asmsubs.c

CC386 is a general-purpose 32-bit C compiler. It is not an optimizing compiler but given that the co

/* 
   Copyright 1994-2003 Free Software Foundation, Inc.

   This program 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 2 of the License, or
   (at your option) any later version.

   This program 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 this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
   02111-1307, USA.  

   You may contact the author at:

   mailto::[e-mail]

   or by snail mail at:

   David Lindauer
   850 Washburn Ave Apt 99
   Louisville, KY 40222
*/
/*                                ASMSUBS.C                                 */

/* had to totally rewrite for 32-bit, DAL */

#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <ctype.h>
#include <dos.h>
#include <string.h>

#include "langext.h"
#include "defines.h"
#include "types.h"
#include "subs.h"

#pragma inline

/*+-------------------------------------------------------------------------+
  |                                                                         |
  |                               checksum                                  |
  |                                                                         |
  +-------------------------------------------------------------------------+*/
bit_16 checksum(bit_32 len, byte *sym)
BeginDeclarations
EndDeclarations
BeginCode
/* The following assembly code is the equivalent of the following C code:
 For i=0; i LessThan len; i++
  BeginFor
   sum += sym[i];
  EndFor;
 return(sum); */

 asm            push    esi
 asm            push    edi
 asm            push    ebx
 asm            mov     esi,[sym]
 asm            mov     ecx,[len]
 asm            xor     eax,eax
 asm            jecxz   hash_x
 asm            mov     ebx,eax
hash_loop:
 asm            mov     bl,[esi]
 asm            add     ax,bx
 asm            inc     esi
 asm            loop    hash_loop
hash_x:
 asm            pop     ebx
 asm            pop     edi
 asm            pop     esi
 return(_EAX);
EndCode

/*+-------------------------------------------------------------------------+
  |                                                                         |
  |                          far_compare                                    |
  |                                                                         |
  +-------------------------------------------------------------------------+*/
int_32 far_compare (byte_ptr left, byte_ptr right, bit_32 len)
BeginDeclarations
EndDeclarations
BeginCode
/* The following assembly code is the equivalent of the following C code:
 While len-- IsNotZero
  BeginWhile
   If *left IsNotEqualTo *right
    Then
     If *left LessThan *right
      Then
       return(-1);
      Else
       return(1);
      EndIf;
    EndIf;
   left++;
   right++;
  EndWhile;
 return(0); */

 asm            push    esi
 asm            push    edi
 asm            cld
 asm            mov     ecx,[len]
 asm            mov     edi,[right]
 asm            mov     esi,[left]
 asm    rep     cmpsb
 asm            pop     edi
 asm            pop     esi
 asm            jb      left_less_than_right
 asm            ja      left_greater_than_right

 return(0);
left_less_than_right:
 return(-1);
left_greater_than_right:
 return(1);
EndCode

/*+-------------------------------------------------------------------------+
  |                                                                         |
  |                            far_index                                    |
  |                                                                         |
  +-------------------------------------------------------------------------+*/
bit_32 far_index(byte_ptr dest, byte c)
BeginDeclarations
bit_32                                 i;
EndDeclarations
BeginCode
/* The following assembly code is the equivalent of the following C code:
 For i=0; (*dest++ IsNotEqualTo c) AndIf (i IsNotEqualTo 0xFFFF); i++
  BeginFor
  EndFor;
 return(i); */

 asm            push    edi
 asm            xor     ecx,ecx
 asm            mov     al,[c]
 asm            mov     edi,[dest]
search_loop:
 asm            cmp     al,[edi]
 asm            je      search_done
 asm            inc     edi
 asm            inc     ecx
 asm            jne     search_loop
 asm            dec     ecx
search_done:
 asm            mov     [i],ecx
 asm            pop     edi

 return(i);
EndCode

/*+-------------------------------------------------------------------------+
  |                                                                         |
  |                              far_match                                  |
  |                                                                         |
  +-------------------------------------------------------------------------+*/
bit_32 far_match (byte_ptr pattern, byte_ptr s, bit_32 len)
BeginDeclarations
EndDeclarations
BeginCode
/* The following assembly code is the equivalent of the following C code:
 While len Exceeds 0
  BeginWhile
   If *pattern Is '*'
    Then
     return(True);
    EndIf;
   If (*pattern IsNot '?') AndIf (*pattern IsNot *source)
    Then
     return(False);
    EndIf;
   source++;
   pattern++;
  EndWhile;
 return(True); */

 asm            push    esi
 asm            push    edi
 asm            mov     ecx,[len]
 asm            mov     edi,[pattern]
 asm            mov     esi,[s]
pattern_loop:
 asm            mov     al,[edi]
 asm            cmp     al,'?'
 asm            je      a_match
 asm            cmp     al,'*'
 asm            je      succeeded
 asm            cmp     al,[esi]
 asm            jne     failed
a_match:
 asm            inc     esi
 asm            inc     edi
 asm            loop    pattern_loop
succeeded:
 asm            pop     edi
 asm            pop     esi
 return(True);
failed:
 asm            pop     edi
 asm            pop     esi
 return(False);
EndCode

/*+-------------------------------------------------------------------------+
  |                                                                         |
  |                          far_move                                       |
  |                                                                         |
  +-------------------------------------------------------------------------+*/
byte_ptr far_move (byte_ptr dest, byte_ptr source, bit_32 len)
BeginDeclarations
EndDeclarations
BeginCode
/* The following assembly code is the equivalent of the following C code:
 While len-- IsNotZero
  BeginWhile
   *dest++ = *source++;
  EndWhile; */

 asm            push    esi
 asm            push    edi
 asm            cld
 asm            mov     ecx,[len]
 asm            mov     edi,[dest]
 asm            mov     esi,[source]
 asm    rep     movsb
 asm            pop     edi
 asm            pop     esi

 return(dest);
EndCode

/*+-------------------------------------------------------------------------+
  |                                                                         |
  |                          far_move_left                                  |
  |                                                                         |
  +-------------------------------------------------------------------------+*/
byte_ptr far_move_left (byte_ptr dest, byte_ptr source, bit_32 len)
BeginDeclarations
EndDeclarations
BeginCode