[thirdparty/gcc.git] / libgcc / config / cris / mulsi3.S

;; Copyright (C) 2001-2021 Free Software Foundation, Inc.
;;
;; This file is part of GCC.
;;
;; GCC 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 3, or (at your option) any later
;; version.
;;
;; GCC 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.
;;
;; Under Section 7 of GPL version 3, you are granted additional
;; permissions described in the GCC Runtime Library Exception, version
;; 3.1, as published by the Free Software Foundation.
;;
;; You should have received a copy of the GNU General Public License and
;; a copy of the GCC Runtime Library Exception along with this program;
;; see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
;; <http://www.gnu.org/licenses/>.
;;
;; This code used to be expanded through interesting expansions in
;; the machine description, compiled from this code:
;;
;; #ifdef L_mulsi3
;; long __Mul (unsigned long a, unsigned long b) __attribute__ ((__const__));
;; 
;; /* This must be compiled with the -mexpand-mul flag, to synthesize the
;;    multiplication from the mstep instructions.  The check for
;;    smaller-size multiplication pays off in the order of .5-10%;
;;    estimated median 1%, depending on application.
;;     FIXME: It can be further optimized if we go to assembler code, as
;;    gcc 2.7.2 adds a few unnecessary instructions and does not put the
;;    basic blocks in optimal order.  */
;; long
;; __Mul (unsigned long a, unsigned long b)
;; {
;; #if defined (__CRIS_arch_version) && __CRIS_arch_version >= 10
;;   /* In case other code is compiled without -march=v10, they will
;; 	contain calls to __Mul, regardless of flags at link-time.  The
;; 	"else"-code below will work, but is unnecessarily slow.  This
;; 	sometimes cuts a few minutes off from simulation time by just
;; 	returning a "mulu.d".  */
;;   return a * b;
;; #else
;;   unsigned long min;
;; 
;;   /* Get minimum via the bound insn.  */
;;   min = a < b ? a : b;
;; 
;;   /* Can we omit computation of the high part?	*/
;;   if (min > 65535)
;;     /* No.  Perform full multiplication.  */
;;     return a * b;
;;   else
;;     {
;; 	 /* Check if both operands are within 16 bits.  */
;; 	 unsigned long max;
;; 
;; 	 /* Get maximum, by knowing the minimum.
;; 	    This will partition a and b into max and min.
;; 	    This is not currently something GCC understands,
;; 	    so do this trick by asm.  */
;; 	 __asm__ ("xor %1,%0\n\txor %2,%0"
;; 		  : "=r" (max)
;; 		  :  "r" (b), "r" (a), "0" (min));
;; 
;;     if (max > 65535)
;; 	 /* Make GCC understand that only the low part of "min" will be
;; 	    used.  */
;; 	 return max * (unsigned short) min;
;;     else
;; 	 /* Only the low parts of both operands are necessary.  */
;; 	 return ((unsigned short) max) * (unsigned short) min;
;;     }
;; #endif /* not __CRIS_arch_version >= 10 */
;; }
;; #endif /* L_mulsi3 */
;;
;; That approach was abandoned since the caveats outweighted the
;; benefits.  The expand-multiplication machinery is also removed, so you
;; can't do this anymore.
;;
;; For doubters of there being any benefits, some where: insensitivity to:
;; - ABI changes (mostly for experimentation)
;; - assembler syntax differences (mostly debug format).
;; - insn scheduling issues.
;; Most ABI experiments will presumably happen with arches with mul insns,
;; so that argument doesn't really hold anymore, and it's unlikely there
;; being new arch variants needing insn scheduling and not having mul
;; insns.

