#include <stdio.h>
#include <stdbool.h>
#define uint64 long long unsigned
#define int64 long long
static void
nearest_powers(uint64 value, uint64 *lower, uint64 *upper)
{
uint64 power = 1UL << 12;
if (lower)
*lower = power;
while (value >= power) {
if (lower)
*lower = power;
power <<= 1;
}
if (upper)
*upper = power;
}
int64 sols[5];
int solCount;
int64 props[5];
static void
find_nearest(uint64 value, int iteration)
{
if (iteration > 4 || (iteration + 1) >= solCount)
return;
uint64 down, up;
int i;
nearest_powers(value, &down, &up);
props[iteration] = down;
if (value - down < 0x100000) {
for (i=0; i<=iteration; i++)
sols[i] = props[i];
solCount = iteration + 1;
return;
}
find_nearest(value - down, iteration + 1);
props[iteration] = -up;
if (up - value < 0x100000) {
for (i=0; i<=iteration; i++)
sols[i] = props[i];
solCount = iteration + 1;
return;
}
find_nearest(up - value, iteration + 1);
}
int
main()
{
uint64 length = 0xbfee0000;
uint64 base = 0;
solCount = 5;
find_nearest(length, 0);
printf("sols ");
int i;
for (i=0; i<solCount; i++) {
printf("0x%Lx ", sols[i]);
}
printf("\n");
bool nextDown = false;
for (i = 0; i < solCount; i++) {
if (sols[i] < 0) {
if (nextDown)
base += sols[i];
printf("%Lx %Lx %s\n", base, -sols[i], nextDown ? "UC" : "WB");
if (!nextDown)
base -= sols[i];
nextDown = !nextDown;
} else {
if (nextDown)
base -= sols[i];
printf("%Lx %Lx %s\n", base, sols[i], nextDown ? "UC" : "WB");
if (!nextDown)
base += sols[i];
}
}
}
