| /* 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, |
| * 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_sub_n( mpi_ptr_t res_ptr, (sp + 4) |
| * mpi_ptr_t s1_ptr, (sp + 8) |
| * mpi_ptr_t s2_ptr, (sp + 16) |
| * mpi_size_t size) (sp + 12) |
| */ |
| |
| |
| TEXT |
| ALIGN |
| GLOBL C_SYMBOL_NAME(_gcry_mpih_sub_n) |
| |
| C_SYMBOL_NAME(_gcry_mpih_sub_n:) |
| PROLOG(_gcry_mpih_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 |
| EPILOG(_gcry_mpih_sub_n) |
| |
| |
