fix: last page of the pt is now usable

src/kernel.c

@@ -69,11 +69,25 @@ void kernel_main(multiboot_info_t *mbd, uint32_t magic)
 
 	// PRINT_PTR(alloc_frame());
 	if (false) {
-		void *ptr;
-		while ((ptr = alloc_pages(PAGE_SIZE * 1))) {
-			if (ptr)
-				memset(ptr, ~0, PAGE_SIZE * 1);
+		void *start = alloc_pages(1);
+		int *ptr;
+		uint32_t i;
+		for (i = 1; (ptr = alloc_pages(PAGE_SIZE)); i++) {
+			*ptr = i;
+			if (i == 4096)
+				break;
 		}
+		uint16_t bozo = 0;
+		for (uint32_t j = 1; j < i - 1; j++) {
+			ptr = start + j * PAGE_SIZE;
+			if (*ptr != j) {
+				bozo++;
+				if (bozo == 12)
+					break;
+			}
+			kprintf("j=%d  %p: %d\n", j, ptr, *ptr);
+		}
+
 	} else {
 		while (vmalloc(10))
 			;

src/memory/memory.c

@@ -90,7 +90,8 @@ static void add_frame_node(multiboot_memory_map_t *mmmt)
 	 */
 	if (KERNEL_START <= start_addr && KERNEL_END > start_addr &&
 	    KERNEL_END <= end_addr) {
-		len = len - (KERNEL_END - start_addr);
+		len = ROUND_CEIL(len - (KERNEL_END - start_addr), PAGE_SIZE) -
+		      PAGE_SIZE; // cringe but ROUND_FLOOR is un poquito crampte
 		start_addr = ROUND_CEIL(KERNEL_END, PAGE_SIZE);
 	}
 	end_addr = ROUND_CEIL(start_addr + len, PAGE_SIZE);

src/memory/page.c

@@ -17,7 +17,7 @@ static int16_t find_next_block(size_t nb_pages, uint16_t *pd_index_ptr,
 		}
 		*page_table_ptr =
 		    (uint32_t *)GET_PAGE_ADDR(0, *pd_index_ptr + PT_START);
-		for (uint16_t i = 0; i + nb_pages < PT_SIZE; i++) {
+		for (uint16_t i = 0; i + nb_pages - 1 < PT_SIZE; i++) {
 			uint16_t j;
 			for (j = 0; (*page_table_ptr)[i + j] >> 12 == i + j &&
 			            j < nb_pages;