87 lines
1.5 KiB
C
87 lines
1.5 KiB
C
#include "../io_reg.h"
|
|
#include "uprintf.h"
|
|
|
|
#include <stdint.h>
|
|
|
|
void put_char(char c)
|
|
{
|
|
IO_REG_CONSOLE = c | IO_REG_CONSOLE_SEND;
|
|
}
|
|
|
|
#define N 200
|
|
#define CHUNK 4
|
|
#define ARR_LEN (10 * N / 3 + 1)
|
|
|
|
static int arr[ARR_LEN];
|
|
|
|
void print_digit(int d)
|
|
{
|
|
static int cnt = 0;
|
|
|
|
p("%d", d);
|
|
cnt++;
|
|
|
|
if (cnt == CHUNK) {
|
|
p("\n");
|
|
cnt = 0;
|
|
}
|
|
}
|
|
|
|
/* See: https://en.wikipedia.org/wiki/Spigot_algorithm */
|
|
|
|
int main()
|
|
{
|
|
p("\nComputation of %d first digits of PI\n", N);
|
|
|
|
for (int i = 0; i < ARR_LEN; i++)
|
|
arr[i] = 2;
|
|
|
|
int nines = 0;
|
|
int predigit = 0;
|
|
|
|
for (int j = 1; j < N + 1; j++) {
|
|
int q = 0;
|
|
|
|
for (int i = ARR_LEN; i > 0; i--) {
|
|
int x = 10 * arr[i - 1] + q * i;
|
|
arr[i - 1] = x % (2 * i - 1);
|
|
q = x / (2 * i - 1);
|
|
}
|
|
|
|
arr[0] = q % 10;
|
|
q = q / 10;
|
|
|
|
if (9 == q)
|
|
nines++;
|
|
else if (10 == q) {
|
|
print_digit(predigit + 1);
|
|
|
|
for (int k = 0; k < nines; k++)
|
|
print_digit(0);
|
|
|
|
predigit = 0;
|
|
nines = 0;
|
|
}
|
|
else {
|
|
print_digit(predigit);
|
|
predigit = q;
|
|
|
|
if (0 != nines) {
|
|
for (int k = 0; k < nines; k++)
|
|
print_digit(9);
|
|
|
|
nines = 0;
|
|
}
|
|
}
|
|
}
|
|
p("%d", predigit);
|
|
|
|
p("\nDONE\n");
|
|
|
|
/* Stop simulation */
|
|
IO_REG_CTRL = IO_REG_CTRL_STOP;
|
|
|
|
for (;;) {
|
|
};
|
|
}
|