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14 * $Source: /cvs/cvsroot/d2x/maths/fixc.c,v $
17 * $Date: 2001-01-31 15:18:04 $
19 * C version of fixed point library
21 * $Log: not supported by cvs2svn $
22 * Revision 1.1.1.1 2001/01/19 03:29:58 bradleyb
25 * Revision 1.3 1999/10/18 00:31:01 donut
26 * more alpha fixes from Falk Hueffner
28 * Revision 1.2 1999/08/05 22:53:41 sekmu
30 * D3D patch(es) from ADB
32 * Revision 1.1.1.1 1999/06/14 22:13:35 donut
33 * Import of d1x 1.37 source.
35 * Revision 1.7 1995/09/22 14:08:16 allender
36 * fixed fix_atan2 to work correctly with doubles
38 * Revision 1.6 1995/08/31 15:43:49 allender
39 * *** empty log message ***
41 * Revision 1.5 1995/07/05 16:15:15 allender
42 * make fixmuldiv use doubles for PPC implementation
44 * Revision 1.4 1995/05/15 13:57:36 allender
45 * make fixmuldiv compile when compiling under 68k
47 * Revision 1.3 1995/05/11 13:02:59 allender
48 * some routines are now in assembly
50 * Revision 1.2 1995/05/04 20:04:45 allender
51 * use MPW fixdiv if compiling with MPW (why did I do this?)
53 * Revision 1.1 1995/04/17 11:37:54 allender
58 * Revision 1.1 1995/03/08 18:55:09 matt
69 static char rcsid[] = "$Id: fixc.c,v 1.2 2001-01-31 15:18:04 bradleyb Exp $";
81 #pragma message ("warning: FIX NOT INLINED")
83 #warning "FIX NOT INLINED"
88 extern ubyte guess_table[];
89 extern short sincos_table[];
90 extern ushort asin_table[];
91 extern ushort acos_table[];
92 extern fix isqrt_guess_table[];
95 void fixquadnegate(quad *q)
98 q->high = 0 - q->high - (q->low != 0);
101 //multiply two ints & add 64-bit result to 64-bit sum
102 void fixmulaccum(quad *q,fix a,fix b)
105 u_int32_t ah,al,bh,bl;
111 aa = labs(a); bb = labs(b);
113 ah = aa>>16; al = aa&0xffff;
114 bh = bb>>16; bl = bb&0xffff;
123 if (q->low < old) q->high++;
127 if (q->low < old) q->high++;
129 q->high += ah*bh + (t>>16) + c;
136 //extract a fix from a quad product
137 fix fixquadadjust(quad *q)
139 return (q->high<<16) + (q->low>>16);
143 #define EPSILON (F1_0/100)
146 #define QLONG __int64
148 #define QLONG long long
152 fix fixmul(fix a, fix b) {
153 /* return (fix)(((double)a*(double)b)/65536.0);*/
155 asm("imul %%edx; shrd $16,%%edx,%%eax" : "=a" (ret) : "a" (a), "d" (b) : "%edx");
157 return (fix)((((QLONG)a)*b) >> 16);
160 fix fixdiv(fix a, fix b)
162 /* return (fix)(((double)a * 65536.0) / (double)b);*/
163 return (fix)((((QLONG)a) << 16)/b);
165 asm("mov %%eax,%%edx; sar $16,%%edx; shl $16,%%eax; idiv %%ebx" : "=a" (ret) : "a" (a), "b" (b) : "%edx");
169 fix fixmuldiv(fix a, fix b, fix c)
172 asm("imul %%edx; idiv %%ebx" : "=a" (ret) : "a" (a), "d" (b), "b" (c) : "%edx");
177 d = (double)a * (double) b;
178 return (fix)(d / (double) c);
180 return (fix)((((QLONG)a)*b)/c);
184 //given cos & sin of an angle, return that angle.
185 //parms need not be normalized, that is, the ratio of the parms cos/sin must
186 //equal the ratio of the actual cos & sin for the result angle, but the parms
187 //need not be the actual cos & sin.
188 //NOTE: this is different from the standard C atan2, since it is left-handed.
