From c3892a2fa787bb7bcf4f6aeebfcf85bdc94ce1e8 Mon Sep 17 00:00:00 2001
From: Yorick Barbanneau <ephase@xieme-art.org>
Date: Fri, 19 Nov 2021 16:52:57 +0100
Subject: [PATCH] TD2 II.4 Various fixes on stack allocation

---
 code/test/threadcreate.c    |  2 +-
 code/userprog/addrspace.cc  | 15 ++++++++-------
 code/userprog/addrspace.h   |  2 +-
 code/userprog/userthread.cc |  5 +++--
 4 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/code/test/threadcreate.c b/code/test/threadcreate.c
index 7e57fe8..d19848e 100644
--- a/code/test/threadcreate.c
+++ b/code/test/threadcreate.c
@@ -14,7 +14,7 @@ void f(int c) {
 
 int main(){
     int i;
-    for (i=65; i < 91; i++){
+    for (i=65; i < 68; i++){
         ThreadCreate(f, i);
     }
     // PutString("end of main()\n");
diff --git a/code/userprog/addrspace.cc b/code/userprog/addrspace.cc
index fa9784e..fd155a4 100644
--- a/code/userprog/addrspace.cc
+++ b/code/userprog/addrspace.cc
@@ -132,7 +132,7 @@ AddrSpace::AddrSpace (OpenFile * executable)
     pageTable[0].valid = FALSE;			// Catch NULL dereference
 
     #ifdef CHANGED
-    int bitmapSize =( UserStacksAreaSize / UserStackSize)-1;
+    int bitmapSize =( UserStacksAreaSize / UserStackSize);
     DEBUG('x', "Initialise thread counter\n");
     threads = 1;
     
@@ -140,7 +140,7 @@ AddrSpace::AddrSpace (OpenFile * executable)
     semThreadsCounter = new Semaphore("AddrSpace_thread_counter", 1);
     semAllocateUserStack = new Semaphore("Stack Avaiable", 1);
 
-    DEBUG('x', "Initialize memory map size:%d", bitmapSize);
+    DEBUG('x', "Initialize memory map size:%d\n", bitmapSize);
     memoryMap = new BitMap(bitmapSize);
     memoryMap->Mark(0);
     #endif //CHANGED
@@ -329,22 +329,23 @@ AddrSpace::AllocateUserStack()
     semAllocateUserStack->P();
     bit = memoryMap->Find();
     semAllocateUserStack->V();
+
     if ( bit == - 1 ) {
         DEBUG('x', "No slot avaible on User Stack\n");
         return -1;
     }
-    int addr = memory - UserStackSize * bit;
-    DEBUG('x', "Allocate User Stack bit %d, addr:%x\n", bit, addr);
+    int addr = memory - (UserStackSize * bit);
+    DEBUG('x', "Allocate User Stack bit %d, addr:0x%x\n", bit, (int)addr);
     return addr;
 }
 
 void
 AddrSpace::DeAllocateUserStack(int addr){
     int memory =  numPages * PageSize;
-    int bit = (memory - addr) / UserStackSize;
-    DEBUG('x', "Deallocate User Stack bit %d, addr:%x\n", bit, addr);
+    int bit = ((memory - addr) / UserStackSize);
+    DEBUG('x', "Deallocate User Stack bit %d, addr:0x%x\n", bit, addr);
     semAllocateUserStack->P();
     memoryMap->Clear(bit);
-    semAllocateUserStack->P();
+    semAllocateUserStack->V();
 }
 #endif
diff --git a/code/userprog/addrspace.h b/code/userprog/addrspace.h
index 617b37a..ea68b64 100644
--- a/code/userprog/addrspace.h
+++ b/code/userprog/addrspace.h
@@ -26,7 +26,7 @@ class Semaphore;
 #define UserStackSize           256
 #endif //CHANGED
 
-#define UserStacksAreaSize		1024	// increase this as necessary!
+#define UserStacksAreaSize		4096	// increase this as necessary!
 
 class AddrSpace:public dontcopythis
 {
diff --git a/code/userprog/userthread.cc b/code/userprog/userthread.cc
index f2eb94e..3904fac 100644
--- a/code/userprog/userthread.cc
+++ b/code/userprog/userthread.cc
@@ -52,11 +52,12 @@ int do_ThreadCreate(int f, int arg){
     args->arg = arg;
     
     // Check if we can allocate Stack for our son
-    int stackAddr = currentThread->space->AllocateUserStack();
-    if ( stackAddr == -1 ) {
+    args->stackAddr = currentThread->space->AllocateUserStack();
+    if ( args->stackAddr == -1 ) {
         fprintf(stderr, "Segmentation Fault - no space avaible on stack\n");
         Exit(1);
     }
+    DEBUG('x',"Father found stack address: 0x%x\n", args->stackAddr);
     // create a new Thread and start it
     Thread * newThread = new Thread("new thread");