char *, char);
@@ -173,19 +172,19 @@ drawshdisk(int x0, int y0, int r)
 		//gBuffer8[x0+W*y0] = 10+r*5;
 		return;
 	}
-	
+
 	if (r < SLIMIT+SRANGE)
 		r = ((r-SLIMIT)*SLIMIT)/SRANGE+1;
 
 	y = ly = r;     /* AAaargh */
 	delta = 3-2*r;
 
-	do {	
+	do {
 		if (y != ly) {
 			/* dont overlap these lines */
 			c = ((r-y+1)<<13)/r;
 			d = -c/(x+1);
-			
+
 			if (y == x+1)		/* this would overlap with the next x lines */
 				goto TOTO;		/* WHY NOT */
 
@@ -193,11 +192,11 @@ drawshdisk(int x0, int y0, int r)
 				(unsigned int)(x) < M   <=>  0<=x<H
 				(because if x<0, then (unsigned)(x) = 2**32-|x| which is
 				BIG and thus >H )
-			
+
 				This is clearly a stupid, unmaintanable, unreadable "optimization".
 				But i like it :)
 			*/
-			if ((uint32)(y0-y-1) < gHeight-3)   
+			if ((uint32)(y0-y-1) < gHeight-3)
 				memshset(&gBuffer8[x0 + gWidth*(y0-y+1)] ,c,d, x);
 			if ((uint32)(y0+y-1) < gHeight-3)
 				memshset(&gBuffer8[x0 + gWidth*(y0+y)] ,c,d, x);
@@ -219,7 +218,7 @@ drawshdisk(int x0, int y0, int r)
 			y--;
 		}
 		x++;
-	} while (x < y);	
+	} while (x < y);
 }
 
 
@@ -240,8 +239,8 @@ drawGalaxy()
 	(independant of processor speed)
 	*/
 	static bigtime_t firstTime = system_time();
-	t = ((double)gSpeed * system_time()-firstTime)/1000000.0; //opti_scale_time(0.418, &demo_elapsed_time);  
+	t = ((double)gSpeed * system_time()-firstTime)/1000000.0; //opti_scale_time(0.418, &demo_elapsed_time);
-	
+
 	a = 0.9*t;
 	b = t;
 	c = 1.1*t;
@@ -255,12 +254,12 @@ drawGalaxy()
 	oa = 140 * osin(a);
 	ob = 140 * ocos(b);
 	oc = 240 * osin(c);
-	
+
 	if (gMotionBlur) {
 		/* mblur does something like that:
 		 * (or did, perhaps it's another version!..)
-	
+
-		for (i=0; i<W*H; i++)   
+		for (i=0; i<W*H; i++)
 			gBuffer8[i]= (gBuffer8[i]>>3) + (gBuffer8[i]>>1);
 		*/
 		mblur (gBuffer8, gWidth*gHeight);
@@ -314,24 +313,24 @@ setPalette()
 		case 1:		// blue
 			for (i = 0; i < 30; i++)
 				gPalette[i] = (uint8)(i*8/10); // << 16 | (uint8)(i*6/10) << 8; // | (uint8)(i*3/10);
-			
+
 			for (i = 30; i < 256; i++) {
 				uint8 b = (i);
 				uint8 g = (i*i >> 8); //(i*8/10);
 				uint8 r = i >= 240 ? (i-240) << 3 : 0; //(i*2/10);
-		
+
 				gPalette[i] = ((r << 16) | (g << 8) | (b));
 			}
 			break;
 		case 2:		// red
 			for (i = 0;i < 128;i++)
 				gPalette[i] = (uint8)i << 16; // << 16 | (uint8)(i*6/10) << 8; // | (uint8)(i*3/10);
-			
+
 			for (i = 128;i < 256;i++)
-			{	
+			{
 				uint8 r = i;
 				uint8 c = (uint8)((cos((i-256) / 42.0)*0.5 + 0.5)*225);
-		
+
 				gPalette[i] = ((r << 16) | (c << 8) | c);
 			}
 /*			for (i = 192;i < 224;i++)
@@ -413,12 +412,12 @@ class SimpleSlider : public BSlider {
 		};
 
 		char *UpdateText() const
-		{ 
+		{
 			sprintf(fText, "%s: %d", fLabel, Value());
 
 			return fText;
 		};
-	
+
 	private:
 		mutable char fText[32];
 		const char *fLabel;
@@ -432,10 +431,10 @@ class SimpleSlider : public BSlider {
 class SettingsView : public BView {
 	public:
 		SettingsView(BRect frame);
-		
+
 		virtual void AttachedToWindow();
 		virtual void MessageReceived(BMessage *msg);
-	
+
 	private:
 		BMenuField *fWidthMenu,*fColorMenu,*fBorderMenu;
 		BCheckBox *fMotionCheck;
@@ -463,7 +462,7 @@ SettingsView::AttachedToWindow()
 
 	BRect rect(10,0,0,25);
 	rect.right = Bounds().right;
-	
+
 	BStringView *string = new BStringView(rect,B_EMPTY_STRING,"Nebula");
 	string->SetFontSize(18.0);
 	AddChild(string);
@@ -472,7 +471,7 @@ SettingsView::AttachedToWindow()
 	string = new BStringView(rect,B_EMPTY_STRING,VERSION_STRING);
 	AddChild(string);
 
