;****************************************************************************
;*
;*  ========================================================================
;*
;*   Copyright (C) 1991-2002 SciTech Software, Inc. All rights reserved.
;*
;*   This file may be distributed and/or modified under the terms of the
;*   GNU Lesser General Public License version 2.1 as published by the Free
;*   Software Foundation and appearing in the file LICENSE.LGPL included
;*   in the packaging of this file.
;*
;*   Licensees holding a valid Commercial License for this product from
;*   SciTech Software, Inc. may use this file in accordance with the
;*   Commercial License Agreement provided with the Software.
;*
;*   This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING
;*   THE WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
;*   PURPOSE.
;*
;*   See http://www.scitechsoft.com/license/ for information about
;*   the licensing options available and how to purchase a Commercial
;*   License Agreement.
;*
;*   Contact license@scitechsoft.com if any conditions of this licensing
;*   are not clear to you, or you have questions about licensing options.
;*
;*  ========================================================================
;*
;* Language:    NetWide Assembler (NASM)
;* Environment: Any Intel IA32 Environment
;*
;* Description: Macros to provide memory model independant assembly language
;*              module for C programming. Supports the large and flat memory
;*              models.
;*
;*              The defines that you should use when assembling modules that
;*              use this macro package are:
;*
;*                  __FLAT__    Assemble for 32-bit FLAT memory model
;*                  __NOU__     No underscore for all external C labels
;*                  __NOU_VAR__ No underscore for global variables only
;*
;*              The default settings are for 16-bit large memory model with
;*              leading underscores for symbol names.
;*
;****************************************************************************

%ifndef SCITECH_MAC
%define SCITECH_MAC

; Turn off underscores for globals if disabled for all externals

%ifdef  __NOU__
%define __NOU_VAR__
%endif

; Determine if we should use COFF style segment naming

%ifdef __MSC__
%define __COFF__
%endif
%ifdef __GNUC__
%define __COFF__
%endif

; Define the __WINDOWS__ symbol if we are compiling for any Windows
; environment

%ifdef  __WINDOWS16__
%define __WINDOWS__         1
%endif
%ifdef  __WINDOWS32__
%define __WINDOWS__         1
%define __WINDOWS32_386__   1
%endif

; Macros for accessing 'generic' registers

%ifdef  __FLAT__
%idefine _ax    eax
%idefine _bx    ebx
%idefine _cx    ecx
%idefine _dx    edx
%idefine _si    esi
%idefine _di    edi
%idefine _bp    ebp
%idefine _sp    esp
%idefine _es
%idefine UCHAR  BYTE        ; Size of a character
%idefine USHORT WORD        ; Size of a short
%idefine UINT   DWORD       ; Size of an integer
%idefine ULONG  DWORD       ; Size of a long
%idefine BOOL   DWORD       ; Size of a boolean
%idefine DPTR   DWORD       ; Size of a data pointer
%idefine FDPTR  FWORD       ; Size of a far data pointer
%idefine NDPTR  DWORD       ; Size of a near data pointer
%idefine CPTR   DWORD       ; Size of a code pointer
%idefine FCPTR  FWORD       ; Size of a far code pointer
%idefine NCPTR  DWORD       ; Size of a near code pointer
%idefine FPTR   NEAR        ; Distance for function pointers
%idefine DUINT  dd          ; Declare a integer variable
%idefine intsize 4
%idefine flatmodel 1
%else
%idefine _ax    ax
%idefine _bx    bx
%idefine _cx    cx
%idefine _dx    dx
%idefine _si    si
%idefine _di    di
%idefine _bp    bp
%idefine _sp    sp
%idefine _es    es:
%idefine UCHAR  BYTE        ; Size of a character
%idefine USHORT WORD        ; Size of a short
%idefine UINT   WORD        ; Size of an integer
%idefine ULONG  DWORD       ; Size of a long
%idefine BOOL   WORD        ; Size of a boolean
%idefine DPTR   DWORD       ; Size of a data pointer
%idefine FDPTR  DWORD       ; Size of a far data pointer
%idefine NDPTR  WORD        ; Size of a near data pointer
%idefine CPTR   DWORD       ; Size of a code pointer
%idefine FCPTR  DWORD       ; Size of a far code pointer
%idefine NCPTR  WORD        ; Size of a near code pointer
%idefine FPTR   FAR         ; Distance for function pointers
%idefine DUINT  dw          ; Declare a integer variable
%idefine intsize 2
%endif
%idefine invert ~
%idefine offset
%idefine use_nasm

