/* mc68020 __mpn_submul_1 -- Multiply a limb vector with a limb and subtract
* the result from a second limb vector.
*
* Copyright (C) 1992, 1994, 1996, 1998,
* 2001, 2002 Free Software Foundation, Inc.
*
* This file is part of Libgcrypt.
*
* Libgcrypt is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* Libgcrypt 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser 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
*
* Note: This code is heavily based on the GNU MP Library.
* Actually it's the same code with only minor changes in the
* way the data is stored; this is to support the abstraction
* of an optional secure memory allocation which may be used
* to avoid revealing of sensitive data due to paging etc.
*/
#include "sysdep.h"
#include "asm-syntax.h"
/*******************
* mpi_limb_t
* _gcry_mpih_submul_1( mpi_ptr_t res_ptr, (sp + 4)
* mpi_ptr_t s1_ptr, (sp + 8)
* mpi_size_t s1_size, (sp + 12)
* mpi_limb_t s2_limb) (sp + 16)
*/
TEXT
ALIGN
GLOBL C_SYMBOL_NAME(_gcry_mpih_submul_1)
C_SYMBOL_NAME(_gcry_mpih_submul_1:)
PROLOG(_gcry_mpih_submul_1)
#define res_ptr a0
#define s1_ptr a1
#define s1_size d2
#define s2_limb d4
/* Save used registers on the stack. */
moveml R(d2)-R(d5),MEM_PREDEC(sp)
/* Copy the arguments to registers. Better use movem? */
movel MEM_DISP(sp,20),R(res_ptr)
movel MEM_DISP(sp,24),R(s1_ptr)
movel MEM_DISP(sp,28),R(s1_size)
movel MEM_DISP(sp,32),R(s2_limb)
eorw #1,R(s1_size)
clrl R(d1)
clrl R(d5)
lsrl #1,R(s1_size)
bcc L(L1)
subql #1,R(s1_size)
subl R(d0),R(d0) /* (d0,cy) <= (0,0) */
L(Loop:)
movel MEM_POSTINC(s1_ptr),R(d3)
mulul R(s2_limb),R(d1):R(d3)
addxl R(d0),R(d3)
addxl R(d5),R(d1)
subl R(d3),MEM_POSTINC(res_ptr)
L(L1:) movel MEM_POSTINC(s1_ptr),R(d3)
mulul R(s2_limb),R(d0):R(d3)
addxl R(d1),R(d3)
addxl R(d5),R(d0)
subl R(d3),MEM_POSTINC(res_ptr)
dbf R(s1_size),L(Loop)
addxl R(d5),R(d0)
subl #0x10000,R(s1_size)
bcc L(Loop)
/* Restore used registers from stack frame. */
moveml MEM_POSTINC(sp),R(d2)-R(d5)
rts
EPILOG(_gcry_mpih_submul_1)
