Changeset 135 for trunk/bootcode/regular/other.asm

Timestamp:

Apr 8, 2017, 12:27:33 AM (8 years ago)

Author:

Ben Rietbroek

Message:

Clear the variable area using new fill function [v1.1.1-testing]

CAUTION:
This is a testbuild !
AirBoot uses the BIOS to access disks and a small coding error can trash
partition tables or other vital disk structures. You are advised to make
backups of TRACK0 and EBRs before using this testbuild. More info at:
​https://rousseaux.github.io/netlabs.air-boot/pdf/AirBoot-v1.1.0-manual.pdf

File:

• trunk/bootcode/regular/other.asm (modified) (1 diff)

trunk/bootcode/regular/other.asm

@@ -100 +100 @@
 ENDIF
 
-        ; First initialize Variable-Area (everything with NUL)
-        ; We use the start instead of the variables because they could be 'orged'
-        ; to an offset. We want everything after the code to be nullified.
-        mov     di, offset sobss
+        ; Clear the BSS from its real start just upto the end of the variables.
+        ; Here 'real start' means from where the BSS begins, which is below
+        ; the point where the first variables are located. The part after
+        ; the variables is not cleared because that is where the old SS:SP is
+        ; stored, which is needed for AirBoot restarts during debugging.
+        mov     bx, offset sobss
         mov     cx, offset EndOfVariables - offset sobss
         xor     ax, ax
-        shr     cx, 1
-        inc     cx
-        rep     stosw
-
+        call    FillMemBlock
 
     ;