working memory manager

7 files changed, 62 insertions, 51 deletions

diff --git a/src/kernel/files.h b/src/kernel/files.h
index 38e59f1..f7665dc 100644
--- a/src/kernel/files.h
+++ b/src/kernel/files.h
@@ -29,7 +29,7 @@ struct file_info {
   uint32_t position;
 };
 
-struct file_info *file_table;
+struct file_info file_table[65536];
 uint16_t open_file(uint8_t *name);
 void close_file(uint16_t handle);
 void read_file(uint16_t handle, uint32_t length, void *buffer);
diff --git a/src/kernel/main.c b/src/kernel/main.c
index ab8eb91..97226bd 100644
--- a/src/kernel/main.c
+++ b/src/kernel/main.c
@@ -60,6 +60,7 @@ struct boot_device_tag {
 
 enum mem_type {
   AVAILABLE = 1,
+  HARDWARET = 2,
   ACPI      = 3,
   PRESERVE  = 4,
   DEFECTIVE = 5
@@ -78,7 +79,8 @@ bool have_mmap = false;
 enum error_codes {
   NO_BOOT_DEVICE = 0x00000000,
   NO_MMAP        = 0x00000001,
-  INSUFF_MEMORY  = 0x00000002
+  INSUFF_MEMORY  = 0x00000002,
+  MMAP_TOO_SMALL = 0x00000003
 };
 
 struct tag_start *tag_pointer;
@@ -128,7 +130,9 @@ uint32_t main(void) {
       uint32_t size = *(uint32_t *)(tag_pointer + 1);
       struct mmap_tag_entry *tag = (struct mmap_tag_entry *)(tag_pointer + 2);
       struct mmap_tag_entry *end = (struct mmap_tag_entry *)((uint32_t)tag_pointer + tag_pointer->size);
-      struct mmap_entry *entry = (struct mmap_entry *)tag;
+      struct mmap_entry *entry = mmap_bss;
+      uint32_t bitmask = 0x00000001;
+      uint32_t byte = 0;
       struct mmap_entry **last_next = &mmap_start;
       uint32_t usable = 0;
       put_sz(": memory map\n    Regions:\n");
@@ -147,20 +151,21 @@ uint32_t main(void) {
             entry->whose = FREE;
             usable += entry->length;
             break;
-          case ACPI:
-            put_sz(": ACPI info\n");
-            entry->whose = HARDWARE;
-            break;
+          case HARDWARET:
           case PRESERVE:
             put_sz(": hardware use\n");
             entry->whose = HARDWARE;
             break;
+          case ACPI:
+            put_sz(": ACPI info\n");
+            entry->whose = HARDWARE;
+            break;
           case DEFECTIVE:
             put_sz(": defective\n");
             entry->whose = HARDWARE;
             break;
           default:
-            put_sz(": hardware use (0x");
+            put_sz(": assuming hardware use (0x");
             put_32_hex(tag->type);
             put_sz(")\n");
             entry->whose = HARDWARE;
@@ -168,12 +173,18 @@ uint32_t main(void) {
           }
           *last_next = entry;
           last_next = &entry->next;
+          mmap_bitmap[byte] |= bitmask;
           ++entry;
+          if (!(bitmask <<= 1)) {
+            bitmask = 0x00000001;
+            if (++byte == MMAP_SIZE)
+              return MMAP_TOO_SMALL;
+          }
         }
         tag = (struct mmap_tag_entry *)((uint32_t)tag + size);
       }
 
-      put_sz("    Total usable memory: ");
+      put_sz("    Total usable memory: 0x");
       put_32_hex(usable);
       put_char('\n');
 
@@ -185,6 +196,7 @@ uint32_t main(void) {
             if ((current->base + current->length == against->base) &&
                 (current->whose == against->whose)) {
               current->length += against->length;
+              unmark_entry(against);
               if (against == mmap_start)
                 mmap_start = against->next;
               else {
@@ -211,17 +223,17 @@ uint32_t main(void) {
   if (!have_mmap)
     return NO_MMAP;
 
