214 lines
9.2 KiB
NASM
214 lines
9.2 KiB
NASM
;*****************************************************************************
|
|
;*
|
|
;* Open Watcom Project
|
|
;*
|
|
;* Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
|
|
;*
|
|
;* ========================================================================
|
|
;*
|
|
;* This file contains Original Code and/or Modifications of Original
|
|
;* Code as defined in and that are subject to the Sybase Open Watcom
|
|
;* Public License version 1.0 (the 'License'). You may not use this file
|
|
;* except in compliance with the License. BY USING THIS FILE YOU AGREE TO
|
|
;* ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
|
|
;* provided with the Original Code and Modifications, and is also
|
|
;* available at www.sybase.com/developer/opensource.
|
|
;*
|
|
;* The Original Code and all software distributed under the License are
|
|
;* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
|
|
;* EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM
|
|
;* ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
|
|
;* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR
|
|
;* NON-INFRINGEMENT. Please see the License for the specific language
|
|
;* governing rights and limitations under the License.
|
|
;*
|
|
;* ========================================================================
|
|
;*
|
|
;* Description: Intel 386 implementation strcmp().
|
|
;*
|
|
;*****************************************************************************
|
|
|
|
|
|
include mdef.inc
|
|
include struct.inc
|
|
|
|
ifdef _PROFILE
|
|
include p5prof.inc
|
|
endif
|
|
|
|
modstart _strcmp,para
|
|
|
|
cmp4 macro off
|
|
mov ebx,off[eax] ; get dword from op1
|
|
mov ecx,off[edx] ; get dword from op2
|
|
cmp ecx,ebx ; compare them
|
|
jne unequal ; quit if not equal
|
|
ife off-12
|
|
add eax,off+4 ; point to next group of dwords
|
|
add edx,off+4 ; ...
|
|
endif
|
|
not ecx ; ...
|
|
add ebx,0FEFEFEFFh ; determine if '\0' is one of bytes
|
|
and ebx,ecx ; ...
|
|
and ebx,80808080h ; ebx will be non-zero if '\0' found
|
|
endm
|
|
|
|
defpe strcmp
|
|
xdefp "C",strcmp
|
|
ifdef _PROFILE
|
|
P5Prolog
|
|
endif
|
|
ifdef __STACK__
|
|
mov eax,4[esp] ; get p1
|
|
mov edx,8[esp] ; get p2
|
|
endif
|
|
cmp eax,edx ; pointers equal ?
|
|
je equalnorst ; yes, return 0
|
|
ifndef __STACK__
|
|
push ecx ; save register
|
|
endif
|
|
test al,3 ; p1 aligned ?
|
|
jne realign ; no, go and realign
|
|
test dl,3 ; p2 aligned ?
|
|
jne slowcpy ; no, do the slow copy (impossible to align both)
|
|
|
|
fastcpy:
|
|
push ebx ; save register
|
|
|
|
align 4
|
|
_loop ; - loop
|
|
cmp4 0 ; - - compare first dword
|
|
_quif ne ; - - quit if end of string
|
|
cmp4 4 ; - - compare second dword
|
|
_quif ne ; - - quit if end of string
|
|
cmp4 8 ; - - compare third dword
|
|
_quif ne ; - - quit if end of string
|
|
cmp4 12 ; - - compare fourth dword
|
|
_until ne ; - until end of string
|
|
equalrst: ; strings equal, restore registers
|
|
pop ebx ; restore register
|
|
ifndef __STACK__
|
|
pop ecx ; ...
|
|
endif
|
|
equalnorst: ; strings equal, skip register restore
|
|
sub eax,eax ; indicate strings equal
|
|
ifdef _PROFILE
|
|
P5Epilog
|
|
endif
|
|
ret ; return
|
|
|
|
unequal: ; dword was not equal
|
|
_guess ; guess strings are equal
|
|
cmp bl,cl ; - check low bytes
|
|
_quif ne ; - quit if not equal
|
|
cmp bl,0 ; - stop if end of string
|
|
je equalrst ; - ...
|
|
cmp bh,ch ; - check next bytes
|
|
_quif ne ; - quit if not equal
|
|
cmp bh,0 ; - stop if end of string
|
|
je equalrst ; - ...
|
|
shr ebx,16 ; - shift top 2 bytes to bottom
|
|
shr ecx,16 ; - ...
