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// See LICENSE for license details.
#include "cfg.h"
#include "mmu.h"
#include "decode.h"
mem_cfg_t::mem_cfg_t(reg_t base, reg_t size) : base(base), size(size)
{
assert(mem_cfg_t::check_if_supported(base, size));
}
bool mem_cfg_t::check_if_supported(reg_t base, reg_t size)
{
// The truth of these conditions should be ensured by whatever is creating
// the regions in the first place, but we have them here to make sure that
// we can't end up describing memory regions that don't make sense. They
// ask that the page size is a multiple of the minimum page size, that the
// page is aligned to the minimum page size, that the page is non-empty and
// that the top address is still representable in a reg_t.
//
// Note: (base + size == 0) part of the assertion is to handle cases like
// { base = 0xffff_ffff_ffff_f000, size: 0x1000 }
return (size % PGSIZE == 0) &&
(base % PGSIZE == 0) &&
(size > 0) &&
((base + size > base) || (base + size == 0));
}
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