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FreeDOS/kernel/asmsupt.asm
Bart Oldeman be2ae12b54 See history.txt for the list of fixes. 
git-svn-id: https://svn.code.sf.net/p/freedos/svn/kernel/trunk@196 6ac86273-5f31-0410-b378-82cca8765d1b
2001-04-15 03:21:50 +00:00

460 lines
12 KiB
NASM
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; File:
; asmsupt.asm
; Description:
; Assembly support routines for miscellaneous functions
;
; Copyright (c) 1995, 1998
; Pasquale J. Villani
; All Rights Reserved
;
; This file is part of DOS-C.
;
; DOS-C 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, or (at your option) any later version.
;
; DOS-C 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 DOS-C; see the file COPYING. If not,
; write to the Free Software Foundation, 675 Mass Ave,
; Cambridge, MA 02139, USA.
;
; version 1.4 by tom.ehlert@ginko.de
; added some more functions
; changed bcopy, scopy, sncopy,...
; to memcpy, strcpy, strncpy
; Bart Oldeman: optimized a bit: see /usr/include/bits/string.h from
; glibc 2.2
;
; $Id$
;
; $Log$
; Revision 1.5 2001/04/15 03:21:50 bartoldeman
; See history.txt for the list of fixes.
;
; Revision 1.4 2001/03/21 02:56:25 bartoldeman
; See history.txt for changes. Bug fixes and HMA support are the main ones.
;
; Revision 1.3 2000/05/25 20:56:21 jimtabor
; Fixed project history
;
; Revision 1.2 2000/05/08 04:29:59 jimtabor
; Update CVS to 2020
;
; Revision 1.1.1.1 2000/05/06 19:34:53 jhall1
; The FreeDOS Kernel. A DOS kernel that aims to be 100% compatible with
; MS-DOS. Distributed under the GNU GPL.
;
; Revision 1.3 1999/08/10 17:57:12 jprice
; ror4 2011-02 patch
;
; Revision 1.2 1999/04/23 04:24:39 jprice
; Memory manager changes made by ska
;
; Revision 1.1.1.1 1999/03/29 15:40:41 jprice
; New version without IPL.SYS
;
; Revision 1.4 1999/02/08 05:55:57 jprice
; Added Pat's 1937 kernel patches
;
; Revision 1.3 1999/02/01 01:48:41 jprice
; Clean up; Now you can use hex numbers in config.sys. added config.sys screen function to change screen mode (28 or 43/50 lines)
;
; Revision 1.2 1999/01/22 04:13:25 jprice
; Formating
;
; Revision 1.1.1.1 1999/01/20 05:51:01 jprice
; Imported sources
;
; Rev 1.4 06 Dec 1998 8:46:50 patv
; Bug fixes.
;
; Rev 1.3 03 Jan 1998 8:36:44 patv
; Converted data area to SDA format
;
; Rev 1.2 29 May 1996 21:03:38 patv
; bug fixes for v0.91a
;
; Rev 1.1 01 Sep 1995 17:54:26 patv
; First GPL release.
;
; Rev 1.0 05 Jul 1995 11:38:42 patv
; Initial revision.
; $EndLog$
;
%include "segs.inc"
segment HMA_TEXT
;*********************************************************************
; this implements some of the common string handling functions
;
; every function has 1 entry
;
; NEAR FUNC()
;
; currently done:
;
; memcpy(void *dest, void *src, int count)
; fmemcpy(void FAR *dest, void FAR *src, int count)
; _fmemcpy(void FAR *dest, void FAR *src, int count)
; fmemset(void FAR *dest, int ch, int count);
; fstrncpy(void FAR*dest, void FAR *src, int count);
; strcpy (void *dest, void *src);
; fstrcpy (void FAR*dest, void FAR *src, int count);
; strlen (void *dest);
; fstrlen (void FAR*dest);
; strchr (BYTE *src , BYTE ch);
; fstrcmp (BYTE FAR *s1 , BYTE FAR *s2);
; strcmp (BYTE *s1 , BYTE *s2);
; fstrncmp(BYTE FAR *s1 , BYTE FAR *s2, int count);
; strncmp(BYTE *s1 , BYTE *s2, int count);
;***********************************************
; common_setup - set up the standard calling frame for C-functions
; and save registers needed later
; also preload the args for the near functions
; di=arg1
; si=arg2
; cx=arg3
;
common_setup:
pop bx ; get return address
push bp ; Standard C entry
mov bp,sp
push si
push di
push es
push ds
; Set both ds and es to same segment (for near copy)
pop es
push ds
; Set direction to autoincrement
cld
; to conserve even some more bytes,
; the registers for the near routines
; are preloaded here
; the destination pointer, d = arg1
mov di,[bp+4]
; Get the source pointer, s = arg2
mov si,[bp+6]
; Get the repitition count, n = arg3
mov cx,[bp+8]
jmp bx
;***********************************************
;
; VOID memcpy(REG BYTE *s, REG BYTE *d, REG COUNT n);
;
global _memcpy
_memcpy:
call common_setup
domemcpy:
; And do the built-in byte copy, but do a 16-bit transfer
; whenever possible.
