diff options
Diffstat (limited to 'semestr-3/anm/cordic/cordic.cpp')
| -rw-r--r-- | semestr-3/anm/cordic/cordic.cpp | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/semestr-3/anm/cordic/cordic.cpp b/semestr-3/anm/cordic/cordic.cpp new file mode 100644 index 0000000..b0dfd39 --- /dev/null +++ b/semestr-3/anm/cordic/cordic.cpp @@ -0,0 +1,189 @@ +#include <stdio.h>
+#include <math.h>
+//#define M_PI 3.1415926536897932384626
+int main(int argc, char **argv)
+{
+ FILE *f;
+ char tname[50], cname[10];
+ int n, n2, mp2, niter, bits, t;
+ double F, A, mul, tmul; // CORDIC gain, convergence angle, multiplication factor
+ printf("0)circular, 1)linear, 2)hyperbolic? ");
+ scanf("%d", &t);
+ switch (t)
+ {
+ case 0:
+ sprintf(cname, "%s", "");
+ break;
+ case 1:
+ sprintf(cname, "%s", "_LIN");
+ break;
+ case 2:
+ sprintf(cname, "%s", "_HYPER");
+ break;
+ }
+ sprintf(tname, "CORDICtable%s.c", cname);
+ if (NULL == (f = fopen(tname, "wt")))
+ {
+ printf("cannot write to %s\n", tname);
+ return 0;
+ }
+
+ printf("number of bits for mantissa (e.g. 30)? ");
+ scanf("%d", &bits);
+ printf("0) mul factor is 2^n (easier output scaling), or\n"
+ "1) 2pi is 2^n (easier implementation)\n ? ");
+ scanf("%d", &mp2);
+ printf("suggested multiplication factor ");
+ if (mp2 == 0)
+ {
+ tmul = (double)(1 << (bits - 3));
+ printf("2^%d = %f\n", bits - 3, tmul);
+ }
+ else
+ {
+ tmul = (double)(1 << (bits - 2)) / M_PI;
+ printf("2^%d/pi = %f\n", bits - 2, tmul);
+ }
+ printf("multiplication factor (0 for suggested)? ");
+ scanf("%lf", &mul);
+ if (mul < 0.1)
+ {
+ mul = tmul;
+ printf("%f\n", mul);
+ }
+ else
+ mp2 = -1; // custom mul factor
+ switch (t)
+ {
+ case 0:
+ for (n = 0; n < bits; n++)
+ if ((int)round(atan(pow(2.0, (double)(-n))) * mul) == 0)
+ break;
+ break;
+ case 1:
+ for (n = 0; n < bits; n++)
+ if ((int)round((pow(2.0, (double)(-n))) * mul) == 0)
+ break;
+ break;
+ case 2:
+ for (n = 1, n2 = 4; n < bits;)
+ {
+ if ((int)round(atanh(pow(2.0, (double)(-n))) * mul) == 0)
+ break;
+ if (n == n2)
+ n2 = 3 * n + 1;
+ else
+ n++;
+ }
+ break;
+ }
+ printf("iterations (up to %d)? ", n);
+ scanf("%d", &niter);
+
+ F = 1.0;
+ A = 0.0;
+ switch (t)
+ {
+ case 0:
+ for (n = 0; n < niter; n++)
+ {
+ F = F * sqrt(1 + pow(2.0, -2.0 * n));
+ A += atan(pow(2.0, (double)(-n)));
+ }
+ break;
+ case 1:
+ for (n = 0; n < niter; n++)
+ {
+ F = F * sqrt(1);
+ A += (pow(2.0, (double)(-n)));
+ }
+ break;
+ case 2:
+ for (n = 1, n2 = 4; n < niter;)
+ {
+ F = F * sqrt(1 - pow(2.0, -2.0 * n));
+ A += atanh(pow(2.0, (double)(-n)));
+ if (n == n2)
+ n2 = 3 * n + 1;
+ else
+ n++;
+ }
+ break;
+ }
+
+ fprintf(f, "//CORDIC%s, %d bits, %d iterations\n", cname, bits, niter);
+ fprintf(f, "// 1.0 = %f multiplication factor\n", mul);
+ switch (t)
+ {
+ case 0:
+ fprintf(f, "// A = %lf convergence angle "
+ "(limit is 1.7432866 = 99.9deg)\n",
+ A);
+ fprintf(f, "// F = %lf gain (limit is 1.64676025812107)\n", F);
+ fprintf(f, "// 1/F = %lf inverse gain (limit is 0.607252935008881)\n", 1.0 / F);
+ break;
+ case 1:
+ fprintf(f, "// A = %lf convergence angle (limit is 2)\n", A);
+ fprintf(f, "// F = %lf gain (limit is 1.0)\n", F);
+ fprintf(f, "// 1/F = %lf inverse gain (limit is 1.0)\n", 1.0 / F);
+ break;
+ case 2:
+ fprintf(f, "// A = %lf convergence angle "
+ "(limit is 1.1181730 = 64.0deg)\n",
+ A);
+ fprintf(f, "// F = %lf gain (limit is 0.82978162013890)\n", F);
+ fprintf(f, "// 1/F = %lf inverse gain (limit is 1.20513635844646)\n", 1.0 / F);
+ break;
+ }
+ fprintf(f, "// pi = %lf (3.1415926536897932384626)\n", M_PI);
+ fprintf(f, "\n");
+ fprintf(f, "#define CORDIC%s_A %f // CORDIC convergence angle A\n", cname, A);
+ fprintf(f, "#define CORDIC%s_F 0x%08X // CORDIC gain F\n",
+ cname, (int)round(mul * F));
+ fprintf(f, "#define CORDIC%s_1F 0x%08X // CORDIC inverse gain 1/F\n",
+ cname, (int)round(mul / F));
+ fprintf(f, "#define CORDIC%s_HALFPI 0x%08X\n", cname, (int)round(mul * (M_PI / 2.0)));
+ fprintf(f, "#define CORDIC%s_PI 0x%08X\n", cname, (int)round(mul * (M_PI)));
+ fprintf(f, "#define CORDIC%s_TWOPI 0x%08X\n", cname, (int)round(mul * (2.0 * M_PI)));
+ fprintf(f, "#define CORDIC%s_MUL %f // CORDIC multiplication factor M", cname, mul);
+ switch (mp2)
+ {
+ case 0:
+ fprintf(f, " = 2^%d\n", bits - 3);
+ break;
+ case 1:
+ fprintf(f, " = 2^%d/pi\n", bits - 2);
+ break;
+ default:
+ fprintf(f, "\n");
+ break;
+ }
+ fprintf(f, "#define CORDIC%s_MAXITER %d\n\n", cname, niter);
+ fprintf(f, "int CORDIC%s_ZTBL[] = {", cname);
+ for (n = 0; n < niter; n++)
+ {
+ if ((n % 8) == 0)
+ fprintf(f, "\n ");
+ switch (t)
+ {
+ case 0:
+ fprintf(f, "0x%08X", (int)round(atan(pow(2.0, (double)(-n))) * mul));
+ break;
+ case 1:
+ fprintf(f, "0x%08X", (int)round((pow(2.0, (double)(-n))) * mul));
+ break;
+ case 2:
+ n = n == 0 ? 1 : n;
+ fprintf(f, "0x%08X", (int)round(atanh(pow(2.0, (double)(-n))) * mul));
+ break;
+ }
+ if (n < (niter - 1))
+ fprintf(f, ", ");
+ else
+ fprintf(f, " ");
+ }
+ fprintf(f, "};\n\n");
+ fclose(f);
+ printf("table written to %s\n", tname);
+ return 0;
+}
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