1 files changed, 145 insertions, 0 deletions
diff --git a/src/mm.c b/src/mm.c
new file mode 100644
index 0000000..e7fa067
--- /dev/null
+++ b/src/mm.c
@@ -0,0 +1,145 @@
+/*
+ * Open Hack'Ware BIOS memory management.
+ * 
+ * Copyright (c) 2004-2005 Jocelyn Mayer
+ * 
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License V2
+ *   as published by the Free Software Foundation
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <stdlib.h>
+#include "bios.h"
+
+#if 0
+static uint8_t *page_bitmap;
+static uint32_t memory_size;
+
+static void mark_page_in_use (uint32_t page_nb)
+{
+    uint32_t offset, bit;
+
+    offset = page_nb >> 3;
+    bit = page_nb & 7;
+    page_bitmap[offset] |= 1 << bit;
+}
+
+static void mark_page_free (uint32_t page_nb)
+{
+    uint32_t offset, bit;
+
+    offset = page_nb >> 3;
+    bit = page_nb & 7;
+    page_bitmap[offset] &= ~(1 << bit);
+}
+
+static int is_page_in_use (uint32_t page_nb)
+{
+    uint32_t offset, bit;
+
+    offset = page_nb >> 3;
+    bit = page_nb & 7;
+    
+    return (page_bitmap[offset] & (~(1 << bit))) != 0;
+}
+
+void mm_init (uint32_t memsize)
+{
+    uint32_t page_start, page_ram_start, page, ram_start;
+    uint32_t nb_pages, bitmap_size;
+    
+    /* Init bitmap */
+    ram_start = (uint32_t)(&_ram_start);
+    ram_start = (ram_start + (1 << 12) - 1) & ~((1 << 12) - 1);
+    page_bitmap = (void *)ram_start;
+    nb_pages = (memsize + (1 << 12) - 1) >> 12;
+    bitmap_size = (nb_pages + 7) >> 3;
+    /* First mark all pages as free */
+    memset(page_bitmap, 0, bitmap_size);
+    /* Mark all pages used by the BIOS as used (code + data + bitmap) */
+    page_start = (uint32_t)(0x05800000) >> 12; /* TO FIX */
+    ram_start += bitmap_size;
+    ram_start = (ram_start + (1 << 12) - 1) & ~((1 << 12) - 1);
+    page_ram_start = ram_start >> 12;
+    for (page = page_start; page < page_ram_start; page++)
+        mark_page_in_use(page);
+    memory_size = memsize;
+}
+
+void *page_get (int nb_pages)
+{
+    uint32_t page_start, page_end, page;
+    int nb;
+
+    page_start = (uint32_t)(0x05800000) >> 12; /* TO FIX */
+    page_end = memory_size >> 12;
+    for (page = page_start; page < page_end; ) {
+        /* Skip all full "blocs" */
+        for (; page < page_end; page += 8) {
+            if (page_bitmap[page >> 3] != 0xFF)
+                break;
+        }
+        for (nb = 0; page < page_end; page++) {
+            if (!is_page_in_use(page)) {
+                nb++;
+                if (nb == nb_pages) {
+                    /* Found ! */
+                    for (; nb >= 0; nb--, page--)
+                        mark_page_in_use(page);
+
+                    return (void *)(page << 12);
+                }
+            }
+        }
+    }
+
+    return NULL;
+}
+
+void page_put (void *addr, int nb_pages)
+{
+    uint32_t page_start, page_end, page;
+
+    page_start = (uint32_t)addr >> 12;
+    page_end = page_start + nb_pages;
+    for (page = page_start; page < page_end; page++) {
+        if (!is_page_in_use(page))
+            printf("ERROR: page %u has already been freed !\n", page);
+        mark_page_free(page);
+    }
+}
+#else
+static uint8_t *page_alloc;
+
+void mm_init (unused uint32_t memsize)
+{
+    uint32_t ram_start;
+    ram_start = (uint32_t)(&_ram_start);
+    ram_start = (ram_start + (1 << 12) - 1) & ~((1 << 12) - 1);
+    page_alloc = (void *)ram_start;
+}
+
+void *page_get (unused int nb_pages)
+{
+    void *ret;
+
+    ret = page_alloc;
+    page_alloc += nb_pages << 12;
+    memset(ret, 0, nb_pages << 12);
+
+    return ret;
+}
+
+void page_put (unused void *addr, unused int nb_pages)
+{
+}
+#endif