; Convert all jumps to near jumps, since NASM does not so this automatically

%idefine jo     jo near
%idefine jno    jno near
%idefine jz     jz near
%idefine jnz    jnz near
%idefine je     je near
%idefine jne    jne near
%idefine jb     jb  near
%idefine jbe    jbe near
%idefine ja     ja  near
%idefine jae    jae near
%idefine jl     jl  near
%idefine jle    jle near
%idefine jg     jg  near
%idefine jge    jge near
%idefine jc     jc  near
%idefine jnc    jnc near
%idefine js     js  near
%idefine jns    jns near

%ifdef  DOUBLE
%idefine    REAL    QWORD
%idefine    DREAL   dq
%else
%idefine    REAL    DWORD
%idefine    DREAL   dd
%endif

; Boolean truth values (same as those in debug.h)

%idefine False      0
%idefine True       1
%idefine No         0
%idefine Yes        1
%idefine Yes        1

; TODO: If we wish to port VxD code to NASM, we will potentially
;       need special macros in here to handle this!

; Setup all correct segment definitions and attributes once at the
; beginning of the assembler module. This allows us to open/close
; code and data segments at will throughout the code as necessary.

%ifdef __PIC__
%ifdef __LINUX__
        extern _GLOBAL_OFFSET_TABLE_
%else
        extern __GLOBAL_OFFSET_TABLE_
%endif
%endif
%ifdef __COFF__
segment .text public class=CODE use32 flat
segment .data public class=DATA use32 flat
%else
%ifdef flatmodel
segment _TEXT public align=16 class=CODE use32 flat
segment _DATA public align=4 class=DATA use32 flat
%else
segment _TEXT public align=16 class=CODE use16
segment _DATA public align=4 class=DATA use16
%endif
%endif

; Macro to be invoked at the start of all modules to set up segments for
; later use. This does nothing for 32-bit code, but for 16-bit code
; will set up a far model code segment as well for later use.

%imacro header 1
%ifndef flatmodel
segment %1_TEXT public align=16 class=CODE use16
%endif
%endmacro

; Macro to begin a data segment. Segment attributes were specified in
; the header macro that is always required.

%imacro begdataseg 1
%ifdef __COFF__
segment .data
%else
segment _DATA
%endif
%endmacro

; Macro to end a data segment

%imacro enddataseg 1
%endmacro

; Macro to begin a code segment

%imacro begcodeseg 1
%ifdef __COFF__
segment .text
%else
%ifdef flatmodel
segment _TEXT
%else
segment %1_TEXT
%endif
%endif
%endmacro

; Macro to end a code segment

%imacro endcodeseg 1
%endmacro

; Macro to begin a near code segment

%imacro begcodeseg_near 0
%ifdef __COFF__
segment .text
%else
segment _TEXT
%endif
%endmacro

; Macro to end a near code segment

%imacro endcodeseg_near 0
%endmacro

; Macro for an extern C symbol. If the C compiler requires leading
; underscores, then the underscores are added to the symbol names, otherwise
; they are left off. The symbol name is referenced in the assembler code
; using the non-underscored symbol name.

%imacro cextern 2
%ifdef  __NOU_VAR__
extern %1
%else
extern _%1
%define %1 _%1
%endif
%endmacro

%imacro cexternfunc 2
%ifdef  __NOU__
extern %1
%else
extern _%1
%define %1 _%1
%endif
%endmacro

; Macro for a public C symbol. If the C compiler requires leading
; underscores, then the underscores are added to the symbol names, otherwise
; they are left off. The symbol name is referenced in the assembler code
; using the non-underscored symbol name.

%imacro cpublic 1
%ifdef  __NOU_VAR__
global %1
%1:
%else
global _%1
_%1:
%define %1 _%1
%endif
%endmacro

; Macro for an global C symbol. If the C compiler requires leading
; underscores, then the underscores are added to the symbol names, otherwise
; they are left off. The symbol name is referenced in the assembler code
; using the non-underscored symbol name.

%imacro cglobal 1
%ifdef  __NOU_VAR__
global %1
%else
global _%1
%define %1 _%1
%endif
%endmacro

; Macro for an global C function symbol. If the C compiler requires leading
; underscores, then the underscores are added to the symbol names, otherwise
; they are left off. The symbol name is referenced in the assembler code
; using the non-underscored symbol name.