;; ELF and a.out have different syntax for local labels: the "wrong"
;; one may not be omitted from the object.
#undef L
#ifdef __AOUT__
# define L(x) x
#else
# define L(x) .x
#endif

	.global ___Mul
	.type	___Mul,@function
___Mul:
#if defined (__CRIS_arch_version) && __CRIS_arch_version >= 10
;; Can't have the mulu.d last on a cache-line (in the delay-slot of the
;; "ret"), due to hardware bug.  See documentation for -mmul-bug-workaround.
;; Not worthwhile to conditionalize here.
	.p2alignw 2,0x050f
	mulu.d $r11,$r10
	ret
	nop
#else
;; See if we can avoid multiplying some of the parts, knowing
;; they're zero.

	move.d $r11,$r9
	bound.d $r10,$r9
	cmpu.w 65535,$r9
	bls L(L3)
	move.d $r10,$r12

;; Nope, have to do all the parts of a 32-bit multiplication.
;; See head comment in optabs.c:expand_doubleword_mult.

	move.d $r10,$r13
	movu.w $r11,$r9 ; ab*cd = (a*d + b*c)<<16 + b*d
	lslq 16,$r13
	mstep $r9,$r13	; d*b
	mstep $r9,$r13
	mstep $r9,$r13
	mstep $r9,$r13
	mstep $r9,$r13
	mstep $r9,$r13
	mstep $r9,$r13
	mstep $r9,$r13
	mstep $r9,$r13
	mstep $r9,$r13
	mstep $r9,$r13
	mstep $r9,$r13
	mstep $r9,$r13
	mstep $r9,$r13
	mstep $r9,$r13
	mstep $r9,$r13
	clear.w $r10
	test.d $r10
	mstep $r9,$r10	; d*a
	mstep $r9,$r10
	mstep $r9,$r10
	mstep $r9,$r10
	mstep $r9,$r10
	mstep $r9,$r10
	mstep $r9,$r10
	mstep $r9,$r10
	mstep $r9,$r10
	mstep $r9,$r10
	mstep $r9,$r10
	mstep $r9,$r10
	mstep $r9,$r10
	mstep $r9,$r10
	mstep $r9,$r10
	mstep $r9,$r10
	movu.w $r12,$r12
	clear.w $r11
	move.d $r11,$r9 ; Doubles as a "test.d" preparing for the mstep.
	mstep $r12,$r9	; b*c
	mstep $r12,$r9
	mstep $r12,$r9
	mstep $r12,$r9
	mstep $r12,$r9
	mstep $r12,$r9
	mstep $r12,$r9
	mstep $r12,$r9
	mstep $r12,$r9
	mstep $r12,$r9
	mstep $r12,$r9
	mstep $r12,$r9
	mstep $r12,$r9
	mstep $r12,$r9
	mstep $r12,$r9
	mstep $r12,$r9
	add.w $r9,$r10
	lslq 16,$r10
	ret
	add.d $r13,$r10

L(L3):
;; Form the maximum in $r10, by knowing the minimum, $r9.
;; (We don't know which one of $r10 or $r11 it is.)
;; Check if the largest operand is still just 16 bits.

	xor $r9,$r10
	xor $r11,$r10
	cmpu.w 65535,$r10
	bls L(L5)
	movu.w $r9,$r13

;; We have ab*cd = (a*c)<<32 + (a*d + b*c)<<16 + b*d, but c==0
;; so we only need (a*d)<<16 + b*d with d = $r13, ab = $r10.
;; We drop the upper part of (a*d)<<16 as we're only doing a
;; 32-bit-result multiplication.

	move.d $r10,$r9
	lslq 16,$r9
	mstep $r13,$r9	; b*d
	mstep $r13,$r9
	mstep $r13,$r9
	mstep $r13,$r9
	mstep $r13,$r9
	mstep $r13,$r9
	mstep $r13,$r9
	mstep $r13,$r9
	mstep $r13,$r9
	mstep $r13,$r9
	mstep $r13,$r9
	mstep $r13,$r9
	mstep $r13,$r9
	mstep $r13,$r9
	mstep $r13,$r9
	mstep $r13,$r9
	clear.w $r10
	test.d $r10
	mstep $r13,$r10	; a*d
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	lslq 16,$r10
	ret
	add.d $r9,$r10

