save a few boot0 bytes

boot0.s

@@ -101,9 +101,8 @@ main:
   or ax, bx
   or eax, eax
   jnz panic
-  ; Load and spill the GPT starting LBA
-  mov ax, [di + 0x48]
-  push ax
+  ; Store the first 16 bits of the GPT starting LBA (we have made sure the remaining bits are 0)
+  push word [di + 0x48]
 
   ; Load number of partitions
   mov ax, [di + 0x50]
@@ -165,11 +164,10 @@ main:
 
   ; Set up stack variables for our second stage search loop.
   xor ax, ax
-  push ax                              ; Current entry
-  push ax                              ; Current entry within the current sector
-  push ax                              ; Number of sectors loaded
-  mov ax, [bp - GPT_ENTRIES_START_LBA]
-  push ax                              ; Current LBA
+  push ax                                ; Current entry
+  push ax                                ; Current entry within the current sector
+  push ax                                ; Number of sectors loaded
+  push word [bp - GPT_ENTRIES_START_LBA] ; Current LBA
 
   ; Search for the partition storing our second stage.
 .loop_find_stage2: