From e0e08a12d4de86b558674fb9f90ad0b0204c26f0 Mon Sep 17 00:00:00 2001
From: Benji Dial <Benji3.141@gmail.com>
Date: Thu, 26 Dec 2019 15:50:21 -0500
Subject: working memory manager

---
 src/kernel/mem.c | 29 +++++++++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

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

diff --git a/src/kernel/mem.c b/src/kernel/mem.c
index 636c23e..99586d9 100644
--- a/src/kernel/mem.c
+++ b/src/kernel/mem.c
@@ -19,6 +19,9 @@ OF THIS SOFTWARE.
 
 #include "mem.h"
 
+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))
@@ -33,8 +36,28 @@ void *allocate_block(uint32_t size, uint16_t proc_n) {
   uint32_t remaining = i->length - size;
   i->whose = proc_n;
   i->length = size;
-  struct mmap_entry *new;
-  //TODO: ALLOCATE NEW
+
+  uint32_t byte = last_byte;
+  uint32_t mask = last_mask;
+  do {
+    if (!(mask <<= 1)) {
+      mask = 0x00000001;
+      if (++byte == MMAP_SIZE)
+        byte = 0;
+    }
+    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;
@@ -57,6 +80,7 @@ void deallocate_block(void *start) {
       if (!find_after->whose) {
         find->length += find_after->length;
         find->next = find_after->next;
+        unmark_entry(find_after);
       }
       break;
     }
@@ -66,6 +90,7 @@ void deallocate_block(void *start) {
       if (!find_before->whose) {
         find_before->length += find->length;
         find_before->next = find->next;
+        unmark_entry(find);
       }
       break;
     }
-- 
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