X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fthreads%2Floader.S;h=42f489979dff15704d4cd3efa023c9954f03913b;hb=a23e3e47eb037b5de510b9661635e3df0a5bfdd0;hp=3d440d20d58d2b30c3228c65c278a82cf8d51893;hpb=843e338ee1a66bb6069ddf11d0d2650e6cb5c5f3;p=pintos-anon

diff --git a/src/threads/loader.S b/src/threads/loader.S
index 3d440d2..42f4899 100644
--- a/src/threads/loader.S
+++ b/src/threads/loader.S
@@ -39,7 +39,7 @@
  */
 
 #include "threads/loader.h"
-#include "threads/mmu.h"
+/*#include "threads/mmu.h"*/
 	
 #### Kernel loader.
 
@@ -59,6 +59,8 @@
 
 # Code runs in real mode, which is a 16-bit segment.
 
+.globl start
+start:
 	.code16
 
 # Disable interrupts.
@@ -67,12 +69,16 @@
 	cli
 	cld
 
-# Set up segment registers and stack.
-# Stack grows downward starting from us.
+# Set up data segments and stack.
 
 	subw %ax, %ax
 	movw %ax, %es
 	movw %ax, %ds
+
+# Stack grows downward starting from us.
+# We don't ever use the stack so this is strictly speaking
+# unnecessary.
+
 	movw %ax, %ss
 	movw $0x7c00, %sp
 	
@@ -127,14 +133,16 @@
 	rep stosl
 
 # Set PDEs for 0 and LOADER_PHYS_BASE to point to the page table.
+# See comments near the PG_* macros in paging.h for a description of
+# the values stored here.
 
-	movl $0x11000 | PG_U | PG_W | PG_P, %eax
+	movl $0x11007, %eax
 	movl %eax, %es:0
 	movl %eax, %es:LOADER_PHYS_BASE >> 20
 
 # Initialize page table.
 
-	movl $PG_U | PG_W | PG_P, %eax
+	movl $7, %eax
 	movl $0x400, %ecx
 1:	stosl
 	addl $0x1000, %eax
@@ -247,9 +255,9 @@ read_sector:
 
 # Transfer sector.
 
-	movl $512 / 4, %ecx
+	movl $256, %ecx
 	movl $0x1f0, %edx
-	rep insl
+	rep insw
 
 # Next sector.