PRIVATE void estimate_cpu_freq(void)
{
u64_t tsc_delta;
u64_t cpu_freq;
irq_hook_t calib_cpu;
/* set the probe, we use the legacy timer, IRQ 0 */
put_irq_handler(&calib_cpu, CLOCK_IRQ, calib_cpu_handler);
/* just in case we are in an SMP single cpu fallback mode */
BKL_UNLOCK();
/* set the PIC timer to get some time */
intr_enable();
/* loop for some time to get a sample */
while(probe_ticks < PROBE_TICKS) {
intr_enable();
}
intr_disable();
/* just in case we are in an SMP single cpu fallback mode */
BKL_LOCK();
/* remove the probe */
rm_irq_handler(&calib_cpu);
tsc_delta = sub64(tsc1, tsc0);
cpu_freq = mul64(div64u64(tsc_delta, PROBE_TICKS - 1), make64(system_hz, 0));
cpu_set_freq(cpuid, cpu_freq);
cpu_info[cpuid].freq = div64u(cpu_freq, 1000000);
BOOT_VERBOSE(cpu_print_freq(cpuid));
}
static void testdiv0(void)
{
int funcidx;
assert(cmp64u(j, 0) == 0);
/* loop through the 5 different division functions */
for (funcidx = 0; funcidx < 5; funcidx++) {
expect_SIGFPE = 1;
if (setjmp(jmpbuf_SIGFPE) == 0) {
/* divide by zero using various functions */
switch (funcidx) {
case 0: div64(i, j); ERR; break;
case 1: div64u64(i, ex64lo(j)); ERR; break;
case 2: div64u(i, ex64lo(j)); ERR; break;
case 3: rem64(i, j); ERR; break;
case 4: rem64u(i, ex64lo(j)); ERR; break;
default: assert(0); ERR; break;
}
/* if we reach this point there was no signal and an
* error has been recorded
*/
expect_SIGFPE = 0;
} else {
/* a signal has been received and expect_SIGFPE has
* been reset; all is ok now
*/
assert(!expect_SIGFPE);
}
}
}
static void testdiv(void)
{
u64_t q, r;
#if TIMED
struct timeval tvstart, tvend;
printf("i=0x%.8x%.8x; j=0x%.8x%.8x\n",
ex64hi(i), ex64lo(i),
ex64hi(j), ex64lo(j));
fflush(stdout);
if (gettimeofday(&tvstart, NULL) < 0) ERR;
#endif
/* division by zero has a separate test */
if (cmp64u(j, 0) == 0) {
testdiv0();
return;
}
/* perform division, store q in k to make ERR more informative */
q = div64(i, j);
r = rem64(i, j);
k = q;
#if TIMED
if (gettimeofday(&tvend, NULL) < 0) ERR;
tvend.tv_sec -= tvstart.tv_sec;
tvend.tv_usec -= tvstart.tv_usec;
if (tvend.tv_usec < 0) {
tvend.tv_sec -= 1;
tvend.tv_usec += 1000000;
}
printf("q=0x%.8x%.8x; r=0x%.8x%.8x; time=%d.%.6d\n",
ex64hi(q), ex64lo(q),
ex64hi(r), ex64lo(r),
tvend.tv_sec, tvend.tv_usec);
fflush(stdout);
#endif
/* compare to 64/32-bit division if possible */
if (!ex64hi(j)) {
if (cmp64(q, div64u64(i, ex64lo(j))) != 0) ERR;
if (!ex64hi(q)) {
if (cmp64u(q, div64u(i, ex64lo(j))) != 0) ERR;
}
if (cmp64u(r, rem64u(i, ex64lo(j))) != 0) ERR;
/* compare to 32-bit division if possible */
if (!ex64hi(i)) {
if (cmp64u(q, ex64lo(i) / ex64lo(j)) != 0) ERR;
if (cmp64u(r, ex64lo(i) % ex64lo(j)) != 0) ERR;
}
}
/* check results using i = q j + r and r < j */
if (cmp64(i, add64(mul64(q, j), r)) != 0) ERR;
if (cmp64(r, j) >= 0) ERR;
}