-  put_sz("Halting.");
-  while (1)
-    ;
-
-  if (!((proc_table = allocate_block(sizeof(struct proc_info) * 65536, KERNEL)) &&
-        (file_table = allocate_block(sizeof(struct file_info) * 65536, KERNEL))))
-    return INSUFF_MEMORY;
+  put_sz("\nReady!\n  Memory map size: 0x");
+  put_32_hex(sizeof(struct mmap_entry) * MMAP_SIZE);
+  put_sz("\n  Process table size: 0x");
+  put_32_hex(sizeof(struct proc_info) * 65536);
+  put_sz("\n  File table size: 0x");
+  put_32_hex(sizeof(struct file_info) * 65536);
+  put_char('\n');
 
-  put_sz("Welcome to Portland version 0.0.9!\n");
+  put_sz("\nWelcome to Portland version 0.0.9!\n");
   while (1)
-    put_sz("|\b/\b-\b\\\b");
+    asm ("hlt");
 }
 
 void wrapped_main(void) {
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;
     }
diff --git a/src/kernel/mem.h b/src/kernel/mem.h
index 106db90..5c0d387 100644
--- a/src/kernel/mem.h
+++ b/src/kernel/mem.h
@@ -35,7 +35,11 @@ struct mmap_entry {
   struct mmap_entry *next;
 };
 
+#define MMAP_SIZE 65536
 struct mmap_entry *mmap_start;
+struct mmap_entry mmap_bss[MMAP_SIZE];
+uint32_t mmap_bitmap[MMAP_SIZE / 32];
+#define unmark_entry(entry) mmap_bitmap[((entry) - mmap_bss) >> 5] ^= 1 << (((entry) - mmap_bss) & 0x0000001f);
 void *allocate_block(uint32_t size, uint16_t proc_n);
 void deallocate_block(void *start);
 
diff --git a/src/kernel/proc.h b/src/kernel/proc.h
index 261ae6b..bbff903 100644
--- a/src/kernel/proc.h
+++ b/src/kernel/proc.h
@@ -27,7 +27,7 @@ struct proc_info {
   void *memory_end;
 };
 
-struct proc_info *proc_table;
+struct proc_info proc_table[65536];
 uint16_t new_proc(uint8_t *file);
 void end_proc(uint16_t id);
 
diff --git a/src/kernel/vga.c b/src/kernel/vga.c
index 78da721..5fd8a46 100644
--- a/src/kernel/vga.c
+++ b/src/kernel/vga.c
@@ -70,30 +70,6 @@ void put_sz(uint8_t *sz) {
     put_char(*(sz++));
 }
 
-void put_16(uint16_t n) {
-  bool s = false;
-  if (n / 10000) {
-    put_char((uint8_t)'0' + n / 10000);
-    s = true;
-  }
-  n %= 10000;
-  if (n / 1000 || s) {
-    put_char((uint8_t)'0' + n / 1000);
-    s = true;
-  }
-  n %= 1000;
-  if (n / 100 || s) {
-    put_char((uint8_t)'0' + n / 100);
-    s = true;
-  }
-  n %= 100;
-  if (n / 10 || s) {
-    put_char((uint8_t)'0' + n / 10);
-    s = true;
-  }
-  put_char((uint8_t)'0' + n % 10);
-}
-
 void put_32_hex(uint32_t n) {
   for (uint8_t i = 0; i < 4; ++i) {
     put_char("0123456789abcdef"[n >> 28]);
diff --git a/src/kernel/vga.h b/src/kernel/vga.h
index 5658437..2504128 100644
--- a/src/kernel/vga.h
+++ b/src/kernel/vga.h
@@ -22,16 +22,10 @@ OF THIS SOFTWARE.
 #ifndef VGA_H
 #define VGA_H
 
-#define put_debug(name, value) \
-  put_sz(name ": 0x"); \
-  put_32_hex(value); \
-  put_char('\n');
-
 #define VGA_BUFFER ((uint8_t *)0x000b8000)
 void clear(void);
 void put_char(uint8_t ch);
 void put_sz(uint8_t *s);
-void put_16(uint16_t n);
 void put_32_hex(uint32_t n);
 void move_cursor(uint8_t col, uint8_t row);
 void set_color(uint8_t c);