|
|
cmp bl,cl ; - check third byte
|
|
_quif ne ; - quit if not equal
|
|
cmp bl,0 ; - stop if end of string
|
|
je equalrst ; - ...
|
|
cmp bh,ch ; - check high order byte
|
|
;; we know at this point that bh != ch, just have to do the compare
|
|
;; _quif ne ; - quit if not equal
|
|
;; cmp bh,0 ; - stop if end of string
|
|
;; je equalrst ; - ...
|
|
_endguess ; endguess
|
|
sbb eax,eax ; eax = 0 if op1>op2, -1 if op1<op2
|
|
or al,1 ; eax = 1 if op1>op2, -1 if op1<op2
|
|
pop ebx ; restore registers
|
|
ifndef __STACK__
|
|
pop ecx ; ...
|
|
endif
|
|
ifdef _PROFILE
|
|
P5Epilog
|
|
endif
|
|
ret ; return
|
|
|
|
align 4
|
|
realign:
|
|
_loop ; - loop
|
|
mov cl,[eax] ; get byte from p1
|
|
inc eax ; point to next byte
|
|
mov ch,[edx] ; get byte from p2
|
|
inc edx ; point to next byte
|
|
cmp cl,ch ; bytes equal?
|
|
jne unequal2 ; unequal, quit
|
|
or cl,cl ; end of string ?
|
|
je equal2 ; yes, quit
|
|
test al,3 ; check alignment
|
|
_until e ; until aligned
|
|
test dl,3 ; p2 aligned ?
|
|
je fastcpy ; yes
|
|
|
|
align 4
|
|
slowcpy:
|
|
_loop
|
|
mov ecx,[eax] ; get aligned 4 bytes
|
|
cmp cl,[edx] ; check 1st byte
|
|
jne unequal2 ; bytes not equal
|
|
or cl,cl ; end of string?
|
|
je equal2 ; yes, quit
|
|
cmp ch,[edx+1] ; check 2nd byte
|
|
jne unequal2 ; bytes not equal
|
|
or ch,ch ; end of string?
|
|
je equal2 ; yes, quit
|
|
shr ecx,16 ; move next pair of bytes to be tested
|
|
cmp cl,[edx+2] ; check 3rd byte
|
|
jne unequal2 ; bytes not equal
|
|
or cl,cl ; end of string?
|
|
je equal2 ; yes, quit
|
|
cmp ch,[edx+3] ; check 4th byte
|
|
jne unequal2 ; bytes not equal
|
|
or ch,ch ; end of string?
|
|
je equal2 ; yes, quit
|
|
mov ecx,[eax+4] ; get next aligned 4 bytes
|
|
cmp cl,[edx+4] ; check 5th byte
|
|
jne unequal2 ; bytes not equal
|
|
or cl,cl ; end of string?
|
|
je equal2 ; yes, quit
|
|
cmp ch,[edx+5] ; check 6th byte
|
|
jne unequal2 ; bytes not equal
|
|
or ch,ch ; end of string?
|
|
je equal2 ; yes, quit
|
|
shr ecx,16 ; move next pair of bytes to be tested
|
|
cmp cl,[edx+6] ; check 7th byte
|
|
jne unequal2 ; bytes not equal
|
|
or cl,cl ; end of string?
|
|
je equal2 ; yes, quit
|
|
cmp ch,[edx+7] ; check 8th byte
|
|
jne unequal2 ; bytes not equal
|
|
add eax,8 ; next 8 bytes
|
|
add edx,8 ; next 8 bytes
|
|
or ch,ch ; end of string?
|
|
_until e ; until equal
|
|
equal2:
|
|
xor eax,eax ; return 0
|
|
ifndef __STACK__
|
|
pop ecx ; restore registers
|
|
endif
|
|
ifdef _PROFILE
|
|
P5Epilog
|
|
endif
|
|
ret ; return
|
|
|
|
unequal2:
|
|
sbb eax,eax ; eax = 0 if op1>op2, -1 if op1<op2
|
|
or al,1 ; eax = 1 if op1>op2, -1 if op1<op2
|
|
ifndef __STACK__
|
|
pop ecx ; restore registers
|
|
endif
|
|
ifdef _PROFILE
|
|
P5Epilog
|
|
endif
|
|
ret ; return
|
|
endproc strcmp
|
|
|
|
endmod
|
|
end
|