rve/example/example.c

64 lines
1.3 KiB
C

#include "printf.h"
typedef unsigned long long uint64_t;
typedef unsigned long uint32_t;
#define MTIME_BASE 0x0200BFF8
volatile uint32_t* mtime_upper = (uint32_t*)(MTIME_BASE+4);
volatile uint32_t* mtime_lower = (uint32_t*)MTIME_BASE;
#define FRAMEBUFFER_BASE 0x1D385000
uint64_t read_mtime_atomic() {
uint32_t upper1, lower, upper2;
do {
upper1 = *mtime_upper;
lower = *mtime_lower;
upper2 = *mtime_upper;
} while (upper1 != upper2); // Repeat if upper changed during the process
return ((uint64_t)upper1 << 32) | lower;
}
uint32_t timediff_ms(uint64_t start, uint64_t end) {
uint64_t total = end-start;
// Clock rate is currently 1MHz
return (uint32_t)total / 1000;
}
int fib(int n) {
if (n == 0 || n == 1)
return 1;
return fib(n-1) + fib(n-2);
}
void draw() {
for (int k = 0; k < 200; k++) {
for (int i = 0; i< 640; i++) {
for (int j = 0; j < 480; j++) {
uint32_t color = i*(j + k);
uint32_t* addr = (uint32_t*)(FRAMEBUFFER_BASE + ((j*640) + i) *4);
*addr = color;
}
}
}
}
int main() {
uint64_t start = read_mtime_atomic();
draw();
uint64_t end = read_mtime_atomic();
int n = 24;
int res = fib(n);
uint32_t total_msec = timediff_ms(start, end);
printf("fib(%d) = %d\n", n, res);
printf("time: %dms\n", total_msec);
return 0;
}