190 fixang fix_atan2(fix cos,fix sin)
192 double d, dsin, dcos;
195 //Assert(!(cos==0 && sin==0));
197 //find smaller of two
201 d = sqrt((dsin * dsin) + (dcos * dcos));
206 if (labs(sin) < labs(cos)) { //sin is smaller, use arcsin
207 t = fix_asin((fix)((dsin / d) * 65536.0));
213 t = fix_acos((fix)((dcos / d) * 65536.0));
221 //divide a quad by a fix, returning a fix
222 int32_t fixdivquadlong(u_int32_t nl,u_int32_t nh,u_int32_t d)
232 Q = ((nh&0x80000000)!=0);
233 M = ((d&0x80000000)!=0);
238 for (i=0; i<32; i++ ) {
242 T = ((nl&0x80000000L)!=0);
248 Q = (unsigned char)((0x80000000L & nh) != 0 );
249 nh = (nh << 1) | (u_int32_t)T;
257 Q = (unsigned char)(tmp1 == 0);
260 Q = (unsigned char)((0x80000000L & nh) != 0 );
261 nh = (nh << 1) | (u_int32_t)T;
269 Q = (unsigned char)(tmp1 == 0);
277 for (i=0; i<32; i++ ) {
281 T = ((nl&0x80000000L)!=0);
287 Q = (unsigned char)((0x80000000L & nh) != 0 );
288 nh = (nh << 1) | (u_int32_t)T;
296 Q = (unsigned char)(tmp1 == 0);
299 Q = (unsigned char)((0x80000000L & nh) != 0 );
300 nh = (nh << 1) | (u_int32_t)T;
308 Q = (unsigned char)(tmp1 == 0);
320 unsigned int fixdivquadlongu(uint nl, uint nh, uint d)
322 return fixdivquadlong((u_int32_t) nl,(u_int32_t) nh,(u_int32_t) d);
325 int32_t fixdivquadlong(u_int32_t nl,u_int32_t nh,u_int32_t d) {
329 :"a" (nl), "d" (nh), "r" (d)
334 static inline u_int32_t fixdivquadlongu(u_int32_t nl,u_int32_t nh,u_int32_t d) {
338 :"a" (nl), "d" (nh), "r" (d)
345 u_int32_t quad_sqrt(u_int32_t low,int32_t high)
354 if (high==0 && (int32_t)low>=0)
355 return long_sqrt((int32_t)low);
357 if (high & 0xff000000) {
358 cnt=12+16; i = high >> 24;
359 } else if (high & 0xff0000) {
360 cnt=8+16; i = high >> 16;
361 } else if (high & 0xff00) {
362 cnt=4+16; i = high >> 8;
367 r = guess_table[i]<<cnt;
369 //quad loop usually executed 4 times
371 r = (fixdivquadlongu(low,high,r)+r)/2;
372 r = (fixdivquadlongu(low,high,r)+r)/2;
373 r = (fixdivquadlongu(low,high,r)+r)/2;
378 t = fixdivquadlongu(low,high,r);
385 } while (!(r==t || r==old_r));
387 t = fixdivquadlongu(low,high,r);
388 //edited 05/17/99 Matt Mueller - tq.high is undefined here.. so set them to = 0
391 fixmulaccum(&tq,r,t);
392 if (tq.low!=low || tq.high!=high)
398 //computes the square root of a long, returning a short
399 ushort long_sqrt(int32_t a)
408 else if (a & 0xff0000)
415 r = guess_table[(a>>cnt)&0xff]<<cnt;
417 //the loop nearly always executes 3 times, so we'll unroll it 2 times and
418 //not do any checking until after the third time. By my calcutations, the
419 //loop is executed 2 times in 99.97% of cases, 3 times in 93.65% of cases,
420 //four times in 16.18% of cases, and five times in 0.44% of cases. It never
421 //executes more than five times. By timing, I determined that is is faster
422 //to always execute three times and not check for termination the first two
423 //times through. This means that in 93.65% of cases, we save 6 cmp/jcc pairs,
424 //and in 6.35% of cases we do an extra divide. In real life, these numbers
425 //might not be the same.
440 } while (!(r==t || r==old_r));
448 //computes the square root of a fix, returning a fix
451 return ((fix) long_sqrt(a)) << 8;
455 //compute sine and cosine of an angle, filling in the variables
456 //either of the pointers can be NULL
458 void fix_sincos(fix a,fix *s,fix *c)
466 ss = sincos_table[i];
467 if (s) *s = (ss + (((sincos_table[i+1] - ss) * f)>>8))<<2;
469 cc = sincos_table[i+64];
470 if (c) *c = (cc + (((sincos_table[i+64+1] - cc) * f)>>8))<<2;
473 //compute sine and cosine of an angle, filling in the variables
474 //either of the pointers can be NULL
476 void fix_fastsincos(fix a,fix *s,fix *c)
482 if (s) *s = sincos_table[i] << 2;
483 if (c) *c = sincos_table[i+64] << 2;
486 //compute inverse sine
487 fixang fix_asin(fix v)
494 if (vv >= f1_0) //check for out of range
501 aa = aa + (((asin_table[i+1] - aa) * f)>>8);
509 //compute inverse cosine
510 fixang fix_acos(fix v)
517 if (vv >= f1_0) //check for out of range
524 aa = aa + (((acos_table[i+1] - aa) * f)>>8);
532 #define TABLE_SIZE 1024
534 //for passed value a, returns 1/sqrt(a)
535 fix fix_isqrt( fix a )
541 if ( a == 0 ) return 0;
543 while( b >= TABLE_SIZE ) {
548 //printf( "Count = %d (%d>>%d)\n", cnt, b, (cnt+1)/2 );
549 r = isqrt_guess_table[b] >> ((cnt+1)/2);
551 //printf( "Initial r = %d\n", r );
553 for (i=0; i<3; i++ ) {
555 r = fixmul( ( (3*65536) - fixmul(fixmul(r,r),a) ), r) / 2;
556 //printf( "r %d = %d\n", i, r );
557 if ( old_r >= r ) return (r+old_r)/2;