| /* mc68020 lshift -- Shift left a low-level natural-number integer. |
| * |
| * Copyright (C) 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_lshift( mpi_ptr_t wp, (sp + 4) |
| * mpi_ptr_t up, (sp + 8) |
| * mpi_size_t usize, (sp + 12) |
| * unsigned cnt) (sp + 16) |
| */ |
| |
| #define res_ptr a1 |
| #define s_ptr a0 |
| #define s_size d6 |
| #define cnt d4 |
| |
| TEXT |
| ALIGN |
| GLOBL C_SYMBOL_NAME(_gcry_mpih_lshift) |
| |
| C_SYMBOL_NAME(_gcry_mpih_lshift:) |
| PROLOG(_gcry_mpih_lshift) |
| |
| /* Save used registers on the stack. */ |
| moveml R(d2)-R(d6)/R(a2),MEM_PREDEC(sp) |
| |
| /* Copy the arguments to registers. */ |
| movel MEM_DISP(sp,28),R(res_ptr) |
| movel MEM_DISP(sp,32),R(s_ptr) |
| movel MEM_DISP(sp,36),R(s_size) |
| movel MEM_DISP(sp,40),R(cnt) |
| |
| moveql #1,R(d5) |
| cmpl R(d5),R(cnt) |
| bne L(Lnormal) |
| cmpl R(s_ptr),R(res_ptr) |
| bls L(Lspecial) /* jump if s_ptr >= res_ptr */ |
| #if (defined (__mc68020__) || defined (__NeXT__) || defined(mc68020)) |
| lea MEM_INDX1(s_ptr,s_size,l,4),R(a2) |
| #else /* not mc68020 */ |
| movel R(s_size),R(d0) |
| asll #2,R(d0) |
| lea MEM_INDX(s_ptr,d0,l),R(a2) |
| #endif |
| cmpl R(res_ptr),R(a2) |
| bls L(Lspecial) /* jump if res_ptr >= s_ptr + s_size */ |
| |
| L(Lnormal:) |
| moveql #32,R(d5) |
| subl R(cnt),R(d5) |
| |
| #if (defined (__mc68020__) || defined (__NeXT__) || defined(mc68020)) |
| lea MEM_INDX1(s_ptr,s_size,l,4),R(s_ptr) |
| lea MEM_INDX1(res_ptr,s_size,l,4),R(res_ptr) |
| #else /* not mc68000 */ |
| movel R(s_size),R(d0) |
| asll #2,R(d0) |
| addl R(s_size),R(s_ptr) |
| addl R(s_size),R(res_ptr) |
| #endif |
| movel MEM_PREDEC(s_ptr),R(d2) |
| movel R(d2),R(d0) |
| lsrl R(d5),R(d0) /* compute carry limb */ |
| |
| lsll R(cnt),R(d2) |
| movel R(d2),R(d1) |
| subql #1,R(s_size) |
| beq L(Lend) |
| lsrl #1,R(s_size) |
| bcs L(L1) |
| subql #1,R(s_size) |
| |
| L(Loop:) |
| movel MEM_PREDEC(s_ptr),R(d2) |
| movel R(d2),R(d3) |
| lsrl R(d5),R(d3) |
| orl R(d3),R(d1) |
| movel R(d1),MEM_PREDEC(res_ptr) |
| lsll R(cnt),R(d2) |
| L(L1:) |
| movel MEM_PREDEC(s_ptr),R(d1) |
| movel R(d1),R(d3) |
| lsrl R(d5),R(d3) |
| orl R(d3),R(d2) |
| movel R(d2),MEM_PREDEC(res_ptr) |
| lsll R(cnt),R(d1) |
| |
| dbf R(s_size),L(Loop) |
| subl #0x10000,R(s_size) |
| bcc L(Loop) |
| |
| L(Lend:) |
| movel R(d1),MEM_PREDEC(res_ptr) /* store least significant limb */ |
| |
| /* Restore used registers from stack frame. */ |
| moveml MEM_POSTINC(sp),R(d2)-R(d6)/R(a2) |
| rts |
| |
| /* We loop from least significant end of the arrays, which is only |
| permissable if the source and destination don't overlap, since the |
| function is documented to work for overlapping source and destination. */ |
| |
| L(Lspecial:) |
| clrl R(d0) /* initialize carry */ |
| eorw #1,R(s_size) |
| lsrl #1,R(s_size) |
| bcc L(LL1) |
| subql #1,R(s_size) |
| |
| L(LLoop:) |
| movel MEM_POSTINC(s_ptr),R(d2) |
| addxl R(d2),R(d2) |
| movel R(d2),MEM_POSTINC(res_ptr) |
| L(LL1:) |
| movel MEM_POSTINC(s_ptr),R(d2) |
| addxl R(d2),R(d2) |
| movel R(d2),MEM_POSTINC(res_ptr) |
| |
| dbf R(s_size),L(LLoop) |
| addxl R(d0),R(d0) /* save cy in lsb */ |
| subl #0x10000,R(s_size) |
| bcs L(LLend) |
| lsrl #1,R(d0) /* restore cy */ |
| bra L(LLoop) |
| |
| L(LLend:) |
| /* Restore used registers from stack frame. */ |
| moveml MEM_POSTINC(sp),R(d2)-R(d6)/R(a2) |
| rts |
| EPILOG(_gcry_mpih_lshift) |
| |
| |
| |
| |
| |
