From e9fcb66d22bc72d4a3926e8bbd18505c079e88d5 Mon Sep 17 00:00:00 2001
From: Kieron Morris <kjm@kieronmorris.me>
Date: Wed, 23 Jun 2021 23:57:06 +0100
Subject: [PATCH] Added klalloc for large allocations.

Added a klalloc and a klfree (not yet implemented) to lmemorymanager.
Added a page_mappable method to vmemorymanager to check if a page is mappable before trying to map, this supports klalloc.
---
 src/lmemorymanager.pas | 41 +++++++++++++++++++++++++++++++++++++++++
 src/vmemorymanager.pas | 17 ++++++++++++++++-
 2 files changed, 57 insertions(+), 1 deletion(-)

diff --git a/src/lmemorymanager.pas b/src/lmemorymanager.pas
index 2cc62539..cc108638 100644
--- a/src/lmemorymanager.pas
+++ b/src/lmemorymanager.pas
@@ -57,6 +57,8 @@ var
 
 procedure init;
 function kalloc(size : uint32) : void;
+function klalloc(size : uint32) : void;
+function klfree(size : uint32); //Todo ??? Profit?
 function kpalloc(address : uint32) : void;
 procedure kfree(area : void);
 
@@ -129,6 +131,45 @@ begin
     //pop_trace;
 end;
 
+function klfree(size : uint32);
+begin
+    //Todo Implement
+    //Nahhhhhhhhhhhh
+end;
+
+function klalloc(size : uint32) : void;
+var
+    Pages : uint16;
+    Address : void;
+    Found : boolean;
+    CurrPage : uint16;
+    i : uint16;
+    Miss : boolean;
+
+begin
+    Pages:= (size div 4000000);
+    Found:= false;
+    CurrPage:= 4;
+    Address:= Void(nil);
+    while not Found do begin
+        inc(CurrPage);
+        if CurrPage > 1024 then break;
+        Miss:= false;
+        for i:=0 to Pages do begin
+            if not page_mappable(CurrPage + i) then Miss:= true;
+            if miss then break;
+        end;
+        if not Miss then begin
+            for i:=0 to Pages do begin
+                new_page(CurrPage + i);
+            end;
+            Address:= Void(CurrPage SHL 22);
+            break;
+        end;
+    end;
+    klalloc:= Address;
+end;
+
 function kalloc(size : uint32) : void;
 var
    Heap_Entries : uint32;
diff --git a/src/vmemorymanager.pas b/src/vmemorymanager.pas
index fbae7ed5..3a1bd7de 100644
--- a/src/vmemorymanager.pas
+++ b/src/vmemorymanager.pas
@@ -53,6 +53,7 @@ var
 
 procedure init;
 function new_page(page_number : uint16) : boolean;
+function page_mappable(page_number : uint16) : boolean;
 function map_page(page_number : uint16; block : uint16) : boolean;
 function map_page_ex(page_number : uint16; block : uint16; PD : PPageDirectory) : boolean;
 function new_page_at_address(address : uint32) : boolean;
@@ -202,7 +203,7 @@ begin
     push_trace('vmemorymanager.new_page');
     new_page:= false;
     if not PageDirectory^[page_number].Present then begin
-        if not PageDirectory^[page_number].Reserved then begin;
+        if not PageDirectory^[page_number].Reserved then begin
             block:= pmemorymanager.new_block(uint32(PageDirectory));
             if block < 2 then begin
                 GPF;
@@ -214,6 +215,20 @@ begin
     pop_trace;
 end;
 
+function page_mappable(page_number : uint16) : boolean;
+var
+    block : uint16;
+
+begin
+    push_trace('vmemorymanager.page_mappable');
+    page_mappable:= false;
+    if not PageDirectory^[page_number].Present then begin
+        if not PageDirectory^[page_number].Reserved then begin
+            page_mappable:= true;
+        end;
+    end;
+end;
+
 function new_page_at_address(address : uint32) : boolean;
 var
     page_number : uint16;