From: Richard Henderson <rth@twiddle.net>
To: libc-ports@sourceware.org
Cc: joseph@codesourcery.com
Subject: [PATCH v2 14/14] arm: Add optimized add_n and sub_n
Date: Fri, 01 Mar 2013 17:36:00 -0000 [thread overview]
Message-ID: <1362159320-5934-15-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 LGPL 2.1 vs
GPL 3, but tested with the GMP testsuite.
This is 250% faster than the generic code as measured on Cortex-A15,
and the same speed as GMP on the same core, and probably everywhere.
---
* sysdeps/arm/add_n.S: New file.
* sysdeps/arm/sub_n.S: New file.
---
ports/sysdeps/arm/add_n.S | 83 +++++++++++++++++++++++++++++++++++++++++++++++
ports/sysdeps/arm/sub_n.S | 2 ++
2 files changed, 85 insertions(+)
create mode 100644 ports/sysdeps/arm/add_n.S
create mode 100644 ports/sysdeps/arm/sub_n.S
diff --git a/ports/sysdeps/arm/add_n.S b/ports/sysdeps/arm/add_n.S
new file mode 100644
index 0000000..af69733
--- /dev/null
+++ b/ports/sysdeps/arm/add_n.S
@@ -0,0 +1,83 @@
+/* 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
+
+#ifdef USE_AS_SUB_N
+# define INITC cmp r0, r0
+# define OPC sbcs
+# define RETC sbc r0, r0, r0; neg r0, r0
+# define FUNC __mpn_sub_n
+#else
+# define INITC cmn r0, #0
+# define OPC adcs
+# define RETC mov r0, #0; adc r0, r0, r0
+# define FUNC __mpn_add_n
+#endif
+
+/* mp_limb_t mpn_add_n(res_ptr, src1_ptr, src2_ptr, size) */
+
+ENTRY (FUNC)
+ push { r4, r5, r6, r7, r8, r10, lr }
+ cfi_adjust_cfa_offset (28)
+ cfi_rel_offset (r4, 0)
+ cfi_rel_offset (r5, 4)
+ cfi_rel_offset (r6, 8)
+ cfi_rel_offset (r7, 12)
+ cfi_rel_offset (r8, 16)
+ cfi_rel_offset (r10, 20)
+ cfi_rel_offset (lr, 24)
+
+ INITC /* initialize carry flag */
+ tst r3, #1 /* count & 1 == 1? */
+ add lr, r1, r3, lsl #2 /* compute end src1 */
+ beq 1f
+
+ ldr r4, [r1], #4 /* do one to make count even */
+ ldr r5, [r2], #4
+ OPC r4, r4, r5
+ teq r1, lr /* end of count? (preserve carry) */
+ str r4, [r0], #4
+ beq 9f
+1:
+ tst r3, #2 /* count & 2 == 2? */
+ beq 2f
+ ldm r1!, { r4, r5 } /* do two to make count 0 mod 4 */
+ ldm r2!, { r6, r7 }
+ OPC r4, r4, r6
+ OPC r5, r5, r7
+ teq r1, lr /* end of count? */
+ stm r0!, { r4, r5 }
+ beq 9f
+2:
+ ldm r1!, { r3, r5, r7, r10 } /* do four each loop */
+ ldm r2!, { r4, r6, r8, ip }
+ OPC r3, r3, r4
+ OPC r5, r5, r6
+ OPC r7, r7, r8
+ OPC r10, r10, ip
+ teq r1, lr
+ stm r0!, { r3, r5, r7, r10 }
+ bne 2b
+
+9:
+ RETC /* copy carry out */
+ pop { r4, r5, r6, r7, r8, r10, pc }
+END (FUNC)
diff --git a/ports/sysdeps/arm/sub_n.S b/ports/sysdeps/arm/sub_n.S
new file mode 100644
index 0000000..8eafa41
--- /dev/null
+++ b/ports/sysdeps/arm/sub_n.S
@@ -0,0 +1,2 @@
+#define USE_AS_SUB_N
+#include "add_n.S"
--
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 17:59 ` [PATCH v2 14/14] arm: Add optimized add_n and sub_n Roland McGrath
2013-03-06 0:53 ` 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 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 13/14] arm: Add optimized submul_1 Richard Henderson
2013-03-01 17:58 ` 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 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 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 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 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
2013-03-01 17:36 ` [PATCH v2 07/14] arm: Commonize BX conditionals Richard Henderson
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