Changeset 45 for trunk/INCLUDE/ASM.INC

Timestamp:

Apr 12, 2014, 12:36:45 AM (11 years ago)

Author:

Ben Rietbroek

Message:

Now using compressed HidePartTable (auxdebug on) [2012-02-24]

WARNING!!

All commits upto and including the commit of [2012-05-13] contain
a severe bug!! Building from these sources and then disabling
the 'force LBA' feature while also using the drive-letter feature or
editing the label can DESTROY THE MBR on ALL ATTACHED DISKS!!
DO NOT DISABLE 'FORCE LBA USAGE' WHEN BUILT FROM THE THESE COMMITS!!

Fixes

o HidePartTabled now uses a 6-bit compressed format

Bitfield functions are used to manipulate the table.
Modifications mostly in PARTSCAN.ASM, PART_SET.ASM and PARTMAIN.ASM.
TODO: Determine impact on upgrading from previous versions.

Changes

o Changed LVM Label behavior

If they are the same, the LVM VolumeName is synced to LVM PartitionName
so they are the same again after the edit.
If they differ, only the LVM VolumeName is updated.

o Implemented stop scanning when partition limit of 45 is exceeded

User is presented with a warning pop-up.
Pressing a key will continue and the partitions that were found
so far are displayed in the menu.
The color of the selection bar is changed to red to indicate this
overflow situation.

o New overlap macro that works correctly with JWasm and Tasm

Now uses DB n DUP (<filler>) to fill space before a new ORG.
When overlap occurs n goes negative causing assembler error.

File:

• trunk/INCLUDE/ASM.INC (modified) (2 diffs)

trunk/INCLUDE/ASM.INC

@@ -30 +30 @@
 EndM
 
-callfar Macro destination
-   push    cs
-   call    &destination
-EndM
+
+; Rousseau:
+; My editor (Geany) keeps auto-completing 'call' to 'callfar' because
+; of this definition. Since it's not used anywhere I disabled it.
+;~ callfar Macro destination
+   ;~ push    cs
+   ;~ call    &destination
+;~ EndM
 
 
 ;
-; An ORG directive resets the location counter where code and data is
-; generated. If the location counter is reset back to a point where
-; code or data already has been generated, this will be overwritten
-; without warning.
-; This macro can be used with every ORG directive to check for this condition,
-; and when it occurs further assembly is terminated.
-
+; OLD OVERLAP CHECKER, DOES NOT WORK WELL WITH JWASM.
+;
 ; NOTE:  Overlapchecking in JWasm is not as reliable as in Tasm.
 ;        Because it's a single pass assembler, the current location can be
@@ -91 +90 @@
     ; Terminate assembly by forcing an error.
     .ERR
+ENDM
 
+
+;
+; A normal ORG directive resets the location counter where code and data is
+; going to be emitted. If the location counter is reset back to a point
+; where code or data already has been emitted, this will be overwritten
+; without warning.
+; This macro does a check for this condition and aborts if it exists.
+; If there is space between the new location and the last emitted code or data
+; will be filled.
+;
+; There are differences between assemblers on when and how labels and values
+; are evaluated. Since JWasm is a single-pass assembler, some expressions
+; do not work that do work in multi-pass Tasm.
+; That's why the actual check for overlap is done by db getting a negative
+; value if an overlap occured.
+; So don't change the (after - before) calculations by assigning it to a
+; variable; that will break this macro.
+;
+ORIGIN  MACRO   loc
+    ;~ IFDEF   JWASM
+        ;~ db  (@F - $)   dup('X')
+        ;~ ORG     loc
+        ;~ @@:
+    ;~ ENDIF
+
+    ; Use this value to fill the gap between the new origin and the last
+    ; emitted code or data.
+    fillchar = 'X'
+
+    ; Mark the location of the last emitted code or data.
+    z_&loc&_1before:
+
+    ; JWasm can do db 0 dup (0).
+    IFDEF   JWASM
+        db  (z_&loc&_2after - z_&loc&_1before)   dup(fillchar)
+    ENDIF
+
+    ; Tasm cannot.
+    IFDEF   TASM
+        IF (z_&loc&_2after - z_&loc&_1before) NE 0
+            db  (z_&loc&_2after - z_&loc&_1before)   dup(fillchar)
+        ENDIF
+    ENDIF
+
+    ; Set the new origin.
+    ORG     loc
+
+    ; Mark the new location.
+    z_&loc&_2after:
+
+    ; Calculate the gap.
+    z_&loc&_3gap = z_&loc&_2after - z_&loc&_1before
+
+    ;
+    ; Note that the variables are prefixed with z_ so they appear
+    ; at the end of the list-file.
+    ;
 ENDM
+