From: vijay.kilari@gmail.com
To: Ian.Campbell@citrix.com, julien.grall@citrix.com,
stefano.stabellini@eu.citrix.com, stefano.stabellini@citrix.com,
tim@xen.org, xen-devel@lists.xen.org
Cc: Keir Fraser <keir@xen.org>,
Ian Campbell <ian.campbell@citrix.com>,
vijay.kilari@gmail.com, Prasun.Kapoor@caviumnetworks.com,
Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com>,
Ian Jackson <ian.jackson@eu.citrix.com>,
Jan Beulich <jbeulich@suse.com>,
manish.jaggi@caviumnetworks.com
Subject: [PATCH v6 03/31] xen: Add log2 functionality
Date: Mon, 31 Aug 2015 16:36:20 +0530 [thread overview]
Message-ID: <1441019208-2764-4-git-send-email-vijay.kilari@gmail.com> (raw)
In-Reply-To: <1441019208-2764-1-git-send-email-vijay.kilari@gmail.com>
From: Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com>
log2 helper apis are ported from linux from
commit 13c07b0286d340275f2d97adf085cecda37ede37
(linux/log2.h: Fix rounddown_pow_of_two(1))
Changes made for xen are:
- Only required functionality is retained
- Replace fls_long with flsl
Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com>
CC: Ian Campbell <ian.campbell@citrix.com>
CC: Ian Jackson <ian.jackson@eu.citrix.com>
CC: Jan Beulich <jbeulich@suse.com>
CC: Keir Fraser <keir@xen.org>
CC: Tim Deegan <tim@xen.org>
---
v4: - Only retained required functionality
- Replaced fls_long with flsl
- Removed fls_long implementation in bitops.h in v3 version
---
xen/include/xen/log2.h | 167 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 167 insertions(+)
diff --git a/xen/include/xen/log2.h b/xen/include/xen/log2.h
new file mode 100644
index 0000000..86bd861
--- /dev/null
+++ b/xen/include/xen/log2.h
@@ -0,0 +1,167 @@
+/*
+ * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program 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
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _XEN_LOG2_H
+#define _XEN_LOG2_H
+
+#include <xen/types.h>
+#include <xen/bitops.h>
+
+/*
+ * deal with unrepresentable constant logarithms
+ */
+extern __attribute__((const))
+int ____ilog2_NaN(void);
+
+/*
+ * non-constant log of base 2 calculators
+ * - the arch may override these in asm/bitops.h if they can be implemented
+ * more efficiently than using fls() and fls64()
+ * - the arch is not required to handle n==0 if implementing the fallback
+ */
+static inline __attribute__((const))
+int __ilog2_u32(u32 n)
+{
+ return fls(n) - 1;
+}
+
+static inline __attribute__((const))
+int __ilog2_u64(u64 n)
+{
+ return flsl(n) - 1;
+}
+
+/*
+ * round up to nearest power of two
+ */
+static inline __attribute__((const))
+unsigned long __roundup_pow_of_two(unsigned long n)
+{
+ return 1UL << flsl(n - 1);
+}
+
+/**
+ * ilog2 - log of base 2 of 32-bit or a 64-bit unsigned value
+ * @n - parameter
+ *
+ * constant-capable log of base 2 calculation
+ * - this can be used to initialise global variables from constant data, hence
+ * the massive ternary operator construction
+ *
+ * selects the appropriately-sized optimised version depending on sizeof(n)
+ */
+#define ilog2(n) \
+( \
+ __builtin_constant_p(n) ? ( \
+ (n) < 1 ? ____ilog2_NaN() : \
+ (n) & (1ULL << 63) ? 63 : \
+ (n) & (1ULL << 62) ? 62 : \
+ (n) & (1ULL << 61) ? 61 : \
+ (n) & (1ULL << 60) ? 60 : \
+ (n) & (1ULL << 59) ? 59 : \
+ (n) & (1ULL << 58) ? 58 : \
+ (n) & (1ULL << 57) ? 57 : \
+ (n) & (1ULL << 56) ? 56 : \
+ (n) & (1ULL << 55) ? 55 : \
+ (n) & (1ULL << 54) ? 54 : \