%imacro cglobalfunc 1
%ifdef __PIC__
global %1:function
%else
%ifdef  __NOU__
global %1
%else
global _%1
%define %1 _%1
%endif
%endif
%endmacro

; Macro to start a C callable function. This will be a far function for
; 16-bit code, and a near function for 32-bit code.

%imacro cprocstatic 1
%push cproc
%1:
%ifdef flatmodel
%stacksize flat
%define ret retn
%else
%stacksize large
%define ret retf
%endif
%assign %$localsize 0
%endmacro

%imacro cprocstart 1
%push cproc
    cglobalfunc %1
%1:
%ifdef flatmodel
%stacksize flat
%define ret retn
%else
%stacksize large
%define ret retf
%endif
%assign %$localsize 0
%endmacro

; This macro sets up a procedure to be exported from a 16 bit DLL. Since the
; calling conventions are always _far _pascal for 16 bit DLL's, we actually
; rename this routine with an extra underscore with 'C' calling conventions
; and a small DLL stub will be provided by the high level code to call the
; assembler routine.

%imacro cprocstartdll16 1
%ifdef  __WINDOWS16__
cprocstart  _%1
%else
cprocstart  %1
%endif
%endmacro

; Macro to start a C callable near function.

%imacro cprocnear 1
%push cproc
    cglobalfunc %1
%1:
%define ret retn
%ifdef flatmodel
%stacksize flat
%else
%stacksize small
%endif
%assign %$localsize 0
%endmacro

; Macro to start a C callable far function.

%imacro cprocfar 1
%push cproc
    cglobalfunc %1
%1:
%define ret retf
%ifdef flatmodel
%stacksize flat
%else
%stacksize large
%endif
%assign %$localsize 0
%endmacro

; Macro to end a C function

%imacro cprocend 0
%pop
%endmacro

; Macros for entering and exiting C callable functions. Note that we must
; always save and restore the SI and DI registers for C functions, and for
; 32 bit C functions we also need to save and restore EBX and clear the
; direction flag.

%imacro enter_c 0
        push    _bp
        mov     _bp,_sp
%ifnidn %$localsize,0
        sub     _sp,%$localsize
%endif
%ifdef  flatmodel
        push    ebx
%endif
        push    _si
        push    _di
%endmacro

%imacro leave_c 0
        pop     _di
        pop     _si
%ifdef  flatmodel
        pop     ebx
        cld
%endif
%ifnidn %$localsize,0
        mov     _sp,_bp
%endif
        pop     _bp
%endmacro

%imacro   use_ebx 0
%ifdef flatmodel
        push    ebx
%endif
%endmacro

%imacro   unuse_ebx 0
%ifdef flatmodel
        pop     ebx
%endif
%endmacro

; Macros for saving and restoring the value of DS,ES,FS,GS when it is to
; be used in assembly routines. This evaluates to nothing in the flat memory
; model, but is saves and restores DS in the large memory model.

%imacro use_ds 0
%ifndef flatmodel
        push    ds
%endif
%endmacro

%imacro unuse_ds 0
%ifndef flatmodel
        pop     ds
%endif
%endmacro

%imacro use_es 0
%ifndef flatmodel
        push    es
%endif
%endmacro

%imacro unuse_es 0
%ifndef flatmodel
        pop     es
%endif
%endmacro

; Macros for loading the address of a data pointer into a segment and
; index register pair. The %imacro explicitly loads DS or ES in the 16 bit
; memory model, or it simply loads the offset into the register in the flat
; memory model since DS and ES always point to all addressable memory. You
; must use the correct _REG (ie: _BX) %imacros for documentation purposes.

%imacro _lds    2
%ifdef flatmodel
        mov     %1,%2
%else
        lds     %1,%2
%endif
%endmacro

%imacro   _les  2
%ifdef flatmodel
        mov     %1,%2
%else
        les     %1,%2
%endif
%endmacro

; Macros for adding and subtracting a value from registers. Two value are
; provided, one for 16 bit modes and another for 32 bit modes (the extended
; register is used in 32 bit modes).

