diff --git a/defs.h b/defs.h
index 8231159..0a55759 100644
--- a/defs.h
+++ b/defs.h
@@ -131,7 +131,7 @@ void            release(struct spinlock*);
 void            pushcli(void);
 void            popcli(void);
 void            initsleeplock(struct sleeplock*);
-void            acquire_sleeplock(struct sleeplock*,struct spinlock*);
+void            acquire_sleeplock(struct sleeplock*, struct spinlock*);
 void            release_sleeplock(struct sleeplock*);
 int             acquired_sleeplock(struct sleeplock*);
 
diff --git a/file.c b/file.c
index 2a32c60..df90e07 100644
--- a/file.c
+++ b/file.c
@@ -134,7 +134,7 @@ filewrite(struct file *f, char *addr, int n)
       begin_trans();
       ilock(f->ip);
       if ((r = writei(f->ip, addr + i, f->off, n1)) > 0)
-	f->off += r;
+        f->off += r;
       iunlock(f->ip);
       commit_trans();
 
diff --git a/main.c b/main.c
index 13fed7c..9ebd7c8 100644
--- a/main.c
+++ b/main.c
@@ -107,10 +107,10 @@ startothers(void)
 // Use PTE_PS in page directory entry to enable 4Mbyte pages.
 __attribute__((__aligned__(PGSIZE)))
 pde_t enterpgdir[NPDENTRIES] = {
-	// Map VA's [0, 4MB) to PA's [0, 4MB)
-	[0] = (0) + PTE_P + PTE_W + PTE_PS,
-	// Map VA's [KERNBASE, KERNBASE+4MB) to PA's [0, 4MB)
-	[KERNBASE>>PDXSHIFT] = (0) + PTE_P + PTE_W + PTE_PS,
+  // Map VA's [0, 4MB) to PA's [0, 4MB)
+  [0] = (0) + PTE_P + PTE_W + PTE_PS,
+  // Map VA's [KERNBASE, KERNBASE+4MB) to PA's [0, 4MB)
+  [KERNBASE>>PDXSHIFT] = (0) + PTE_P + PTE_W + PTE_PS,
 };
 
 //PAGEBREAK!
diff --git a/mmu.h b/mmu.h
index e5a4f1e..0da30e7 100644
--- a/mmu.h
+++ b/mmu.h
@@ -25,19 +25,19 @@
 #define FL_ID           0x00200000      // ID flag
 
 // Control Register flags
-#define CR0_PE		0x00000001	// Protection Enable
-#define CR0_MP		0x00000002	// Monitor coProcessor
-#define CR0_EM		0x00000004	// Emulation
-#define CR0_TS		0x00000008	// Task Switched
-#define CR0_ET		0x00000010	// Extension Type
-#define CR0_NE		0x00000020	// Numeric Errror
-#define CR0_WP		0x00010000	// Write Protect
-#define CR0_AM		0x00040000	// Alignment Mask
-#define CR0_NW		0x20000000	// Not Writethrough
-#define CR0_CD		0x40000000	// Cache Disable
-#define CR0_PG		0x80000000	// Paging
+#define CR0_PE          0x00000001      // Protection Enable
+#define CR0_MP          0x00000002      // Monitor coProcessor
+#define CR0_EM          0x00000004      // Emulation
+#define CR0_TS          0x00000008      // Task Switched
+#define CR0_ET          0x00000010      // Extension Type
+#define CR0_NE          0x00000020      // Numeric Errror
+#define CR0_WP          0x00010000      // Write Protect
+#define CR0_AM          0x00040000      // Alignment Mask
+#define CR0_NW          0x20000000      // Not Writethrough
+#define CR0_CD          0x40000000      // Cache Disable
+#define CR0_PG          0x80000000      // Paging
 
-#define CR4_PSE         0x00000010	// Page size extension
+#define CR4_PSE         0x00000010      // Page size extension
 
 #define SEG_KCODE 1  // kernel code
 #define SEG_KDATA 2  // kernel data+stack
@@ -109,39 +109,39 @@ struct segdesc {
 //  \--- PDX(va) --/ \--- PTX(va) --/ 
 
 // page directory index
-#define PDX(va)		(((uint)(va) >> PDXSHIFT) & 0x3FF)
+#define PDX(va)         (((uint)(va) >> PDXSHIFT) & 0x3FF)
 
 // page table index
-#define PTX(va)		(((uint)(va) >> PTXSHIFT) & 0x3FF)
+#define PTX(va)         (((uint)(va) >> PTXSHIFT) & 0x3FF)
 
 // construct virtual address from indexes and offset
-#define PGADDR(d, t, o)	((uint)((d) << PDXSHIFT | (t) << PTXSHIFT | (o)))
+#define PGADDR(d, t, o) ((uint)((d) << PDXSHIFT | (t) << PTXSHIFT | (o)))
 
 // Page directory and page table constants.
-#define NPDENTRIES	1024		// page directory entries per page directory
-#define NPTENTRIES	1024		// page table entries per page table
+#define NPDENTRIES      1024            // page directory entries per page directory
+#define NPTENTRIES      1024            // page table entries per page table
 #define PGSIZE          4096            // bytes mapped by a page
 
 #define PGSHIFT         12              // log2(PGSIZE)
-#define PTXSHIFT	12		// offset of PTX in a linear address
-#define PDXSHIFT	22		// offset of PDX in a linear address
+#define PTXSHIFT        12              // offset of PTX in a linear address
+#define PDXSHIFT        22              // offset of PDX in a linear address
 
 #define PGROUNDUP(sz)  (((sz)+PGSIZE-1) & ~(PGSIZE-1))
 #define PGROUNDDOWN(a) (((a)) & ~(PGSIZE-1))
 
 // Page table/directory entry flags.
-#define PTE_P		0x001	// Present
-#define PTE_W		0x002	// Writeable
-#define PTE_U		0x004	// User
-#define PTE_PWT		0x008	// Write-Through
-#define PTE_PCD		0x010	// Cache-Disable
-#define PTE_A		0x020	// Accessed
-#define PTE_D		0x040	// Dirty
-#define PTE_PS		0x080	// Page Size
-#define PTE_MBZ		0x180	// Bits must be zero
+#define PTE_P           0x001   // Present
+#define PTE_W           0x002   // Writeable
+#define PTE_U           0x004   // User
+#define PTE_PWT         0x008   // Write-Through
+#define PTE_PCD         0x010   // Cache-Disable
+#define PTE_A           0x020   // Accessed
+#define PTE_D           0x040   // Dirty
+#define PTE_PS          0x080   // Page Size
+#define PTE_MBZ         0x180   // Bits must be zero
 
 // Address in page table or page directory entry
-#define PTE_ADDR(pte)	((uint)(pte) & ~0xFFF)
+#define PTE_ADDR(pte)   ((uint)(pte) & ~0xFFF)
 
 #ifndef __ASSEMBLER__
 typedef uint pte_t;
diff --git a/vm.c b/vm.c
index 59c95ca..32775a1 100644
--- a/vm.c
+++ b/vm.c
@@ -137,7 +137,7 @@ setupkvm(char* (*alloc)(void))
     panic("PHYSTOP too high");
   for(k = kmap; k < &kmap[NELEM(kmap)]; k++)
     if(mappages(pgdir, k->virt, k->phys_end - k->phys_start, (uint)k->phys_start, 
-		k->perm, alloc) < 0)
+                k->perm, alloc) < 0)
       return 0;
 
   return pgdir;