From 58b5c8ba417fe99c01d9a48731b887ce434e797e Mon Sep 17 00:00:00 2001
From: Benji Dial <Benji3.141@gmail.com>
Date: Fri, 27 Dec 2019 17:19:51 -0500
Subject: lots of new stuff. new memory manager, some stuff on file plumbing

---
 src/kernel/mem.c | 115 +++++++++++++++++++++++++------------------------------
 1 file changed, 53 insertions(+), 62 deletions(-)

(limited to 'src/kernel/mem.c')

diff --git a/src/kernel/mem.c b/src/kernel/mem.c
index 99586d9..d9322a9 100644
--- a/src/kernel/mem.c
+++ b/src/kernel/mem.c
@@ -23,75 +23,66 @@ uint32_t last_byte = 0;
 uint32_t last_mask = 0x00000001;
 
 void *allocate_block(uint32_t size, uint16_t proc_n) {
-  struct mmap_entry *i = mmap_start;
-  while (i->whose || (i->length < size))
-    if (i->next)
-      i = i->next;
-    else
-      return (void *)0;
-  if (i->length == size) {
-    i->whose = proc_n;
-    return (void *)i->base;
-  }
-  uint32_t remaining = i->length - size;
-  i->whose = proc_n;
-  i->length = size;
-
-  uint32_t byte = last_byte;
-  uint32_t mask = last_mask;
-  do {
-    if (!(mask <<= 1)) {
-      mask = 0x00000001;
-      if (++byte == MMAP_SIZE)
-        byte = 0;
+  for (struct mmap_entry *find = mmap_start; find; find = find->after)
+    if (!find->whose) {
+      if (find->length == size) {
+        find->whose = proc_n;
+        return (void *)find->base;
+      }
+      else if (find->length > size) {
+        uint32_t byte = last_byte;
+        uint32_t mask = last_mask;
+        while (mmap_bitmap[byte] & mask) {
+          if ((byte == last_byte) && (mask == last_mask)) {
+            while (find = find->after)
+              if (find->length == size) {
+                find->whose = proc_n;
+                return (void *)find->base;
+              }
+            return (void *)0;
+          }
+          if (!(mask <<= 1)) {
+            mask = 0x00000001;
+            if (++byte == MMAP_SIZE)
+              byte = 0;
+          }
+        }
+        mmap_bitmap[last_byte = byte] |= last_mask = mask;
+        struct mmap_entry *new = mmap_bss + (byte << 5);
+        while (mask >>= 1)
+          ++new;
+        ((((new->after = find->after)->before = new)->before = find)->after = new)->base = find->base + size;
+        new->length = find->length - size;
+        find->length = size;
+        find->whose = proc_n;
+        new->whose = FREE;
+        return (void *)find->base;
+      }
     }
-    if ((byte == last_byte) && (mask == last_mask))
-      return 0;
-  } while (mmap_bitmap[byte] & mask);
-  last_byte = byte;
-  last_mask = mask;
-  mmap_bitmap[byte] |= mask;
-  uint8_t bit = 0;
-  while (!(mask & 0x00000001)) {
-    ++bit;
-    mask >>= 1;
-  }
-
-  struct mmap_entry *new = mmap_bss + (byte << 5) + bit;
-  new->base = i->base + size;
-  new->length = remaining;
-  new->whose = FREE;
-  new->next = i->next;
-  i->next = new;
-  return (void *)i->base;
+  return (void *)0;
 }
 
 void deallocate_block(void *start) {
   struct mmap_entry *find = mmap_start;
   while (find->base != (uint32_t)start)
-    if (find->next)
-      find = find->next;
+    if (find->after)
+      find = find->after;
     else
       return;
   find->whose = FREE;
-
-  for (struct mmap_entry *find_after = mmap_start; find_after; find_after = find_after->next)
-    if (find_after->base == find->base + find->length) {
-      if (!find_after->whose) {
-        find->length += find_after->length;
-        find->next = find_after->next;
-        unmark_entry(find_after);
-      }
-      break;
-    }
-
-  for (struct mmap_entry *find_before = mmap_start; find_before; find_before = find_before->next)
-    if (find->base == find_before->base + find_before->length) {
-      if (!find_before->whose) {
-        find_before->length += find->length;
-        find_before->next = find->next;
-        unmark_entry(find);
-      }
-      break;
-    }
+  while (find->before && !find->before->whose) {
+    find->before->length += find->length;
+    if (find->before->after = find->after)
+      find->after->before = find->before;
+    unmark_entry(find);
+    find = find->before;
+  }
+  if (!find->before)
+    mmap_start = find;
+  while (find->after && !find->after->whose) {
+    find->length += find->after->length;
+    unmark_entry(find->after);
+    if (find->after = find->after->after)
+      find->after->before = find;
+  }
 }
\ No newline at end of file
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