mirror of
git://git.gnupg.org/gnupg.git
synced 2024-11-04 20:38:50 +01:00
165 lines
4.2 KiB
ArmAsm
165 lines
4.2 KiB
ArmAsm
|
/* mc68020 rshift -- Shift right a low-level natural-number integer.
|
||
|
|
*
|
||
|
|
* Copyright (C) 1996, 1998, 2001 Free Software Foundation, Inc.
|
||
|
|
*
|
||
|
|
* This file is part of GnuPG.
|
||
|
|
*
|
||
|
|
* GnuPG is free software; you can redistribute it and/or modify
|
||
|
|
* it under the terms of the GNU General Public License as published by
|
||
|
|
* the Free Software Foundation; either version 2 of the License, or
|
||
|
|
* (at your option) any later version.
|
||
|
|
*
|
||
|
|
* GnuPG 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 General Public License for more details.
|
||
|
|
*
|
||
|
|
* You should have received a copy of the GNU 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.
|
||
|
|
* The GNU MP Library itself is published under the LGPL;
|
||
|
|
* however I decided to publish this code under the plain GPL.
|
||
|
|
*/
|
||
|
|
|
||
|
|
|
||
|
|
#include "sysdep.h"
|
||
|
|
#include "asm-syntax.h"
|
||
|
|
|
||
|
|
|
||
|
|
/*******************
|
||
|
|
* mpi_limb_t
|
||
|
|
* mpihelp_rshift( 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(mpihelp_rshift)
|
||
|
|
|
||
|
|
C_SYMBOL_NAME(mpihelp_rshift:)
|
||
|
|
PROLOG(mpihelp_rshift)
|
||
|
|
/* 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(Rnormal)
|
||
|
|
cmpl R(res_ptr),R(s_ptr)
|
||
|
|
bls L(Rspecial) /* jump if res_ptr >= s_ptr */
|
||
|
|
#if (defined (__mc68020__) || defined (__NeXT__) || defined(mc68020))
|
||
|
|
lea MEM_INDX1(res_ptr,s_size,l,4),R(a2)
|
||
|
|
#else /* not mc68020 */
|
||
|
|
movel R(s_size),R(d0)
|
||
|
|
asll #2,R(d0)
|
||
|
|
lea MEM_INDX(res_ptr,d0,l),R(a2)
|
||
|
|
#endif
|
||
|
|
cmpl R(s_ptr),R(a2)
|
||
|
|
bls L(Rspecial) /* jump if s_ptr >= res_ptr + s_size */
|
||
|
|
|
||
|
|
L(Rnormal:)
|
||
|
|
moveql #32,R(d5)
|
||
|
|
subl R(cnt),R(d5)
|
||
|
|
movel MEM_POSTINC(s_ptr),R(d2)
|
||
|
|
movel R(d2),R(d0)
|
||
|
|
lsll R(d5),R(d0) /* compute carry limb */
|
||
|
|
|
||
|
|
lsrl R(cnt),R(d2)
|
||
|
|
movel R(d2),R(d1)
|
||
|
|
subql #1,R(s_size)
|
||
|
|
beq L(Rend)
|
||
|
|
lsrl #1,R(s_size)
|
||
|
|
bcs L(R1)
|
||
|
|
subql #1,R(s_size)
|
||
|
|
|
||
|
|
L(Roop:)
|
||
|
|
movel MEM_POSTINC(s_ptr),R(d2)
|
||
|
|
movel R(d2),R(d3)
|
||
|
|
lsll R(d5),R(d3)
|
||
|
|
orl R(d3),R(d1)
|
||
|
|
movel R(d1),MEM_POSTINC(res_ptr)
|
||
|
|
lsrl R(cnt),R(d2)
|
||
|
|
L(R1:)
|
||
|
|
movel MEM_POSTINC(s_ptr),R(d1)
|
||
|
|
movel R(d1),R(d3)
|
||
|
|
lsll R(d5),R(d3)
|
||
|
|
orl R(d3),R(d2)
|
||
|
|
movel R(d2),MEM_POSTINC(res_ptr)
|
||
|
|
lsrl R(cnt),R(d1)
|
||
|
|
|
||
|
|
dbf R(s_size),L(Roop)
|
||
|
|
subl #0x10000,R(s_size)
|
||
|
|
bcc L(Roop)
|
||
|
|
|
||
|
|
L(Rend:)
|
||
|
|
movel R(d1),MEM(res_ptr) /* store most significant limb */
|
||
|
|
|
||
|
|
/* Restore used registers from stack frame. */
|
||
|
|
moveml MEM_POSTINC(sp),R(d2)-R(d6)/R(a2)
|
||
|
|
rts
|
||
|
|
|
||
|
|
/* We loop from most 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(Rspecial:)
|
||
|
|
#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
|
||
|
|
|
||
|
|
clrl R(d0) /* initialize carry */
|
||
|
|
eorw #1,R(s_size)
|
||
|
|
lsrl #1,R(s_size)
|
||
|
|
bcc L(LR1)
|
||
|
|
subql #1,R(s_size)
|
||
|
|
|
||
|
|
L(LRoop:)
|
||
|
|
movel MEM_PREDEC(s_ptr),R(d2)
|
||
|
|
roxrl #1,R(d2)
|
||
|
|
movel R(d2),MEM_PREDEC(res_ptr)
|
||
|
|
L(LR1:)
|
||
|
|
movel MEM_PREDEC(s_ptr),R(d2)
|
||
|
|
roxrl #1,R(d2)
|
||
|
|
movel R(d2),MEM_PREDEC(res_ptr)
|
||
|
|
|
||
|
|
dbf R(s_size),L(LRoop)
|
||
|
|
roxrl #1,R(d0) /* save cy in msb */
|
||
|
|
subl #0x10000,R(s_size)
|
||
|
|
bcs L(LRend)
|
||
|
|
addl R(d0),R(d0) /* restore cy */
|
||
|
|
bra L(LRoop)
|
||
|
|
|
||
|
|
L(LRend:)
|
||
|
|
/* Restore used registers from stack frame. */
|
||
|
|
moveml MEM_POSTINC(sp),R(d2)-R(d6)/R(a2)
|
||
|
|
rts
|
||
|
|
EPILOG(mpihelp_rshift)
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|