#include <assert.h>
#include <stdint.h>
#include <stdio.h>

#define PPN_MASK    (UINT64_MAX >> 20)

#define PPN_TO_PA(PPN) ((PPN & PPN_MASK) << 12)
#define PA_TO_PPN(PA)  (PA >> 12)

#define ALIGN_UP(n, align)   (((n) + (align) - 1) & ~((align) - 1))
#define ALIGN_DOWN(n, align) ((n) & ~((align) - 1))

#define IS_ALIGNED(x, align)     (((uintptr_t)(x) & ((uintptr_t)(align) - 1)) == 0)
#define IS_ALIGNED_ANY(x, align) (((uintptr_t)(x) % (uintptr_t)(align)) == 0)

#define IS_POWER_OF_TWO(x) (((x) != 0) && (((x) & ((x) - 1)) == 0))
#define IS_ALIGNED_POW2(x, align)                                                                                      \
    (assert(IS_POWER_OF_TWO((uintptr_t)(align))), (((uintptr_t)(x) & ((uintptr_t)(align) - 1)) == 0))

#define VM_MODE_SV39 (2 << 64)

#define PTE_V (1 << 0)
#define PTE_R (1 << 1)
#define PTE_W (1 << 2)
#define PTE_X (1 << 3)
/* And so on... */

#define IS_LEAF(PTE) ((PTE & (PTE_R | PTE_W | PTE_X)) != 0)

#define PTE_PPN(PTE, LEVEL) (((PTE) >> (10 + ((LEVEL) * 9)) & 0x1FF))

int main(void) {
    assert(IS_ALIGNED(0, 1));
    assert(IS_ALIGNED(8, 8));
    assert(IS_ALIGNED(12, 4));
    assert(!IS_ALIGNED(66, 16));
    assert(!IS_ALIGNED(234, 4096));
    assert(!IS_ALIGNED(4099, 4096));

    assert(PPN_MASK == 0b11111111111111111111111111111111111111111111);
    assert(PPN_MASK == 17592186044415);
    assert(PPN_MASK == 0xFFFFFFFFFFF);

    printf("%lu", PPN_TO_PA(0xAAAAAA));
    assert(IS_ALIGNED(PPN_TO_PA(0xAAAAAAAAAAAA), 4096));

    uint64_t pte = 0b11111111110000000001111111110000000001111111111;

    assert(pte & PTE_V);
    assert(pte & PTE_R);
    assert(pte & PTE_W);
    assert(pte & PTE_X);

    assert(IS_LEAF(pte));

    assert(PTE_PPN(pte, 0) == 0);
    assert(PTE_PPN(pte, 1) == 0b111111111);
    assert(PTE_PPN(pte, 2) == 0);
    pte <<= 9;
    assert(PTE_PPN(pte, 0) == 0b111111111);
    assert(PTE_PPN(pte, 1) == 0);
    assert(PTE_PPN(pte, 2) == 0b111111111);

    assert(!IS_LEAF(pte)); // Rightmost bits are now shifted out

}