[thirdparty/glibc.git] / ports / sysdeps / m68k / m680x0 / rshift.S

/* mc68020 __mpn_rshift -- Shift right a low-level natural-number integer.

Copyright (C) 1996-2014 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 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.

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 Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with the GNU MP Library.  If not, see <http://www.gnu.org/licenses/>.  */

/*
  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)
	cfi_adjust_cfa_offset (6*4)
	cfi_rel_offset (R(d2), 0)
	cfi_rel_offset (R(d3), 4)
	cfi_rel_offset (R(d4), 8)
	cfi_rel_offset (R(d5), 12)
	cfi_rel_offset (R(d6), 16)
	cfi_rel_offset (R(a2), 20)

/* 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)
	cfi_remember_state
	cfi_adjust_cfa_offset (-6*4)
	cfi_restore (R(d2))
	cfi_restore (R(d3))
	cfi_restore (R(d4))
	cfi_restore (R(d5))
	cfi_restore (R(d6))
	cfi_restore (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.  */

	cfi_restore_state
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)
	cfi_adjust_cfa_offset (-6*4)
	cfi_restore (R(d2))
	cfi_restore (R(d3))
	cfi_restore (R(d4))
	cfi_restore (R(d5))
	cfi_restore (R(d6))
	cfi_restore (R(a2))
	rts
END(__mpn_rshift)
Commit	Line	Data
3de9f02e RM	1	/* mc68020 __mpn_rshift -- Shift right a low-level natural-number integer.
3de9f02e RM	2
d4697bc9	3	Copyright (C) 1996-2014 Free Software Foundation, Inc.
3de9f02e RM	4
	5	This file is part of the GNU MP Library.
	6
	7	The GNU MP Library is free software; you can redistribute it and/or modify
f01ec467 AJ	8	it under the terms of the GNU Lesser General Public License as published by
f01ec467 AJ	9	the Free Software Foundation; either version 2.1 of the License, or (at your
3de9f02e RM	10	option) any later version.
	11
	12	The GNU MP Library is distributed in the hope that it will be useful, but
	13	WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
f01ec467	14	or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
3de9f02e RM	15	License for more details.
3de9f02e RM	16
f01ec467	17	You should have received a copy of the GNU Lesser General Public License
ab84e3ff	18	along with the GNU MP Library. If not, see <http://www.gnu.org/licenses/>. */
3de9f02e RM	19
	20	/*
	21	INPUT PARAMETERS
	22	res_ptr (sp + 4)
	23	s_ptr (sp + 8)
	24	s_size (sp + 16)
	25	cnt (sp + 12)
	26	*/
	27
	28	#include "sysdep.h"
	29	#include "asm-syntax.h"
	30
	31	#define res_ptr a1
	32	#define s_ptr a0
	33	#define s_size d6
	34	#define cnt d4
	35
	36	TEXT
56d7f029	37	ENTRY(__mpn_rshift)
3de9f02e RM	38	/* Save used registers on the stack. */
3de9f02e RM	39	moveml R(d2)-R(d6)/R(a2),MEM_PREDEC(sp)
50e73d13 AS	40	cfi_adjust_cfa_offset (6*4)
	41	cfi_rel_offset (R(d2), 0)
	42	cfi_rel_offset (R(d3), 4)
	43	cfi_rel_offset (R(d4), 8)
	44	cfi_rel_offset (R(d5), 12)
	45	cfi_rel_offset (R(d6), 16)
	46	cfi_rel_offset (R(a2), 20)
3de9f02e RM	47
	48	/* Copy the arguments to registers. */
	49	movel MEM_DISP(sp,28),R(res_ptr)
	50	movel MEM_DISP(sp,32),R(s_ptr)
	51	movel MEM_DISP(sp,36),R(s_size)
	52	movel MEM_DISP(sp,40),R(cnt)
	53
	54	moveql #1,R(d5)
	55	cmpl R(d5),R(cnt)
