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; Copyright (c) 2000, 2006 MySQL AB
;
; This library is free software; you can redistribute it and/or
; modify it under the terms of the GNU Library General Public
; License as published by the Free Software Foundation; version 2
; of the License.
;
; This library 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
; Library General Public License for more details.
;
; You should have received a copy of the GNU Library General Public
; License along with this library; if not, write to the Free
; Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
; MA 02110-1301, USA
TITLE Optimized cmp of pointer to strings of unsigned chars
ifndef M_I386
.8087
DOSSEG
.MODEL LARGE
.DATA
compare_length dw 0
.CODE STRINGS
PUBLIC _get_ptr_compare
_get_ptr_compare PROC
mov bx,sp
mov cx,ss:[BX+4]
mov compare_length,cx
mov dx,seg strings:_ptr_cmp
mov ax,offset _ptr_cmp_0
jcxz @F
mov ax,offset _ptr_cmp_1
dec cx
jz @F
mov ax,offset _ptr_cmp
@@: ret
_get_ptr_compare ENDP
_ptr_cmp_0 PROC
mov AX,0 ; Emptyt strings are always equal
ret
_ptr_cmp_0 ENDP
_ptr_cmp_1 PROC
mov bx,sp
mov dx,si ; Save si and ds
mov cx,ds
lds si,DWORD PTR ss:[bx+4] ; s1
lds si,DWORD PTR ds:[si]
mov al,ds:[si]
xor ah,ah
lds si,DWORD PTR ss:[bx+8] ; s2
lds si,DWORD PTR ds:[si]
mov bl,ds:[si]
mov bh,ah
sub ax,bx
mov ds,cx ; restore si and ds
mov si,dx
ret
_ptr_cmp_1 ENDP
_ptr_cmp PROC
mov bx,bp ; Save bp
mov dx,di ; Save di
mov bp,sp
push ds
push si
mov cx,compare_length ; Length of memory-area
lds si,DWORD PTR [bp+4] ; s1
lds si,DWORD PTR ds:[si]
les di,DWORD PTR [bp+8] ; s2
les di,DWORD PTR es:[di]
; cld ; Work uppward
xor ax,ax
repe cmpsb ; Compare strings
je @F ; Strings are equal
sbb ax,ax
cmc
adc ax,0
@@: pop si
pop ds
mov di,dx
mov bp,bx
ret
_ptr_cmp ENDP
else
include macros.asm
fix_es MACRO fix_cld ; Load ES if neaded
ife ESeqDS
mov ax,ds
mov es,ax
endif
ifnb <fix_cld>
cld
endif
ENDM
begdata
compare_length dd 0 ; Length of strings
enddata
begcode get_ptr_compare
public _get_ptr_compare
_get_ptr_compare proc near
mov ecx,P-SIZEPTR[esp]
mov compare_length,ecx
mov eax,offset _TEXT:_ptr_cmp_0
jecxz @F
mov eax,offset _TEXT:_ptr_cmp_1
dec ecx
jz @F
mov eax,offset _TEXT:_ptr_cmp
@@: ret
_get_ptr_compare endp
endcode _get_ptr_compare
begcode ptr_cmp_0
_ptr_cmp_0 PROC
mov EAX,0 ; Emptyt strings are always equal
ret
_ptr_cmp_0 ENDP
endcode ptr_cmp_0
begcode ptr_cmp_1
_ptr_cmp_1 proc near
mov edx,esi ; Save esi
mov esi,P-SIZEPTR[esp] ; *s1
mov esi,[esi]
movzx eax,[esi]
mov esi,P[esp] ; *s2
mov esi,[esi]
movzx ecx,[esi]
sub eax,ecx
mov esi,edx ; Restore esi
ret
_ptr_cmp_1 ENDP
endcode ptr_cmp_1
begcode ptr_cmp
_ptr_cmp proc near
fix_es 1
push ebp
mov ebp,esp
mov edx,edi ; Save esi
push esi
mov esi,P[ebp] ; *s1
mov esi,[esi]
mov edi,P+SIZEPTR[ebp] ; *s2
mov edi,[edi]
mov ecx,compare_length ; Length of memory-area
xor eax,eax
repe cmpsb ; Compare strings
je @F ; Strings are equal
sbb eax,eax
cmc
adc eax,0
@@: pop esi
mov edi,edx
pop ebp
ret
_ptr_cmp ENDP
endcode ptr_cmp
endif
END
|