shr cx,1
rep movsw
jnc common_return
movsb
;
; common_return - pop saved registers and do return
;
common_return:
pop ds
pop es
pop di
pop si
pop bp
ret
;************************************************************
;
; VOID fmemcpy(REG BYTE FAR *d, REG BYTE FAR *s,REG COUNT n);
;
global __fmemcpy
global _fmemcpy
_fmemcpy:
__fmemcpy:
call common_setup
; Get the far source pointer, s
lds si,[bp+8]
; Get the far destination pointer d
les di,[bp+4]
; Get the repetition count, n
mov cx,[bp+12]
jmp short domemcpy
;***************************************************************
;
; VOID fmemset(REG VOID FAR *d, REG BYTE ch, REG COUNT n);
;
global _fmemset
_fmemset:
call common_setup
; Get the repetition count, n
mov cx,[bp+10]
; Get the far source pointer, s
les di,[bp+4]
; Get the far destination pointer ch
mov al,[bp+8]
domemset:
mov ah, al
shr cx,1
rep stosw
jnc common_return
stosb
jmp short common_return
;***************************************************************
;
; VOID memset(REG VOID *d, REG BYTE ch, REG COUNT n);
;
global _memset
_memset:
call common_setup
; Get the far source pointer, s
; mov di,[bp+4]
; Get the char ch
mov ax,si ; mov al, [bp+6]
; Get the repititon count, n
; mov cx,[bp+8]
jmp short domemset
;***************************************************************
global _fstrncpy
_fstrncpy:
call common_setup
; Get the source pointer, ss
lds si,[bp+8]
; and the destination pointer, d
les di,[bp+4]
mov cx,[bp+12]
jcxz common_return
;; dec cx
; jcxz store_one_byte
strncpy_loop: lodsb
stosb
test al,al
loopnz strncpy_loop
store_one_byte: xor al,al
; the spec for strncpy() would require
; rep stosb
; to fill remaining part of buffer
stosb
jmp short common_return
;*****************************************************************
global _fstrcpy
_fstrcpy:
call common_setup
; Get the source pointer, ss
lds si,[bp+8]
; and the destination pointer, d
les di,[bp+4]
jmp short dostrcpy
;******
global _strcpy
_strcpy:
call common_setup
; Get the source pointer, ss
;mov si,[bp+6]
; and the destination pointer, d
;mov di,[bp+4]
dostrcpy:
strcpy_loop:
lodsb
stosb
test al,al
jne strcpy_loop
jmp short common_return
;******************************************************************
global _fstrlen
_fstrlen:
call common_setup
; Get the source pointer, ss
les di,[bp+4]
jmp short dostrlen
;**********************************************
global _strlen
_strlen:
call common_setup
; The source pointer, ss, arg1 was loaded as di
dostrlen:
mov al,0
mov cx,0xffff
repne scasb
mov ax,cx
not ax
dec ax
jmp short common_return
;************************************************************
global _strchr
_strchr:
call common_setup
; Get the source pointer, ss
; mov si,[bp+4]
; mov bx,[bp+6]
mov bx,si
mov si,di
strchr_loop:
lodsb
cmp al,bl
je strchr_found
test al,al
jne strchr_loop
mov si,1 ; return NULL if not found
strchr_found:
mov ax,si
dec ax
jmp common_return
;**********************************************************************
global _fstrcmp
_fstrcmp:
call common_setup
; Get the source pointer, ss
lds si,[bp+4]
; and the destination pointer, d
les di,[bp+8]
jmp dostrcmp
;******
global _strcmp
_strcmp:
call common_setup
; Get the source pointer, ss
; mov si,[bp+4]
; and the destination pointer, d
; mov di,[bp+6]
xchg si,di
dostrcmp:
; replace strncmp(s1,s2)-->
; strncmp(s1,s2,0xffff)
mov cx,0xffff
jmp short dostrncmp
;**********************************************************************
global _fstrncmp
_fstrncmp:
call common_setup
; Get the source pointer, ss
lds si,[bp+4]
; and the destination pointer, d
les di,[bp+8]
mov cx,[bp+10]
jmp short dostrncmp
;******
global _strncmp
_strncmp:
call common_setup
; Get the source pointer, ss
;mov si,[bp+4]
; and the destination pointer, d
;mov di,[bp+6]
;mov cx,[bp+8]
xchg si,di
dostrncmp:
jcxz strncmp_retzero
strncmp_loop:
lodsb
scasb
jne strncmp_done
test al,al
loopne strncmp_loop
strncmp_retzero:
xor ax, ax
jmp short strncmp_done2
strncmp_done:
sbb ax,ax
or al,1
strncmp_done2: jmp common_return
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