diff --git a/.gitignore b/.gitignore
index 8d5a1b4..d218281 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,5 @@
 *.o
+*.swp
 /boot.bin
 /boot.elf
 /serve
diff --git a/src/bios.S b/src/bios.S
index 1d35336..091b9bb 100644
--- a/src/bios.S
+++ b/src/bios.S
@@ -31,8 +31,7 @@ bios_write: push        %ebp
             PROT32
 
             pop         %ebx
-            mov         %ebp, %esp
-            pop         %ebp
+            leave
             ret
 
             .global     bios_getmap
@@ -68,8 +67,7 @@ _gmdone:    add         $24, %di
             
             pop         %edi
             pop         %ebx
-            mov         %ebp, %esp
-            pop         %ebp
+            leave
             ret
 
             .global     bios_func
@@ -80,39 +78,38 @@ bios_func:  push        %ebp
             push        %edi
             push        %esi
 
-            mov         8+0(%ebp), %eax
-            mov         8+4(%ebp), %edi
-
             // The interrupt number is given as an immediate value to INT.
             // To support any interrupt number, we use self-modifying code.
+            mov         8+0(%ebp), %eax
             mov         %al, _bf_int+1
 
             PROT16
             REAL
 
-            mov          0(%edi), %eax
-            mov          4(%edi), %ecx
-            mov          8(%edi), %edx
-            mov         12(%edi), %ebx
-            mov         16(%edi), %ebp
-            mov         20(%edi), %esi
-            mov         24(%edi), %edi
+            mov         8+4(%ebp), %edi
+            mov          0(%edi), %ax
+            mov          2(%edi), %cx
+            mov          4(%edi), %dx
+            mov          6(%edi), %bx
+            mov          8(%edi), %bp
+            mov         10(%edi), %si
+            mov         12(%edi), %di
 
             // This instruction will get written at runtime
 _bf_int:    .byte       0xCD, 0 // INT imm8
             push        $0
             pushf
 
-            push        %edi
+            push        %di
             mov         8+4(%ebp), %edi
-            mov         %eax,  0(%edi)
-            mov         %ecx,  4(%edi)
-            mov         %edx,  8(%edi)
-            mov         %ebx, 12(%edi)
-            mov         %ebp, 16(%edi)
-            mov         %esi, 20(%edi)
-            pop         %eax
-            mov         %eax, 24(%edi)
+            mov         %ax,  0(%edi)
+            mov         %cx,  2(%edi)
+            mov         %dx,  4(%edi)
+            mov         %bx,  6(%edi)
+            mov         %bp,  8(%edi)
+            mov         %si, 10(%edi)
+            pop         %ax
+            mov         %ax, 12(%edi)
 
             PROT
             PROT32
@@ -123,6 +120,5 @@ _bf_int:    .byte       0xCD, 0 // INT imm8
             pop         %edi
             pop         %ebp
             pop         %ebx
-            mov         %ebp, %esp
-            pop         %ebp
+            leave
             ret
diff --git a/src/main.c b/src/main.c
index 6adb5ed..576f4d4 100644
--- a/src/main.c
+++ b/src/main.c
@@ -49,7 +49,7 @@ struct vesa_info {
 	uint8_t reserved[492];
 };
 
-extern uint16_t bios_func(uint8_t inum, uint32_t reg[]);
+extern uint16_t bios_func(uint8_t inum, uint16_t reg[]);
 
 #define PG_PRESENT 0x001
 #define PG_WRITE   0x002
@@ -123,7 +123,7 @@ main()
 	bios_write(buf);
 #endif
 
-	uint32_t reg[7];
+	uint16_t reg[7];
 	reg[0] = (0x0E << 8) + 'J';
 	reg[1] = 0;
 	reg[2] = 0;