L(L5):
;; We have ab*cd = (a*c)<<32 + (a*d + b*c)<<16 + b*d, but a and c==0
;; so b*d (with b=$r13, a=$r10) it is.

	lslq 16,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	mstep $r13,$r10
	ret
	mstep $r13,$r10
#endif
L(Lfe1):
	.size	___Mul,L(Lfe1)-___Mul
Commit	Line	Data
99dee823	1	;; Copyright (C) 2001-2021 Free Software Foundation, Inc.
ad41bd84 JM	2	;;
	3	;; This file is part of GCC.
	4	;;
	5	;; GCC is free software; you can redistribute it and/or modify it under
	6	;; the terms of the GNU General Public License as published by the Free
	7	;; Software Foundation; either version 3, or (at your option) any later
	8	;; version.
	9	;;
	10	;; GCC is distributed in the hope that it will be useful, but WITHOUT ANY
	11	;; WARRANTY; without even the implied warranty of MERCHANTABILITY or
	12	;; FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	13	;; for more details.
	14	;;
	15	;; Under Section 7 of GPL version 3, you are granted additional
	16	;; permissions described in the GCC Runtime Library Exception, version
	17	;; 3.1, as published by the Free Software Foundation.
	18	;;
	19	;; You should have received a copy of the GNU General Public License and
	20	;; a copy of the GCC Runtime Library Exception along with this program;
	21	;; see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
	22	;; <http://www.gnu.org/licenses/>.
	23	;;
0b85d816 HPN	24	;; This code used to be expanded through interesting expansions in
	25	;; the machine description, compiled from this code:
	26	;;
	27	;; #ifdef L_mulsi3
	28	;; long __Mul (unsigned long a, unsigned long b) __attribute__ ((__const__));
	29	;;
	30	;; /* This must be compiled with the -mexpand-mul flag, to synthesize the
	31	;; multiplication from the mstep instructions. The check for
	32	;; smaller-size multiplication pays off in the order of .5-10%;
	33	;; estimated median 1%, depending on application.
	34	;; FIXME: It can be further optimized if we go to assembler code, as
	35	;; gcc 2.7.2 adds a few unnecessary instructions and does not put the
	36	;; basic blocks in optimal order. */
	37	;; long
	38	;; __Mul (unsigned long a, unsigned long b)
	39	;; {
	40	;; #if defined (__CRIS_arch_version) && __CRIS_arch_version >= 10
	41	;; /* In case other code is compiled without -march=v10, they will
	42	;; contain calls to __Mul, regardless of flags at link-time. The
	43	;; "else"-code below will work, but is unnecessarily slow. This
	44	;; sometimes cuts a few minutes off from simulation time by just
	45	;; returning a "mulu.d". */
	46	;; return a * b;
	47	;; #else
	48	;; unsigned long min;
	49	;;
	50	;; /* Get minimum via the bound insn. */
	51	;; min = a < b ? a : b;
	52	;;
	53	;; /* Can we omit computation of the high part? */
	54	;; if (min > 65535)
	55	;; /* No. Perform full multiplication. */
	56	;; return a * b;
	57	;; else
	58	;; {
	59	;; /* Check if both operands are within 16 bits. */
	60	;; unsigned long max;
