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/* mc68020 __mpn_sub_n -- Subtract two limb vectors of the same length > 0 and
store difference in a third limb vector.
Copyright (C) 1992, 1994, 1996, 1998 Free Software Foundation, Inc.
This file is part of the GNU MP Library.
The GNU MP 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; either version 2 of the License, or (at your
option) any later version.
The GNU MP 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 the GNU MP Library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA. */
/*
INPUT PARAMETERS
res_ptr (sp + 4)
s1_ptr (sp + 8)
s2_ptr (sp + 16)
size (sp + 12)
*/
#include "sysdep.h"
#include "asm-syntax.h"
TEXT
ENTRY(__mpn_sub_n)
/* Save used registers on the stack. */
movel R(d2),MEM_PREDEC(sp)
movel R(a2),MEM_PREDEC(sp)
/* Copy the arguments to registers. Better use movem? */
movel MEM_DISP(sp,12),R(a2)
movel MEM_DISP(sp,16),R(a0)
movel MEM_DISP(sp,20),R(a1)
movel MEM_DISP(sp,24),R(d2)
eorw #1,R(d2)
lsrl #1,R(d2)
bcc L(L1)
subql #1,R(d2) /* clears cy as side effect */
L(Loop:)
movel MEM_POSTINC(a0),R(d0)
movel MEM_POSTINC(a1),R(d1)
subxl R(d1),R(d0)
movel R(d0),MEM_POSTINC(a2)
L(L1:) movel MEM_POSTINC(a0),R(d0)
movel MEM_POSTINC(a1),R(d1)
subxl R(d1),R(d0)
movel R(d0),MEM_POSTINC(a2)
dbf R(d2),L(Loop) /* loop until 16 lsb of %4 == -1 */
subxl R(d0),R(d0) /* d0 <= -cy; save cy as 0 or -1 in d0 */
subl #0x10000,R(d2)
bcs L(L2)
addl R(d0),R(d0) /* restore cy */
bra L(Loop)
L(L2:)
negl R(d0)
/* Restore used registers from stack frame. */
movel MEM_POSTINC(sp),R(a2)
movel MEM_POSTINC(sp),R(d2)
rts
END(__mpn_sub_n)
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