source: trunk/INCLUDE/ASM.INC@ 45

; AiR-BOOT (c) Copyright 1998-2008 M. Kiewitz
;
; This file is part of AiR-BOOT
;
; AiR-BOOT is free software: you can redistribute it and/or modify it under
;  the terms of the GNU General Public License as published by the Free
;  Software Foundation, either version 3 of the License, or (at your option)
;  any later version.
;
; AiR-BOOT is distributed in the hope that it will be useful, but WITHOUT ANY
;  WARRANTY: without even the implied warranty of MERCHANTABILITY or FITNESS
;  FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
;  details.
;
; You should have received a copy of the GNU General Public License along with
;  AiR-BOOT. If not, see <http://www.gnu.org/licenses/>.
;
; Some Standard macros to make life easier with ALP and other assemblers :D

MPush Macro reglist
   irp reg,<reglist>
      push    reg
   EndM
EndM

MPop Macro reglist
   irp reg,<reglist>
      pop     reg
   EndM
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


;
; 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
;        incorrect. Tasm with multiple passes works correct.
; FIXME: Get JWasm and Tasm use some common ECHO/%OUT method.
;        (Tasm only pases first word of non-quoted string to a macro)
check_overlap   MACRO   loc

    ; Exit macro immediately if no overlap.
    ; We don't want to assign values to z_last_... if there is no
    ; overlap because they would then hold the values the last time this
    ; macro was called and not those of the last overlap.
    IF (loc - $) LE 0
    ;~ IF ($ - loc) GE 0
        EXITM
    ENDIF

    ; Calculate the overlap.
    z_last_overlap_size = (loc - $)
    z_last_overlap_location = loc - z_last_overlap_size

    IFDEF   JWASM
        ; Output message.
        ECHO
        ECHO ** ERROR: LOCATION OVERLAP DETECTED [JWASM] ! **
        ECHO .         THIS IS MOST LIKELY CAUSED BY CODE / DATA
        ECHO .         EXPANSION TOWARDS AN 'ORG' DIRECTIVE.
        ECHO .         LOOK AT 'z_last_overlap_location' TO SEE WHERE.
        ECHO .         LOOK AT 'z_last_overlap_size' TO SEE SIZE.
        ECHO .         FORCING ERROR...
        ECHO
    ENDIF
    IFDEF   TASM
        IF2
            ; Output message (only on pass2).
            %OUT
            %OUT ** ERROR: LOCATION OVERLAP DETECTED [TASM] ! **
            %OUT .         THIS IS MOST LIKELY CAUSED BY CODE / DATA
            %OUT .         EXPANSION TOWARDS AN 'ORG' DIRECTIVE.
            %OUT .         LOOK AT 'z_last_overlap_location' TO WHERE.
            %OUT .         LOOK AT 'z_last_overlap_size' TO SEE SIZE.
            %OUT .         FORCING ERROR...
            %OUT
        ENDIF
    ENDIF

    ; 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



; Shortcuts for pointer-types
bptr                             equ   byte ptr
wptr                             equ   word ptr
dptr                             equ  dword ptr
qptr                             equ  qword ptr
tptr                             equ  tbyte ptr


sector_size                      equ   512
image_size_60secs                equ   7800h
image_size_62secs                equ   7c00h

;image_size                       equ   image_size_60secs
image_size                       equ   image_size_62secs

sector_count                     equ   image_size / sector_size                  ; Image size in sectors

IF image_size EQ image_size_60secs
   partition_count               equ   30                                        ; Maximum number of partitions supported
ELSE
   partition_count               equ   45                                        ; Maximum number of partitions supported
ENDIF