	61	;;
	62	;; /* Get maximum, by knowing the minimum.
	63	;; This will partition a and b into max and min.
	64	;; This is not currently something GCC understands,
	65	;; so do this trick by asm. */
	66	;; __asm__ ("xor %1,%0\n\txor %2,%0"
	67	;; : "=r" (max)
	68	;; : "r" (b), "r" (a), "0" (min));
	69	;;
	70	;; if (max > 65535)
	71	;; /* Make GCC understand that only the low part of "min" will be
	72	;; used. */
	73	;; return max * (unsigned short) min;
	74	;; else
	75	;; /* Only the low parts of both operands are necessary. */
	76	;; return ((unsigned short) max) * (unsigned short) min;
	77	;; }
	78	;; #endif /* not __CRIS_arch_version >= 10 */
	79	;; }
	80	;; #endif /* L_mulsi3 */
	81	;;
	82	;; That approach was abandoned since the caveats outweighted the
	83	;; benefits. The expand-multiplication machinery is also removed, so you
	84	;; can't do this anymore.
	85	;;
	86	;; For doubters of there being any benefits, some where: insensitivity to:
	87	;; - ABI changes (mostly for experimentation)
88	;; - assembler syntax differences (mostly debug format).
89	;; - insn scheduling issues.
90	;; Most ABI experiments will presumably happen with arches with mul insns,
91	;; so that argument doesn't really hold anymore, and it's unlikely there
92	;; being new arch variants needing insn scheduling and not having mul
93	;; insns.
94
95	;; ELF and a.out have different syntax for local labels: the "wrong"
96	;; one may not be omitted from the object.
97	#undef L
98	#ifdef __AOUT__
99	# define L(x) x
100	#else
101	# define L(x) .x
102	#endif
103
104	.global ___Mul
105	.type ___Mul,@function
106	___Mul:
107	#if defined (__CRIS_arch_version) && __CRIS_arch_version >= 10
86da66b5 HPN	108	;; Can't have the mulu.d last on a cache-line (in the delay-slot of the
	109	;; "ret"), due to hardware bug. See documentation for -mmul-bug-workaround.
	110	;; Not worthwhile to conditionalize here.
	111	.p2alignw 2,0x050f
0b85d816	112	mulu.d $r11,$r10
86da66b5 HPN	113	ret
86da66b5 HPN	114	nop
0b85d816	115	#else
0e499e75 HPN	116	;; See if we can avoid multiplying some of the parts, knowing
	117	;; they're zero.
	118
0b85d816	119	move.d $r11,$r9
0e499e75	120	bound.d $r10,$r9
0b85d816 HPN	121	cmpu.w 65535,$r9
0b85d816 HPN	122	bls L(L3)
0e499e75	123	move.d $r10,$r12
0b85d816	124
0e499e75 HPN	125	;; Nope, have to do all the parts of a 32-bit multiplication.
	126	;; See head comment in optabs.c:expand_doubleword_mult.
	127
	128	move.d $r10,$r13
	129	movu.w $r11,$r9 ; abcd = (ad + bc)<<16 + bd
0b85d816	130	lslq 16,$r13
0e499e75	131	mstep $r9,$r13 ; d*b
0b85d816 HPN	132	mstep $r9,$r13
	133	mstep $r9,$r13
	134	mstep $r9,$r13
	135	mstep $r9,$r13
	136	mstep $r9,$r13
	137	mstep $r9,$r13
	138	mstep $r9,$r13
	139	mstep $r9,$r13
	140	mstep $r9,$r13
	141	mstep $r9,$r13
	142	mstep $r9,$r13
	143	mstep $r9,$r13
	144	mstep $r9,$r13
	145	mstep $r9,$r13
	146	mstep $r9,$r13
	147	clear.w $r10
	148	test.d $r10