-//	rect.OffsetBy(0,height+5);	
+//	rect.OffsetBy(0,height+5);
 	rect.left = 10;  rect.top = 27;  rect.bottom = 17+height;
 	string = new BStringView(rect,B_EMPTY_STRING,"© 2001-2004 pinc Software, Axel Dörfler.");
 	string->SetAlignment(B_ALIGN_CENTER);
@@ -629,7 +628,7 @@ Nebula::Nebula(BMessage *message, image_id id)
 		gSettingsWidth = 320;
 	if (gMaxFramesPerSecond < 1.f)
 		gMaxFramesPerSecond = 40.0f;
-	
+
 	gScreenSaver = this;
 }
 

src/add-ons/screen_savers/nebula/draw.S

@@ -1,136 +0,0 @@
-
-.text
-
-/* memshset (char *dst, int center_shade,int fixed_shade, int length_2) */
-/* dst is the *center* of the dst segment */
-/* center shade is the initial color (at center) (!! 8:8 also) */
-/* fixed_shade is the fixed point increment (8:8) */
-/* length_2 is the 1/2 length to set (to the left, and to the right) */
-
-/* a memaddshadedset function (or something like that ) */
-		
-.globl memshset
-.type  memshset,@function
-
-
-memshset:
-	pushl	%ebp
-	movl	%esp,%ebp
-	
-	pushl	%edi		/* registres a sauvegarder (convention gcc) */
-	pushl	%esi
-	pushl	%ebx
-
-	movl	8(%ebp),%edi      /* dst */
-	movl	12(%ebp),%eax
-	movl	16(%ebp),%ebx	  /* fixed point */
-	movl	20(%ebp),%ecx	  /* half length */
-
-	orl		%ecx,%ecx
-	jz		2f
-
-	movl	%edi,%esi
-	subl	%ecx,%edi		/* %edi  left segment */
-	addl	%ecx,%esi		/* %esi  right segment */
-	incl	%esi			/* dont overlap at middle */
-	
-	movl	%ecx,%edx
-	negl	%edx
-	decl	%edx			/* for in-advance incl in loop */
-1:
-	addl	%ebx,%eax		/* increment color */
-	incl	%edx
-	
-	addb	%ah,(%edi,%ecx)	/* increment  left pixel */
-	jc		3f				/* did overflow ? */
-	
-	addb	%ah,(%esi,%edx) /* increment right pixel */
-	jc		4f
-
-	decl	%ecx
-	jnz		1b
-
-2:	
-	popl	%ebx
-	popl	%esi
-	popl	%edi
-
-	leave
-	ret
-/* function goes on (several exit points): */
-3:
-	movb	$255,(%edi,%ecx)
-	addb	%ah,(%esi,%edx)        /* we recopy all the code.. to avoid jmps   (hmm some asm guru here :	 is it really efficient ?.. */
-	jc		4f
-	decl	%ecx
-	jnz		1b
-	
-	popl	%ebx
-	popl	%esi
-	popl	%edi
-
-	leave
-	ret
-
-4:
-	movb	$255,(%esi,%edx)
-	decl	%ecx
-	jnz		1b
-	
-	popl	%ebx
-	popl	%esi
-	popl	%edi
-
-	leave
-	ret
-/* function really stops here  */
-
-
-/*********************************** motion blur **********************************/
-
-/* do the "motion blur" (actually the pixel fading) */
-.globl  mblur
-.type   mblur,@function
-	
-mblur:	
-	pushl	%ebp
-	movl	%esp,%ebp
-	
-	pushl	%edi
-	pushl	%esi
-	pushl	%ebx
-	
-	movl	8(%ebp),%edi      /* dst */
-	movl	12(%ebp),%ecx     /* number */
-	movl	$0x7f7f7f7f,%edx  /* clear 1 upper bits */
-	movl	$0x1f1f1f1f,%esi  /* clear 3 upper bits */
-	shrl	$2,%ecx
-	jz	2f
-
-1:
-	movl	(%edi),%eax
-	addl	$4,%edi
-	
-	movl	%eax,%ebx
-	shrl	$1,%eax
-
-	
-	shrl	$3,%ebx
-	andl	%edx,%eax
-	
-	andl	%esi,%ebx
-	addl	%ebx,%eax
-
-	decl	%ecx
-	movl	%eax,-4(%edi)
-	
-
-	jnz	1b
-
-
-2:
-	popl	%ebx
-	popl	%esi
-	popl	%edi
-	leave
-	ret

src/add-ons/screen_savers/nebula/makefile

@@ -6,7 +6,7 @@ CFLAGS	= -O3 -ffast-math -funroll-loops -fomit-frame-pointer -fexpensive-optimiz
 LIBS	= -lbe -lscreensaver
 NAME	= Nebula
 FILES 	= Nebula
-ASMFILES = draw
+ASMFILES =
 STARFILE = draw_stars
 STARWIDTHS = 320 512 576 640 800 1024 1152 1280 1400 1600
 OBJDIR	= obj.x86