1/* mc68020 __mpn_submul_1 -- Multiply a limb vector with a limb and subtract 2 * the result from a second limb vector. 3 * 4 * Copyright (C) 1992, 1994, 1996, 1998, 5 * 2001, 2002 Free Software Foundation, Inc. 6 * 7 * This file is part of Libgcrypt. 8 * 9 * Libgcrypt is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU Lesser General Public License as 11 * published by the Free Software Foundation; either version 2.1 of 12 * the License, or (at your option) any later version. 13 * 14 * Libgcrypt is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 * GNU Lesser General Public License for more details. 18 * 19 * You should have received a copy of the GNU Lesser General Public 20 * License along with this program; if not, write to the Free Software 21 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA 22 * 23 * Note: This code is heavily based on the GNU MP Library. 24 * Actually it's the same code with only minor changes in the 25 * way the data is stored; this is to support the abstraction 26 * of an optional secure memory allocation which may be used 27 * to avoid revealing of sensitive data due to paging etc. 28 */ 29 30 31 32 33#include "sysdep.h" 34#include "asm-syntax.h" 35 36/******************* 37 * mpi_limb_t 38 * _gcry_mpih_submul_1( mpi_ptr_t res_ptr, (sp + 4) 39 * mpi_ptr_t s1_ptr, (sp + 8) 40 * mpi_size_t s1_size, (sp + 12) 41 * mpi_limb_t s2_limb) (sp + 16) 42 */ 43 44 45 TEXT 46 ALIGN 47 GLOBL C_SYMBOL_NAME(_gcry_mpih_submul_1) 48 49C_SYMBOL_NAME(_gcry_mpih_submul_1:) 50PROLOG(_gcry_mpih_submul_1) 51 52#define res_ptr a0 53#define s1_ptr a1 54#define s1_size d2 55#define s2_limb d4 56 57/* Save used registers on the stack. */ 58 moveml R(d2)-R(d5),MEM_PREDEC(sp) 59 60/* Copy the arguments to registers. Better use movem? */ 61 movel MEM_DISP(sp,20),R(res_ptr) 62 movel MEM_DISP(sp,24),R(s1_ptr) 63 movel MEM_DISP(sp,28),R(s1_size) 64 movel MEM_DISP(sp,32),R(s2_limb) 65 66 eorw #1,R(s1_size) 67 clrl R(d1) 68 clrl R(d5) 69 lsrl #1,R(s1_size) 70 bcc L(L1) 71 subql #1,R(s1_size) 72 subl R(d0),R(d0) /* (d0,cy) <= (0,0) */ 73 74L(Loop:) 75 movel MEM_POSTINC(s1_ptr),R(d3) 76 mulul R(s2_limb),R(d1):R(d3) 77 addxl R(d0),R(d3) 78 addxl R(d5),R(d1) 79 subl R(d3),MEM_POSTINC(res_ptr) 80L(L1:) movel MEM_POSTINC(s1_ptr),R(d3) 81 mulul R(s2_limb),R(d0):R(d3) 82 addxl R(d1),R(d3) 83 addxl R(d5),R(d0) 84 subl R(d3),MEM_POSTINC(res_ptr) 85 86 dbf R(s1_size),L(Loop) 87 addxl R(d5),R(d0) 88 subl #0x10000,R(s1_size) 89 bcc L(Loop) 90 91/* Restore used registers from stack frame. */ 92 moveml MEM_POSTINC(sp),R(d2)-R(d5) 93 94 rts 95EPILOG(_gcry_mpih_submul_1) 96 97 98