2020-11-30 06:40:33 -05:00
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#include "config.h"
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2020-11-27 05:42:13 -05:00
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#include <kernaux/pfa.h>
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2020-11-30 17:54:09 -05:00
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#include <kernaux/stdlib.h>
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void KernAux_PFA_initialize(struct KernAux_PFA *const pfa)
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{
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kernaux_memset(pfa->pages, KERNAUX_FALSE, sizeof(pfa->pages));
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}
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void KernAux_PFA_mark_available(
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struct KernAux_PFA *const pfa,
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unsigned int start,
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unsigned int end
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) {
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if (start >= end) {
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return;
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}
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const unsigned int start_rem = start % KERNAUX_PFA_PAGE_SIZE;
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const unsigned int end_rem = (end + 1) % KERNAUX_PFA_PAGE_SIZE;
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if (start_rem != 0) {
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start = start - start_rem + KERNAUX_PFA_PAGE_SIZE;
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}
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if (end_rem != 0) {
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end = end - end_rem;
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}
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const unsigned int start_index = start / KERNAUX_PFA_PAGE_SIZE;
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const unsigned int end_index = end / KERNAUX_PFA_PAGE_SIZE;
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for (unsigned int index = start_index; index <= end_index; ++index) {
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pfa->pages[index] = KERNAUX_TRUE;
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}
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}
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2020-11-30 18:38:55 -05:00
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unsigned int KernAux_PFA_alloc_page(struct KernAux_PFA *pfa)
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{
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// We start from 1 because 0 indicates failure.
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// It is not very usefull to alloc page at address 0;
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//
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for (unsigned int index = 1; index < KERNAUX_PFA_PAGES_COUNT_MAX; ++index) {
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if (pfa->pages[index]) {
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pfa->pages[index] = KERNAUX_FALSE;
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return index * KERNAUX_PFA_PAGE_SIZE;
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}
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}
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return 0;
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}
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void KernAux_PFA_free_page(struct KernAux_PFA *pfa, unsigned int page_addr)
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{
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if (page_addr % KERNAUX_PFA_PAGE_SIZE != 0) {
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return;
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}
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pfa->pages[page_addr / KERNAUX_PFA_PAGE_SIZE] = KERNAUX_TRUE;
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}
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