+ (n) & (1ULL << 53) ? 53 : \
+ (n) & (1ULL << 52) ? 52 : \
+ (n) & (1ULL << 51) ? 51 : \
+ (n) & (1ULL << 50) ? 50 : \
+ (n) & (1ULL << 49) ? 49 : \
+ (n) & (1ULL << 48) ? 48 : \
+ (n) & (1ULL << 47) ? 47 : \
+ (n) & (1ULL << 46) ? 46 : \
+ (n) & (1ULL << 45) ? 45 : \
+ (n) & (1ULL << 44) ? 44 : \
+ (n) & (1ULL << 43) ? 43 : \
+ (n) & (1ULL << 42) ? 42 : \
+ (n) & (1ULL << 41) ? 41 : \
+ (n) & (1ULL << 40) ? 40 : \
+ (n) & (1ULL << 39) ? 39 : \
+ (n) & (1ULL << 38) ? 38 : \
+ (n) & (1ULL << 37) ? 37 : \
+ (n) & (1ULL << 36) ? 36 : \
+ (n) & (1ULL << 35) ? 35 : \
+ (n) & (1ULL << 34) ? 34 : \
+ (n) & (1ULL << 33) ? 33 : \
+ (n) & (1ULL << 32) ? 32 : \
+ (n) & (1ULL << 31) ? 31 : \
+ (n) & (1ULL << 30) ? 30 : \
+ (n) & (1ULL << 29) ? 29 : \
+ (n) & (1ULL << 28) ? 28 : \
+ (n) & (1ULL << 27) ? 27 : \
+ (n) & (1ULL << 26) ? 26 : \
+ (n) & (1ULL << 25) ? 25 : \
+ (n) & (1ULL << 24) ? 24 : \
+ (n) & (1ULL << 23) ? 23 : \
+ (n) & (1ULL << 22) ? 22 : \
+ (n) & (1ULL << 21) ? 21 : \
+ (n) & (1ULL << 20) ? 20 : \
+ (n) & (1ULL << 19) ? 19 : \
+ (n) & (1ULL << 18) ? 18 : \
+ (n) & (1ULL << 17) ? 17 : \
+ (n) & (1ULL << 16) ? 16 : \
+ (n) & (1ULL << 15) ? 15 : \
+ (n) & (1ULL << 14) ? 14 : \
+ (n) & (1ULL << 13) ? 13 : \
+ (n) & (1ULL << 12) ? 12 : \
+ (n) & (1ULL << 11) ? 11 : \
+ (n) & (1ULL << 10) ? 10 : \
+ (n) & (1ULL << 9) ? 9 : \
+ (n) & (1ULL << 8) ? 8 : \
+ (n) & (1ULL << 7) ? 7 : \
+ (n) & (1ULL << 6) ? 6 : \
+ (n) & (1ULL << 5) ? 5 : \
+ (n) & (1ULL << 4) ? 4 : \
+ (n) & (1ULL << 3) ? 3 : \
+ (n) & (1ULL << 2) ? 2 : \
+ (n) & (1ULL << 1) ? 1 : \
+ (n) & (1ULL << 0) ? 0 : \
+ ____ilog2_NaN() \
+ ) : \
+ (sizeof(n) <= 4) ? \
+ __ilog2_u32(n) : \
+ __ilog2_u64(n) \
+ )
+
+/**
+ * roundup_pow_of_two - round the given value up to nearest power of two
+ * @n - parameter
+ *
+ * round the given value up to the nearest power of two
+ * - the result is undefined when n == 0
+ * - this can be used to initialise global variables from constant data
+ */
+#define roundup_pow_of_two(n) \
+( \
+ __builtin_constant_p(n) ? ( \
+ (n == 1) ? 1 : \
+ (1UL << (ilog2((n) - 1) + 1)) \
+ ) : \
+ __roundup_pow_of_two(n) \
+ )
+
+/**
+ * order_base_2 - calculate the (rounded up) base 2 order of the argument
+ * @n: parameter
+ *
+ * The first few values calculated by this routine:
+ * ob2(0) = 0
+ * ob2(1) = 0
+ * ob2(2) = 1
+ * ob2(3) = 2
+ * ob2(4) = 2
+ * ob2(5) = 3
+ * ... and so on.
+ */
+
+#define order_base_2(n) ilog2(roundup_pow_of_two(n))
+#endif /* _XEN_LOG2_H */
--
1.7.9.5
next prev parent reply other threads:[~2015-08-31 11:06 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-31 11:06 [PATCH v6 00/31] Add ITS support vijay.kilari
2015-08-31 11:06 ` [PATCH v6 01/31] xen/dt: Handle correctly node with interrupt-map in dt_for_each_irq_map vijay.kilari
2015-08-31 14:20 ` Julien Grall
2015-09-02 15:28 ` Ian Campbell
2015-09-02 15:30 ` Wei Liu
2015-09-02 15:45 ` Julien Grall
2015-09-02 15:52 ` Ian Campbell
2015-09-04 14:41 ` Ian Campbell
2015-08-31 11:06 ` [PATCH v6 02/31] xen/arm: Add bitmap_find_next_zero_area helper function vijay.kilari
2015-08-31 11:06 ` vijay.kilari [this message]
2015-08-31 11:21 ` [PATCH v6 03/31] xen: Add log2 functionality Jan Beulich
2015-08-31 11:06 ` [PATCH v6 04/31] xen/arm: Set nr_cpu_ids to available number of cpus vijay.kilari
2015-08-31 14:25 ` Julien Grall
2015-09-09 12:48 ` Ian Campbell
2015-08-31 11:06 ` [PATCH v6 05/31] xen/arm: Rename NR_IRQs and vgic_num_irqs helper function vijay.kilari
