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-rw-r--r--arch/i386/include/kernel/alloc.h13
-rw-r--r--arch/i386/kernel/alloc.c43
2 files changed, 56 insertions, 0 deletions
diff --git a/arch/i386/include/kernel/alloc.h b/arch/i386/include/kernel/alloc.h
new file mode 100644
index 0000000..986bcc5
--- /dev/null
+++ b/arch/i386/include/kernel/alloc.h
@@ -0,0 +1,13 @@
+#ifndef I386_ALLOC_H
+#define I386_ALLOC_H
+
+#include <kernel/multiboot.h>
+#include <stdint.h>
+#include <stddef.h>
+
+int alloc_init(struct mboot_info *info);
+void mark_bitmap(uint32_t paddr, int present);
+uint32_t pfa_alloc_frame(void);
+void pfa_free(uint32_t paddr, int num_frames);
+
+#endif
diff --git a/arch/i386/kernel/alloc.c b/arch/i386/kernel/alloc.c
new file mode 100644
index 0000000..d2ddf79
--- /dev/null
+++ b/arch/i386/kernel/alloc.c
@@ -0,0 +1,43 @@
+#include <kernel/alloc.h>
+#include <kernel/paging.h>
+#include <kernel/io.h>
+#include <stdint.h>
+
+extern uint32_t _bitmap_start;
+static uint32_t *bm_start = &_bitmap_start;
+
+static struct mboot_info *info;
+
+int alloc_init(struct mboot_info *info) {
+ struct mboot_mmap_entry *mme;
+ for (uint32_t i = 0; i < info->mmap_length; i += sizeof(struct mboot_mmap_entry)) {
+ mme = (struct mboot_mmap_entry*)(info->mmap_addr + i);
+ if (mme->type != MBOOT_MEM_AVAILABLE)
+ mark_bitmap(mme->addr_low, 1);
+ }
+ return 0;
+}
+
+void mark_bitmap(uint32_t paddr, int present) {
+ uint32_t index = (paddr & 0xFFFFF000) / 4096 / 32;
+ uint32_t bit = (paddr & 0xFFFFF000) / 4096 % 32;
+ bm_start[index] |= (present << bit);
+}
+
+uint32_t pfa_alloc_frame(void) {
+ for (uint32_t i = 0; i < 4096; i++) {
+ uint32_t index = i / 32;
+ uint32_t bit = i % 32;
+ if ((bm_start[index] & (1 << bit)) == 0) {
+ mark_bitmap(i*4096, 1);
+ return i * 4096;
+ }
+ }
+ __asm__ volatile("hlt");
+ return 0xFFFFFFFF;
+}
+
+void pfa_free(uint32_t paddr, int num_frames) {
+ for (int i = 0; i < num_frames; i++)
+ mark_bitmap(paddr + (i*4096), 0);
+}