vbr: reduce size for error reporting

boot/fat12vbr.asm

@@ -49,10 +49,12 @@ _startup:
   mov es, ax
   mov ss, ax
   xor sp, sp
-  mov cx, 0x0100
+  ; relocate
   mov si, 0x7C00
   mov di, 0x0500
-  rep movsw ; relocate
+  mov cx, 0x0100
+  rep movsw
+  ; adjust CS
   jmp 0x0000:main
 
 main:
@@ -60,7 +62,7 @@ main:
 
 adjustchs:
   mov ah, 0x08
-  int 0x13 ; required, QEMU detects 360kB as 1200kB with CHS 80 2 15
+  int 0x13
   jc loaddir ; skip if function does not exist
   inc dh
   mov [fdc.nos], dh
@@ -107,24 +109,43 @@ scandir:
   jz found
   add bx, 0x0020 ; 32 bytes per directory entry
   loop .loop
-  call print_inline
+  call error
-  db "File not found", 0x0A, 0x0D, 0
+  db "NOT FOUND", 0
-  jmp hlt
 found:
   add bx, 26
   mov ax, [bx]
   call print16
   jmp hlt
 
+error:
+  call print16
+  pop si
+  mov bx, 0x0000
+  mov al, 0x20
+.loop:
+  mov ah, 0x0e
+  int 0x10
+  lodsb
+  cmp al, 0x00
+  jne .loop
+  ; fall through into htl
+
 hlt:
   hlt
   jmp hlt
 
+; Load a single FAT cluster into memory
+; in	ax	cluster number
+;	bx	buffer
+;
+loadsec:
+
+  ret
+
 ; Load a single block into memory
+; Does not return on error
 ; in    ax      sector number
 ;       bx	buffer
-; out   al      error code,
-;       carry set if error
 loadblk:
   push ax
   push cx
@@ -148,42 +169,8 @@ loadblk:
   ret
 .error:
   xchg al, ah
-  call print_inline
+  call error
-  db "disk error ", 0
+  db "DISK ERROR", 0
-  call print8
-  call print_inline
-  db 0x0A, 0x0D, 0
-  jmp hlt
-
-; in	si
-dump:
-  mov si, bx
-  mov cx, 0x10
-.nextline:
-  mov ax, si
-  call print16
-
-  push si
-  call print_inline
-  db 0x3A, 0x20, 0
-  pop si
-
-  push cx
-  mov cx, 0x0020
-.bytes:
-  lodsb
-  call print8
-  loop .bytes
-  pop cx
-
-  push si
-  call print_inline
-  db 0x0A, 0x0D, 0
-  pop si
-
-  loop .nextline
-
-  ret
 
 %include "print.asm"