added some physical memory management

5 files changed, 178 insertions, 92 deletions

diff --git a/Makefile b/Makefile
index 98f0f66..642f143 100644
--- a/Makefile
+++ b/Makefile
@@ -32,6 +32,9 @@ kernel_entry.o: boot/kernel_entry.asm
 kernel.o: kernel/kernel.c kernel/console.h
 	gcc -ffreestanding -m32 -o $@ -c $< -fno-asynchronous-unwind-tables -O0
 
+mem.o: kernel/mem.c 
+	gcc -ffreestanding -m32 -o $@ -c $< -fno-asynchronous-unwind-tables -O0
+
 console.o: kernel/console.c kernel/console.h
 	gcc -ffreestanding -m32 -o $@ -c $< -fno-asynchronous-unwind-tables -O0
 
@@ -47,7 +50,7 @@ timer.o: kernel/timer.c
 shell.o: kernel/shell.c
 	gcc -ffreestanding -m32 -o $@ -c $< -fno-asynchronous-unwind-tables -O0
 
-kernel.bin: kernel_entry.o kernel.o console.o interrupts.o keyboard.o timer.o shell.o
+kernel.bin: kernel_entry.o kernel.o console.o interrupts.o keyboard.o timer.o shell.o mem.o
 	ld -o $@ -Ttext 0x1000 --oformat binary -melf_i386 $^ -O0
 
 
diff --git a/kernel/console.c b/kernel/console.c
index 27b21e5..77b5fc1 100644
--- a/kernel/console.c
+++ b/kernel/console.c
@@ -104,6 +104,7 @@ void scr_put_char(char ch,char col)
     if(posx>=SCR_WIDTH)scr_nextline();
 }
 
+
 void scr_put_hex(uint16_t val)
 {
 
@@ -121,6 +122,15 @@ void scr_put_hex(uint16_t val)
 }
 
 
+void scr_put_hex32(uint32_t val)
+{
+    scr_put_string("[");
+    scr_put_hex(val>>16);   
+    scr_put_string(",");
+    scr_put_hex(val&0xffff);
+    scr_put_string("]");
+}
+
 void scr_put_string(char *str)
 {
     while(*str!=0)
diff --git a/kernel/interrupts.c b/kernel/interrupts.c
index 49a29a3..a07cfef 100644
--- a/kernel/interrupts.c
+++ b/kernel/interrupts.c
@@ -60,7 +60,7 @@ void int_def_handler()
 void int_install_ir(int irq, uint16_t flags, uint16_t sel, void *addr)
 {
 
-    uint64_t base=(uint64_t)&(*addr);	// TODO!
+   uint64_t base=(uint64_t)&(*addr);	// TODO!
 
     idt[irq].addrLo = base & 0xffff;
     idt[irq].addrHi = (base >> 16) & 0xffff;
diff --git a/kernel/kernel.c b/kernel/kernel.c
index 7c5f982..0e6b32e 100644
--- a/kernel/kernel.c
+++ b/kernel/kernel.c
@@ -36,96 +36,8 @@ void kernel_main()
     timer_init();
     scr_put_string_nl("Configured PIT Channel 0 : Mode 2 : 1/25 s.");
 
-    /*
-    //probe memory
-    scr_put_string_nl("Probing core memory...");
-    char *prober=0xf000;
-
-    for(;prober<0xfffffff;prober+=0xf00)
-    {
-	*prober='x';
-	if(*prober!='x')break;
-    
-    }
-
-    
-    //0xA5000
-    scr_put_hex((uint32_t)prober>>16);
-    scr_put_hex((uint32_t)prober&0xffff);
-    scr_put_string_nl(" finished!");
-    //
-
-    */
-
-    uint16_t *memmap=0x7c00+0x120;
-    uint32_t avail_mem=0;
-
-    //print memory map:
-    
-    while(1)
-    {
-	if(memmap[8]==0)break;
-	if(memmap[8]==1)
-	{
-	    avail_mem+=memmap[4]+(memmap[5]<<16); 
-	}
-	//bytes: 8 8 4 4// 
-	//scr_put_hex(memmap[3]);
-	//scr_put_string(" ");
-	//scr_put_hex(memmap[2]);
-	//scr_put_string(" ");
-	scr_put_hex(memmap[1]);
-	scr_put_string(" ");
-	scr_put_hex(memmap[0]);
-	scr_put_string(" ");
-//	scr_put_hex(memmap[4]);
-//	scr_put_string(" ");
-//	scr_put_hex(memmap[5]);
-//	scr_put_string(" ");
-//	scr_put_hex(memmap[6]);
-//	scr_put_string(" ");
-//	scr_put_hex(memmap[7]);
-	
-
-	scr_put_string(" - ");
-//	scr_put_hex(memmap[8]);
-//	scr_put_string(" ");
-//	scr_put_hex(memmap[9]);
-//	scr_put_string(" ");
-//	scr_put_hex(memmap[10]);
-//	scr_put_string(" ");
-//	scr_put_hex(memmap[11]);
-//	scr_put_string(" ");
-	//scr_put_hex(memmap[7]);
-	//scr_put_string(" ");
-	//scr_put_hex(memmap[6]);
-	//scr_put_string(" ");
-	scr_put_hex(memmap[5]);
-	scr_put_string(" ");
-	scr_put_hex(memmap[4]);
-
-	scr_put_string(" : ");
-	scr_put_hex(memmap[8]);
-//	scr_put_string(" ");
-//	scr_put_hex(memmap[9]);
-	
-
-	scr_put_string_nl("");
-
-	memmap+=12;
-    }
-
-    
-    scr_put_string("Total Available Mem: ");
-    scr_put_hex(avail_mem>>16);
-    scr_put_string(" ");
-    scr_put_hex(avail_mem&0xffff);
-    scr_put_string_nl(" byte");
-    scr_put_string_nl("");
-
-
-
-
+    // we know that here the bootloader placed the mamory map!
+    mem_init(0x7c00+0x120);
 
     // init and interrupt decriptor table 
     int_init(0x08);
diff --git a/kernel/mem.c b/kernel/mem.c
new file mode 100644
index 0000000..1bb4109
--- /dev/null
+++ b/kernel/mem.c
@@ -0,0 +1,161 @@
+#include "kernel.h"
+
+//! 8 blocks per byte
+#define PMMNGR_BLOCKS_PER_BYTE 8
+ 
+//! block size (4k)
+#define PMMNGR_BLOCK_SIZE	4096
+ 
+//! block alignment
+#define PMMNGR_BLOCK_ALIGN	PMMNGR_BLOCK_SIZE
+
+// memory map bit array. Each bit represents a memory block
+static uint32_t	_mmngr_memory_map[129*1024];
+static uint32_t mem_free_blocks;
+
+// bit funcs!
+
+void mmap_set(int bit) 
+{
+      _mmngr_memory_map[bit / 32] |= (1 << (bit % 32));
+}
+
+void mmap_unset(int bit)
+{
+      _mmngr_memory_map[bit / 32] &= ~ (1 << (bit % 32));
+}
+
+int  mmap_test(int bit)
+{
+     return _mmngr_memory_map[bit / 32] &  (1 << (bit % 32));
+}
+
+///
+
+int mmap_first_free () {
+ 
+    //! find the first free bit
+    uint32_t i;
+    int j;
+
+
+    for (i=0; i< 128 ; i++)
+	if (_mmngr_memory_map[i] != 0xffffffff)
+	    for (j=0; j<32; j++) {		//! test each bit in the dword
+ 
+		int bit = 1 << j;
+		if (! (_mmngr_memory_map[i] & bit) )
+		    return i*4*8+j;
+	    }
+ 
+    return -1;
+}
+
+void pmmngr_init () {
+ 
+    //! By default, all of memory is in use
+    //    memset (_mmngr_memory_map, 0xf, 128 );
+    int i;
+    for(i=0;i++;i<128*1024)
+    {
+	_mmngr_memory_map[i]=0xffffffff;
+    }
+}
+
+void pmmngr_init_region (uint32_t  base, uint32_t size)
+{
+
+ 
+    uint32_t align = base / PMMNGR_BLOCK_SIZE;
+    uint32_t blocks = size / PMMNGR_BLOCK_SIZE;
+
+    for (; blocks>0; blocks--) 
+    {
+	// hack to lock first ~4MB of memory
+	if(align<1000)
+	{
+	    align++;
+	    continue;
+	}
+
+
+	mmap_unset (align++);
+	mem_free_blocks++;
+	//_mmngr_used_blocks--;
+    }
+
+    //mmap_set (0);	//first block is always set. This insures allocs cant be 0
+}
+
+void mem_test(int start, int end, int steps)
+{
+    int *p=start;
+    for(;p<end;p+=steps)
+    {
+	scr_put_string("testing memory at ");
+	scr_put_hex32(p);
+
+	//
+	*p=p;
+	volatile x=*p;
+	if(x==p) scr_put_string(" OK");
+	//
+
+	scr_put_string_nl("");
+    }
+}
+
+void mem_init(uint16_t *memmap)
+{
+    mem_free_blocks=0;
+
+    // count available memory
+    uint32_t avail_mem=0;
+
+    //print memory map;
+    while(1)
+    {
+	if(memmap[8]==0)break;
+
+	scr_put_hex(memmap[8]);
+	scr_put_string(" : ");
+
+
+	scr_put_hex(memmap[1]);
+	scr_put_string(" ");
+	scr_put_hex(memmap[0]);
+	scr_put_string(" ");
+
+	scr_put_string(" - ");
+	scr_put_hex(memmap[5]);
+	scr_put_string(" ");
+	scr_put_hex(memmap[4]);
+
+	scr_put_string_nl("");
+
+	if(memmap[8]==1)
+	{
+	    avail_mem+=memmap[4]+(memmap[5]<<16); 
+	    pmmngr_init_region(memmap[0]+(memmap[1]<<16),memmap[4]+((memmap[5])<<16));
+	}
+
+	memmap+=12;
+    }
+
+    scr_put_string("Total Available Mem: ");
+    scr_put_hex(avail_mem>>16);
+    scr_put_string(" ");
+    scr_put_hex(avail_mem&0xffff);
+    scr_put_string_nl(" byte");
+
+    scr_put_string("Total of free (4KB) blocks: ");
+    scr_put_hex(mem_free_blocks>>16);
+    scr_put_hex(mem_free_blocks&0xffff);
+    scr_put_string_nl("");
+
+    //crossing 512MB boundary! 
+    // (do not do this in real, coz it probably is reserved)
+    //mem_test(0x1fee1000,0x2000f000,0x800);
+
+}
+