%imacro   _add  3
%ifdef flatmodel
        add     e%1, %3
%else
        add     %1, %2
%endif
%endmacro

%imacro _sub    3
%ifdef flatmodel
        sub     e%1, %3
%else
        sub     %1, %2
%endif
%endmacro

; Macro to clear the high order word for the 32 bit extended registers.
; This is used to convert an unsigned 16 bit value to an unsigned 32 bit
; value, and will evaluate to nothing in 16 bit modes.

%imacro clrhi   1
%ifdef  flatmodel
        movzx   e%1,%1
%endif
%endmacro

%imacro sgnhi   1
%ifdef  flatmodel
        movsx   e%1,%1
%endif
%endmacro

; Macro to load an extended register with an integer value in either mode

%imacro loadint 2
%ifdef flatmodel
        mov     e%1,%2
%else
        xor     e%1,e%1
        mov     %1,%2
%endif
%endmacro

; Macros to load and store integer values with string instructions

%imacro LODSINT 0
%ifdef flatmodel
        lodsd
%else
        lodsw
%endif
%endmacro

%imacro STOSINT 0
%ifdef flatmodel
        stosd
%else
        stosw
%endif
%endmacro

; Macros to provide resb, resw, resd compatibility with NASM

%imacro dclb 1
times %1 db 0
%endmacro

%imacro dclw 1
times %1 dw 0
%endmacro

%imacro dcld 1
times %1 dd 0
%endmacro

; Macro to get the addres of the GOT for Linux/FreeBSD shared
; libraries into the EBX register.

%imacro     get_GOT 1
            call    %%getgot
%%getgot:   pop     %1
            add     %1,_GLOBAL_OFFSET_TABLE_+$$-%%getgot wrt ..gotpc
%endmacro

; Macro to get the address of a *local* variable that is global to
; a single module in a manner that will work correctly when compiled
; into a Linux shared library. Note that this will *not* work for
; variables that are defined as global to all modules. For that
; use the LEA_G macro

%macro      LEA_L    2
%ifdef __PIC__
        get_GOT %1
        lea     %1,[%1+%2 wrt ..gotoff]
%else
        lea     %1,[%2]
%endif
%endmacro

; Same macro as above but for global variables public to *all*
; modules.

%macro      LEA_G    2
%ifdef __PIC__
        get_GOT %1
        mov     %1,[%1+%2 wrt ..got]
%else
        lea     %1,[%2]
%endif
%endmacro

; macros to declare assembler function stubs for function structures

%imacro BEGIN_STUBS_DEF 2
begdataseg  _STUBS
%ifdef  __NOU_VAR__
extern %1
%define STUBS_START %1
%else
extern _%1
%define STUBS_START _%1
%endif
enddataseg  _STUBS
begcodeseg  _STUBS
%assign off %2
%endmacro

%imacro   DECLARE_STUB  1
%ifdef __PIC__
        global %1:function
%1:
        get_GOT eax
        mov     eax,[eax+STUBS_START wrt ..got]
        jmp     [eax+off]
%else
%ifdef  __NOU__
        global %1
%1:
%else
        global _%1
_%1:
%endif
        jmp     [DWORD STUBS_START+off]
%endif
%assign off off+4
%endmacro

%imacro   SKIP_STUB  1
%assign off off+4
%endmacro

%imacro DECLARE_STDCALL 2
%ifdef  STDCALL_MANGLE
        global _%1@%2
_%1@%2:
%else
%ifdef STDCALL_USCORE
        global _%1
_%1:
%else
        global %1
%1:
%endif
%endif
        jmp     [DWORD STUBS_START+off]
%assign off off+4
%endmacro

%imacro   END_STUBS_DEF 0
endcodeseg  _STUBS
%endmacro

; macros to declare assembler import stubs for binary loadable drivers

%imacro BEGIN_IMPORTS_DEF   1
BEGIN_STUBS_DEF %1,4
%endmacro

ifndef LOCAL_DECLARE_IMP
%imacro   DECLARE_IMP   2
DECLARE_STUB    %1
%endmacro

%imacro   DECLARE_PTR   2
DECLARE_STUB    %1
%endmacro

%imacro   SKIP_IMP   2
SKIP_STUB    %1
%endmacro

%imacro   SKIP_PTR   2
SKIP_STUB    %1
%endmacro

%imacro   SKIP_IMP2   1
DECLARE_STUB    %1
%endmacro

%imacro   SKIP_IMP3   1
SKIP_STUB    %1
%endmacro
endif

%imacro   END_IMPORTS_DEF 0
END_STUBS_DEF
%endmacro

%endif