147 lines
3.6 KiB
ArmAsm
147 lines
3.6 KiB
ArmAsm
/* mc68020 __mpn_rshift -- Shift right a low-level natural-number integer.
|
|
|
|
Copyright (C) 1996, 1998 Free Software Foundation, Inc.
|
|
|
|
This file is part of the GNU MP Library.
|
|
|
|
The GNU MP Library is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU Library General Public License as published by
|
|
the Free Software Foundation; either version 2 of the License, or (at your
|
|
option) any later version.
|
|
|
|
The GNU MP Library 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 Library General Public
|
|
License for more details.
|
|
|
|
You should have received a copy of the GNU Library General Public License
|
|
along with the GNU MP Library; see the file COPYING.LIB. If not, write to
|
|
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
|
|
MA 02111-1307, USA. */
|
|
|
|
/*
|
|
INPUT PARAMETERS
|
|
res_ptr (sp + 4)
|
|
s_ptr (sp + 8)
|
|
s_size (sp + 16)
|
|
cnt (sp + 12)
|
|
*/
|
|
|
|
#include "sysdep.h"
|
|
#include "asm-syntax.h"
|
|
|
|
#define res_ptr a1
|
|
#define s_ptr a0
|
|
#define s_size d6
|
|
#define cnt d4
|
|
|
|
TEXT
|
|
ENTRY(__mpn_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(Lnormal)
|
|
cmpl R(res_ptr),R(s_ptr)
|
|
bls L(Lspecial) /* 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(Lspecial) /* jump if s_ptr >= res_ptr + s_size */
|
|
|
|
L(Lnormal:)
|
|
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(Lend)
|
|
lsrl #1,R(s_size)
|
|
bcs L(L1)
|
|
subql #1,R(s_size)
|
|
|
|
L(Loop:)
|
|
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(L1:)
|
|
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(Loop)
|
|
subl #0x10000,R(s_size)
|
|
bcc L(Loop)
|
|
|
|
L(Lend:)
|
|
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
|
|
permissible if the source and destination don't overlap, since the
|
|
function is documented to work for overlapping source and destination. */
|
|
|
|
L(Lspecial:)
|
|
#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(LL1)
|
|
subql #1,R(s_size)
|
|
|
|
L(LLoop:)
|
|
movel MEM_PREDEC(s_ptr),R(d2)
|
|
roxrl #1,R(d2)
|
|
movel R(d2),MEM_PREDEC(res_ptr)
|
|
L(LL1:)
|
|
movel MEM_PREDEC(s_ptr),R(d2)
|
|
roxrl #1,R(d2)
|
|
movel R(d2),MEM_PREDEC(res_ptr)
|
|
|
|
dbf R(s_size),L(LLoop)
|
|
roxrl #1,R(d0) /* save cy in msb */
|
|
subl #0x10000,R(s_size)
|
|
bcs L(LLend)
|
|
addl R(d0),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
|
|
END(__mpn_rshift)
|