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 Free Software Foundation, Inc. 6 * 7 * This file is part of GnuPG. 8 * 9 * GnuPG is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License as published by 11 * the Free Software Foundation; either version 3 of the License, or 12 * (at your option) any later version. 13 * 14 * GnuPG 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 General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License 20 * along with this program; if not, see <http://www.gnu.org/licenses/>. 21 * 22 * Note: This code is heavily based on the GNU MP Library. 23 * Actually it's the same code with only minor changes in the 24 * way the data is stored; this is to support the abstraction 25 * of an optional secure memory allocation which may be used 26 * to avoid revealing of sensitive data due to paging etc. 27 * The GNU MP Library itself is published under the LGPL; 28 * however I decided to publish this code under the plain GPL. 29 */ 30 31 32 33 34#include "sysdep.h" 35#include "asm-syntax.h" 36 37/******************* 38 * mpi_limb_t 39 * mpihelp_submul_1( mpi_ptr_t res_ptr, (sp + 4) 40 * mpi_ptr_t s1_ptr, (sp + 8) 41 * mpi_size_t s1_size, (sp + 12) 42 * mpi_limb_t s2_limb) (sp + 16) 43 */ 44 45 46 TEXT 47 ALIGN 48 GLOBL C_SYMBOL_NAME(mpihelp_submul_1) 49 50C_SYMBOL_NAME(mpihelp_submul_1:) 51PROLOG(mpihelp_submul_1) 52 53#define res_ptr a0 54#define s1_ptr a1 55#define s1_size d2 56#define s2_limb d4 57 58/* Save used registers on the stack. */ 59 moveml R(d2)-R(d5),MEM_PREDEC(sp) 60 61/* Copy the arguments to registers. Better use movem? */ 62 movel MEM_DISP(sp,20),R(res_ptr) 63 movel MEM_DISP(sp,24),R(s1_ptr) 64 movel MEM_DISP(sp,28),R(s1_size) 65 movel MEM_DISP(sp,32),R(s2_limb) 66 67 eorw #1,R(s1_size) 68 clrl R(d1) 69 clrl R(d5) 70 lsrl #1,R(s1_size) 71 bcc L(L1) 72 subql #1,R(s1_size) 73 subl R(d0),R(d0) /* (d0,cy) <= (0,0) */ 74 75L(Loop:) 76 movel MEM_POSTINC(s1_ptr),R(d3) 77 mulul R(s2_limb),R(d1):R(d3) 78 addxl R(d0),R(d3) 79 addxl R(d5),R(d1) 80 subl R(d3),MEM_POSTINC(res_ptr) 81L(L1:) movel MEM_POSTINC(s1_ptr),R(d3) 82 mulul R(s2_limb),R(d0):R(d3) 83 addxl R(d1),R(d3) 84 addxl R(d5),R(d0) 85 subl R(d3),MEM_POSTINC(res_ptr) 86 87 dbf R(s1_size),L(Loop) 88 addxl R(d5),R(d0) 89 subl #0x10000,R(s1_size) 90 bcc L(Loop) 91 92/* Restore used registers from stack frame. */ 93 moveml MEM_POSTINC(sp),R(d2)-R(d5) 94 95 rts 96EPILOG(mpihelp_submul_1) 97 98 99