0e499e75	149	mstep $r9,$r10 ; d*a
0b85d816 HPN	150	mstep $r9,$r10
	151	mstep $r9,$r10
	152	mstep $r9,$r10
	153	mstep $r9,$r10
	154	mstep $r9,$r10
	155	mstep $r9,$r10
	156	mstep $r9,$r10
	157	mstep $r9,$r10
	158	mstep $r9,$r10
	159	mstep $r9,$r10
	160	mstep $r9,$r10
	161	mstep $r9,$r10
	162	mstep $r9,$r10
	163	mstep $r9,$r10
	164	mstep $r9,$r10
	165	movu.w $r12,$r12
0e499e75 HPN	166	clear.w $r11
	167	move.d $r11,$r9 ; Doubles as a "test.d" preparing for the mstep.
	168	mstep $r12,$r9 ; b*c
0b85d816 HPN	169	mstep $r12,$r9
	170	mstep $r12,$r9
	171	mstep $r12,$r9
	172	mstep $r12,$r9
	173	mstep $r12,$r9
	174	mstep $r12,$r9
	175	mstep $r12,$r9
	176	mstep $r12,$r9
	177	mstep $r12,$r9
	178	mstep $r12,$r9
	179	mstep $r12,$r9
	180	mstep $r12,$r9
	181	mstep $r12,$r9
	182	mstep $r12,$r9
	183	mstep $r12,$r9
	184	add.w $r9,$r10
	185	lslq 16,$r10
	186	ret
	187	add.d $r13,$r10
	188
	189	L(L3):
0e499e75 HPN	190	;; Form the maximum in $r10, by knowing the minimum, $r9.
	191	;; (We don't know which one of $r10 or $r11 it is.)
	192	;; Check if the largest operand is still just 16 bits.
	193
	194	xor $r9,$r10
0b85d816	195	xor $r11,$r10
0b85d816 HPN	196	cmpu.w 65535,$r10
	197	bls L(L5)
	198	movu.w $r9,$r13
	199
0e499e75 HPN	200	;; We have abcd = (ac)<<32 + (ad + bc)<<16 + b*d, but c==0
	201	;; so we only need (ad)<<16 + bd with d = $r13, ab = $r10.
	202	;; We drop the upper part of (a*d)<<16 as we're only doing a
	203	;; 32-bit-result multiplication.
	204
0b85d816 HPN	205	move.d $r10,$r9
0b85d816 HPN	206	lslq 16,$r9
0e499e75	207	mstep $r13,$r9 ; b*d
0b85d816 HPN	208	mstep $r13,$r9
	209	mstep $r13,$r9
	210	mstep $r13,$r9
	211	mstep $r13,$r9
	212	mstep $r13,$r9
	213	mstep $r13,$r9
	214	mstep $r13,$r9
	215	mstep $r13,$r9
	216	mstep $r13,$r9
	217	mstep $r13,$r9
	218	mstep $r13,$r9
	219	mstep $r13,$r9
	220	mstep $r13,$r9
	221	mstep $r13,$r9
	222	mstep $r13,$r9
	223	clear.w $r10
	224	test.d $r10
0e499e75	225	mstep $r13,$r10 ; a*d
0b85d816 HPN	226	mstep $r13,$r10
	227	mstep $r13,$r10
	228	mstep $r13,$r10
	229	mstep $r13,$r10
	230	mstep $r13,$r10
	231	mstep $r13,$r10
	232	mstep $r13,$r10
	233	mstep $r13,$r10
	234	mstep $r13,$r10
	235	mstep $r13,$r10
	236	mstep $r13,$r10
	237	mstep $r13,$r10
	238	mstep $r13,$r10
	239	mstep $r13,$r10
	240	mstep $r13,$r10
	241	lslq 16,$r10
	242	ret
	243	add.d $r9,$r10
	244
	245	L(L5):
0e499e75 HPN	246	;; We have abcd = (ac)<<32 + (ad + bc)<<16 + b*d, but a and c==0
	247	;; so b*d (with b=$r13, a=$r10) it is.
	248
0b85d816	249	lslq 16,$r10
0e499e75 HPN	250	mstep $r13,$r10
	251	mstep $r13,$r10
	252	mstep $r13,$r10
	253	mstep $r13,$r10
	254	mstep $r13,$r10
	255	mstep $r13,$r10
	256	mstep $r13,$r10
	257	mstep $r13,$r10
	258	mstep $r13,$r10
	259	mstep $r13,$r10
	260	mstep $r13,$r10
	261	mstep $r13,$r10
	262	mstep $r13,$r10
	263	mstep $r13,$r10
	264	mstep $r13,$r10
0b85d816	265	ret
0e499e75	266	mstep $r13,$r10
0b85d816 HPN	267	#endif
	268	L(Lfe1):
	269	.size ___Mul,L(Lfe1)-___Mul