From bd7800913ecc8740c3c2f99d9c0ccdb8358462a8 Mon Sep 17 00:00:00 2001
From: Christopher Lu <lu@stop.(none)>
Date: Wed, 9 Jul 2008 00:24:51 -0400
Subject: [PATCH] added mandelsim.c

---
 mandelsim.c | 137 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 137 insertions(+)
 create mode 100644 mandelsim.c

diff --git a/mandelsim.c b/mandelsim.c
new file mode 100644
index 0000000..16bdf46
--- /dev/null
+++ b/mandelsim.c
@@ -0,0 +1,137 @@
+#include <stdio.h>
+#include <SDL/SDL.h>
+
+#define XRES 640
+#define YRES 480
+#define MAX_ITER 66
+#define MAXNUM 0x8000
+#define BITS 14
+#define BAIL (1 << (BITS + 1))
+#define BAIL_A (1 << BITS)
+
+SDL_Surface *screen;
+typedef unsigned short num_t;
+
+typedef struct {
+	num_t mag;
+	num_t sig;
+} sigmag_t;
+
+typedef struct {
+	sigmag_t r;
+	sigmag_t i;
+} cplx_t;
+
+static inline cplx_t convert(num_t x, num_t y)
+{
+	sigmag_t r, i;
+	r.mag = x > MAXNUM ? -x : x;
+	r.sig = x > MAXNUM ? 1 : 0;
+	i.mag = y > MAXNUM ? -y : y;
+	i.sig = y > MAXNUM ? 1 : 0;
+	cplx_t res = {r, i};
+//	printf("convert: output: x = %d, y = %d\n", res.r.mag, res.i.mag);
+	return res;
+}
+
+static inline sigmag_t mul(sigmag_t x, sigmag_t y)
+{
+	num_t xm = x.mag;
+	num_t ym = y.mag;
+	num_t mag = 
+	            (ym & 0x2000 ? xm       : 0) +
+	            (ym & 0x1000 ? xm >> 1  : 0) +
+	            (ym & 0x0800 ? xm >> 2  : 0) +
+	            (ym & 0x0400 ? xm >> 3  : 0) +
+	            (ym & 0x0200 ? xm >> 4  : 0) +
+	            (ym & 0x0100 ? xm >> 5  : 0) +
+	            (ym & 0x0080 ? xm >> 6  : 0) +
+	            (ym & 0x0040 ? xm >> 7  : 0) +
+	            (ym & 0x0020 ? xm >> 8  : 0) +
+	            (ym & 0x0010 ? xm >> 9  : 0) +
+	            (ym & 0x0008 ? xm >> 10 : 0) +
+	            (ym & 0x0004 ? xm >> 11 : 0) +
+	            (ym & 0x0002 ? xm >> 12 : 0) +
+	            (ym & 0x0001 ? xm >> 13 : 0);
+
+	num_t sig = x.sig ^ y.sig;
+	sigmag_t res = {mag, sig};
+	return res;
+}
+
+static inline unsigned int calc_piqsl(num_t x, num_t y)
+{
+//	printf("calc_piqsl: x = %d, y = %d ############################ \n", x, y);
+	unsigned int i;
+	cplx_t c = convert(x, y);
+	cplx_t z = c;
+//	printf("xmag = %d, xsig = %d, ymag = %d, ysig = %d\n", c.r.mag, c.r.sig, c.i.mag, c.i.sig);
+	for(i = 0; i < MAX_ITER; i++) {
+		sigmag_t r2 = mul(z.r, z.r);
+		sigmag_t i2 = mul(z.i, z.i);
+		sigmag_t ri = mul(z.r, z.i);
+//		printf("r2mag: %d  i2mag: %d  i: %d\n", r2.mag, i2.mag, i);
+		if((r2.mag + i2.mag) & BAIL || z.r.mag & BAIL   || z.i.mag & BAIL 
+		                            || z.r.mag & BAIL_A || z.i.mag & BAIL_A) {
+			break;
+		}
+		num_t rmag = r2.mag - i2.mag + (c.r.sig ? -c.r.mag : c.r.mag);
+		num_t imag = (ri.sig ? -ri.mag << 1 : ri.mag << 1) + (c.i.sig ? -c.i.mag : c.i.mag);
+		z = convert(rmag, imag);
+	}
+
+//	printf("bailed at %d\n", i);
+	return (i == MAX_ITER ? 0 : i);
+}
+
+void run_mandel()
+{
+	num_t i, j;
+	int dick = 160;
+	int zoom = 4;
+	unsigned int res, *p;
+
+	SDL_LockSurface(screen);
+	p = screen->pixels;
+
+	for(i = 0; i < XRES; i++) {
+		for(j = 0; j <3 *dick; j++) {
+			res = calc_piqsl((i - XRES/2) << zoom, (j - YRES/2) << zoom);
+			res = res == 0 ? 0 : MAX_ITER - res - 3;
+			p[i+j*XRES] = ((res & 0x1) << 23) | ((res & 0x8)  << 18) | ((res & 0x40) << 13) |
+			              ((res & 0x2) << 14) | ((res & 0x10) <<  9) | ((res & 0x80) << 4) |
+				      ((res & 0x4) <<  5) | ((res & 0x20));
+			
+		}
+	}
+
+	SDL_UnlockSurface(screen);
+	SDL_Flip(screen);
+}
+
+int main()
+{
+	SDL_Event ev;
+	screen = NULL;
+	if(SDL_Init(SDL_INIT_VIDEO) < 0) {
+		printf("Video init failed.\n");
+		return 1;
+	}
+
+	screen = SDL_SetVideoMode(XRES, YRES, 32, SDL_SWSURFACE);
+	if(!screen) {
+		printf("Screen init failed.\n");
+		return 1;
+	}
+	atexit(SDL_Quit);
+
+	run_mandel();
+	while(SDL_WaitEvent(&ev)) {
+		switch(ev.type) {
+		case SDL_QUIT: exit(0);
+		default: break;
+		}
+	}
+
+	return 0;
+}
-- 
2.39.2