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PMM -- simplification of code

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This commit is contained in:
Thomas Lovén 2018-03-20 10:20:27 +01:00
parent 9bc1abceff
commit e86857dca4
1 changed files with 12 additions and 9 deletions
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21
src/kernel/memory/pmm.c
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@ -1,25 +1,28 @@
#include <memory.h>
uint64_t first = 0;
// Virtual addres of next free page
uint64_t next = 0;
void pmm_free(uint64_t page)
{
page = (uint64_t)P2V(page);
*(uint64_t *)page = first;
first = page;
// Write previous free pointer to freed page
*(uint64_t *)P2V(page) = next;
// And update free pointer
next = (uint64_t)P2V(page);
}
uint64_t pmm_alloc()
{
uint64_t page = first;
first = page?*(uint64_t *)page:0;
page = (uint64_t)(page?V2P(page):0);
return page;
if(!next) return 0;
uint64_t page = next;
// Read new free pointer from allocated page
next = *(uint64_t *)page;
return (uint64_t)V2P(page);
}
uint64_t pmm_calloc()
{
uint64_t page = pmm_alloc();
memset(P2V(page), 0, 0x1000);
memset(P2V(page), 0, PAGE_SIZE);
return page;
}