From: Richard Henderson <rth@twiddle.net>
To: libc-ports@sourceware.org
Cc: joseph@codesourcery.com
Subject: [PATCH v2 13/14] arm: Add optimized submul_1
Date: Fri, 01 Mar 2013 17:36:00 -0000 [thread overview]
Message-ID: <1362159320-5934-14-git-send-email-rth@twiddle.net> (raw)
In-Reply-To: <1362159320-5934-1-git-send-email-rth@twiddle.net>
Written from scratch rather than copied from GMP, due to GPL 2.1 vs
GPL 3, but tested with the GMP testsuite.
This is 50% faster than the generic code as measured on Cortex-A15,
and the same speed as GMP on the same core. It's probably slower
than GMP on the A8 and A9 cores though.
---
* sysdeps/arm/submul_1.S: New file.
---
ports/sysdeps/arm/submul_1.S | 67 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 67 insertions(+)
create mode 100644 ports/sysdeps/arm/submul_1.S
diff --git a/ports/sysdeps/arm/submul_1.S b/ports/sysdeps/arm/submul_1.S
new file mode 100644
index 0000000..35e1348
--- /dev/null
+++ b/ports/sysdeps/arm/submul_1.S
@@ -0,0 +1,67 @@
+/* Copyright (C) 2013 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C 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 C 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 C Library. If not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+
+ .syntax unified
+ .text
+
+@ cycles/limb
+@ StrongArm ?
+@ Cortex-A8 ?
+@ Cortex-A9 ?
+@ Cortex-A15 4
+
+/* mp_limb_t mpn_submul_1(res_ptr, src1_ptr, size, s2_limb) */
+
+ENTRY(__mpn_submul_1)
+ push { r4, r5, r6, r7 }
+ cfi_adjust_cfa_offset (16)
+ cfi_rel_offset (r4, 0)
+ cfi_rel_offset (r5, 4)
+ cfi_rel_offset (r6, 8)
+ cfi_rel_offset (r7, 12)
+
+ ldr r6, [r1], #4
+ ldr r7, [r0]
+ mov r4, #0 /* init carry in */
+ b 1f
+0:
+ ldr r6, [r1], #4 /* load next ul */
+ adds r5, r5, r4 /* (lpl, c) = lpl + cl */
+ adc r4, ip, #0 /* cl = hpl + c */
+ subs r5, r7, r5 /* (lpl, !c) = rl - lpl */
+ ldr r7, [r0, #4] /* load next rl */
+ it cc
+ addcc r4, r4, #1 /* cl += !c */
+ str r5, [r0], #4
+1:
+ umull r5, ip, r6, r3 /* (hpl, lpl) = ul * vl */
+ subs r2, r2, #1
+ bne 0b
+
+ adds r5, r5, r4 /* (lpl, c) = lpl + cl */
+ adc r4, ip, #0 /* cl = hpl + c */
+ subs r5, r7, r5 /* (lpl, !c) = rl - lpl */
+ str r5, [r0], #4
+ ite cc
+ addcc r0, r4, #1 /* cl += !c */
+ movcs r0, r4 /* return carry */
+
+ pop { r4, r5, r6, r7 }
+ DO_RET(lr)
+END(__mpn_submul_1)
--
1.8.1.2
next prev parent reply other threads:[~2013-03-01 17:36 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-01 17:36 [PATCH v2 00/14] ARM improvements Richard Henderson
2013-03-01 17:36 ` Richard Henderson [this message]
2013-03-01 17:58 ` [PATCH v2 13/14] arm: Add optimized submul_1 Roland McGrath
2013-03-06 1:14 ` Joseph S. Myers
2013-03-01 17:36 ` [PATCH v2 11/14] arm: Add optimized ffs for armv6t2 Richard Henderson
2013-03-05 2:08 ` Joseph S. Myers
2013-03-06 15:52 ` Richard Henderson
2013-03-01 17:36 ` [PATCH v2 06/14] arm: Delete LOADREGS macro Richard Henderson
2013-03-01 17:36 ` [PATCH v2 09/14] arm: Tidy architecture selection Richard Henderson
2013-03-01 17:55 ` Roland McGrath
2013-03-05 2:01 ` Joseph S. Myers
2013-03-01 17:36 ` [PATCH v2 05/14] arm: Use push/pop mnemonics Richard Henderson
2013-03-01 17:36 ` [PATCH v2 14/14] arm: Add optimized add_n and sub_n Richard Henderson
2013-03-01 17:59 ` Roland McGrath
2013-03-06 0:53 ` Joseph S. Myers
2013-03-01 17:36 ` [PATCH v2 10/14] arm: Implement hard-tp for GET_TLS Richard Henderson
2013-03-01 17:55 ` Roland McGrath
2013-03-05 2:01 ` Joseph S. Myers
2013-03-01 17:36 ` [PATCH v2 08/14] arm: Unless arm4t, pop return address directly into pc Richard Henderson
2013-03-01 17:36 ` [PATCH v2 01/14] arm: Introduce and use LDST_PCREL Richard Henderson
2013-03-04 17:47 ` Joseph S. Myers
2013-03-01 17:36 ` [PATCH v2 04/14] arm: Enable thumb2 mode in assembly files Richard Henderson
2013-03-01 17:36 ` [PATCH v2 03/14] arm: Introduce and use GET_TLS Richard Henderson
2013-03-01 17:57 ` Roland McGrath
2013-03-05 1:45 ` Joseph S. Myers
2013-03-01 17:36 ` [PATCH v2 07/14] arm: Commonize BX conditionals Richard Henderson
2013-03-01 17:36 ` [PATCH v2 02/14] arm: Introduce and use NEGOFF series of macros Richard Henderson
2013-03-01 17:57 ` Roland McGrath
2013-03-05 1:42 ` Joseph S. Myers
2013-03-01 17:36 ` [PATCH v2 12/14] arm: Add optimized addmul_1 Richard Henderson
2013-03-01 17:58 ` Roland McGrath
2013-03-01 18:00 ` Roland McGrath
2013-03-06 1:18 ` Joseph S. Myers
2013-10-25 22:13 ` Roland McGrath
2013-03-06 1:11 ` Joseph S. Myers
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