	56	bne L(Lnormal)
	57	cmpl R(res_ptr),R(s_ptr)
	58	bls L(Lspecial) /* jump if res_ptr >= s_ptr */
	59	#if (defined (__mc68020__) \|\| defined (__NeXT__) \|\| defined(mc68020))
	60	lea MEM_INDX1(res_ptr,s_size,l,4),R(a2)
	61	#else /* not mc68020 */
	62	movel R(s_size),R(d0)
	63	asll #2,R(d0)
	64	lea MEM_INDX(res_ptr,d0,l),R(a2)
	65	#endif
	66	cmpl R(s_ptr),R(a2)
	67	bls L(Lspecial) /* jump if s_ptr >= res_ptr + s_size */
	68
	69	L(Lnormal:)
	70	moveql #32,R(d5)
	71	subl R(cnt),R(d5)
	72	movel MEM_POSTINC(s_ptr),R(d2)
	73	movel R(d2),R(d0)
	74	lsll R(d5),R(d0) /* compute carry limb */
910e2e14	75
3de9f02e RM	76	lsrl R(cnt),R(d2)
	77	movel R(d2),R(d1)
	78	subql #1,R(s_size)
	79	beq L(Lend)
	80	lsrl #1,R(s_size)
	81	bcs L(L1)
	82	subql #1,R(s_size)
	83
	84	L(Loop:)
	85	movel MEM_POSTINC(s_ptr),R(d2)
	86	movel R(d2),R(d3)
	87	lsll R(d5),R(d3)
	88	orl R(d3),R(d1)
	89	movel R(d1),MEM_POSTINC(res_ptr)
	90	lsrl R(cnt),R(d2)
	91	L(L1:)
	92	movel MEM_POSTINC(s_ptr),R(d1)
	93	movel R(d1),R(d3)
	94	lsll R(d5),R(d3)
	95	orl R(d3),R(d2)
	96	movel R(d2),MEM_POSTINC(res_ptr)
	97	lsrl R(cnt),R(d1)
	98
	99	dbf R(s_size),L(Loop)
	100	subl #0x10000,R(s_size)
	101	bcc L(Loop)
	102
	103	L(Lend:)
	104	movel R(d1),MEM(res_ptr) /* store most significant limb */
	105
	106	/* Restore used registers from stack frame. */
	107	moveml MEM_POSTINC(sp),R(d2)-R(d6)/R(a2)
50e73d13 AS	108	cfi_remember_state
	109	cfi_adjust_cfa_offset (-6*4)
	110	cfi_restore (R(d2))
	111	cfi_restore (R(d3))
	112	cfi_restore (R(d4))
	113	cfi_restore (R(d5))
	114	cfi_restore (R(d6))
	115	cfi_restore (R(a2))
3de9f02e RM	116	rts
	117
	118	/* We loop from most significant end of the arrays, which is only
910e2e14	119	permissible if the source and destination don't overlap, since the
3de9f02e RM	120	function is documented to work for overlapping source and destination. */
3de9f02e RM	121
50e73d13	122	cfi_restore_state
3de9f02e RM	123	L(Lspecial:)
	124	#if (defined (__mc68020__) \|\| defined (__NeXT__) \|\| defined(mc68020))
	125	lea MEM_INDX1(s_ptr,s_size,l,4),R(s_ptr)
	126	lea MEM_INDX1(res_ptr,s_size,l,4),R(res_ptr)
	127	#else /* not mc68000 */
	128	movel R(s_size),R(d0)
	129	asll #2,R(d0)
	130	addl R(s_size),R(s_ptr)
	131	addl R(s_size),R(res_ptr)
	132	#endif
	133
	134	clrl R(d0) /* initialize carry */
	135	eorw #1,R(s_size)
	136	lsrl #1,R(s_size)
	137	bcc L(LL1)
	138	subql #1,R(s_size)
	139
	140	L(LLoop:)
	141	movel MEM_PREDEC(s_ptr),R(d2)
	142	roxrl #1,R(d2)
	143	movel R(d2),MEM_PREDEC(res_ptr)
	144	L(LL1:)
	145	movel MEM_PREDEC(s_ptr),R(d2)
	146	roxrl #1,R(d2)
	147	movel R(d2),MEM_PREDEC(res_ptr)
	148
	149	dbf R(s_size),L(LLoop)
	150	roxrl #1,R(d0) /* save cy in msb */
	151	subl #0x10000,R(s_size)
	152	bcs L(LLend)
	153	addl R(d0),R(d0) /* restore cy */
	154	bra L(LLoop)
	155
	156	L(LLend:)
	157	/* Restore used registers from stack frame. */
	158	moveml MEM_POSTINC(sp),R(d2)-R(d6)/R(a2)
50e73d13 AS	159	cfi_adjust_cfa_offset (-6*4)
	160	cfi_restore (R(d2))
	161	cfi_restore (R(d3))
	162	cfi_restore (R(d4))
	163	cfi_restore (R(d5))
	164	cfi_restore (R(d6))
	165	cfi_restore (R(a2))
3de9f02e	166	rts
56d7f029	167	END(__mpn_rshift)