2015-08-31 14:40 ` Julien Grall
2015-09-09 13:08 ` Ian Campbell
2015-09-09 13:23 ` Julien Grall
2015-08-31 11:06 ` [PATCH v6 06/31] xen/arm: ITS: Port ITS driver to Xen vijay.kilari
2015-08-31 15:41 ` Julien Grall
2015-09-03 17:02 ` Julien Grall
2015-08-31 11:06 ` [PATCH v6 07/31] xen/arm: ITS: Add helper functions to manage its_devices vijay.kilari
2015-08-31 11:06 ` [PATCH v6 08/31] xen/arm: ITS: Introduce msi_desc for LPIs vijay.kilari
2015-08-31 16:20 ` Julien Grall
2015-09-09 13:16 ` Ian Campbell
2015-09-09 13:28 ` Julien Grall
2015-08-31 11:06 ` [PATCH v6 09/31] xen/arm: ITS: Add APIs to add and assign device vijay.kilari
2015-09-03 17:34 ` Julien Grall
2015-09-09 13:28 ` Ian Campbell
2015-09-09 13:44 ` Julien Grall
2015-09-09 15:07 ` Ian Campbell
2015-09-09 16:19 ` Julien Grall
2015-08-31 11:06 ` [PATCH v6 10/31] xen/arm: ITS: Introduce gic_is_lpi helper function vijay.kilari
2015-08-31 16:49 ` Julien Grall
2015-09-01 9:02 ` Vijay Kilari
2015-09-01 11:40 ` Julien Grall
2015-09-01 11:56 ` Vijay Kilari
2015-09-01 13:02 ` Julien Grall
2015-09-03 6:32 ` Vijay Kilari
2015-09-03 9:48 ` Julien Grall
2015-08-31 11:06 ` [PATCH v6 11/31] xen/arm: ITS: Enable compilation of physical ITS driver vijay.kilari
2015-08-31 11:06 ` [PATCH v6 12/31] xen/arm: Move vgic locking inside get_irq_priority callback vijay.kilari
2015-08-31 16:34 ` Julien Grall
2015-08-31 11:06 ` [PATCH v6 13/31] xen/arm: ITS: implement hw_irq_controller for LPIs vijay.kilari
2015-08-31 17:53 ` Julien Grall
2015-08-31 11:06 ` [PATCH v6 14/31] xen/arm: ITS: Initialize physical ITS and export lpi support vijay.kilari
2015-08-31 18:35 ` Julien Grall
2015-08-31 11:06 ` [PATCH v6 15/31] xen/arm: ITS: Add virtual ITS driver vijay.kilari
2015-09-02 17:20 ` Julien Grall
2015-08-31 11:06 ` [PATCH v6 16/31] xen/arm: ITS: Add virtual ITS commands support vijay.kilari
2015-09-03 15:07 ` Julien Grall
2015-08-31 11:06 ` [PATCH v6 17/31] xen/arm: ITS: Store LPIs allocated and IRQ ID bits per domain vijay.kilari
2015-09-03 16:25 ` Julien Grall
2015-09-07 6:59 ` Vijay Kilari
2015-09-07 10:56 ` Julien Grall
2015-08-31 11:06 ` [PATCH v6 18/31] xen/arm: ITS: Enable virtual ITS driver vijay.kilari
2015-08-31 11:06 ` [PATCH v6 19/31] xen/arm: ITS: Export ITS info to Virtual ITS vijay.kilari
2015-09-03 16:48 ` Julien Grall
2015-08-31 11:06 ` [PATCH v6 20/31] xen/arm: ITS: Introduce helper to get number of event IDs vijay.kilari
2015-09-03 17:51 ` Julien Grall
2015-08-31 11:06 ` [PATCH v6 21/31] xen/arm: ITS: Add GITS registers emulation vijay.kilari
2015-09-07 13:14 ` Julien Grall
2015-08-31 11:06 ` [PATCH v6 22/31] xen/arm: ITS: Add virtual ITS availability check helper vijay.kilari
2015-09-07 13:41 ` Julien Grall
2015-08-31 11:06 ` [PATCH v6 23/31] xen/arm: ITS: Add 32-bit access to GICR_TYPER vijay.kilari
2015-08-31 16:06 ` Julien Grall
2015-08-31 11:06 ` [PATCH v6 24/31] xen/arm: ITS: Add GICR register emulation vijay.kilari
2015-09-07 14:20 ` Julien Grall
2015-09-07 15:26 ` Vijay Kilari
2015-09-09 13:55 ` Ian Campbell
2015-09-09 16:11 ` Julien Grall
2015-08-31 11:06 ` [PATCH v6 25/31] xen/arm: ITS: Allocate irq descriptors for LPIs vijay.kilari
2015-08-31 11:06 ` [PATCH v6 26/31] xen/arm: ITS: Allocate pending_lpi " vijay.kilari
2015-08-31 11:06 ` [PATCH v6 27/31] xen/arm: ITS: Route LPIs vijay.kilari
2015-08-31 11:06 ` [PATCH v6 28/31] xen/arm: ITS: Add domain specific ITS initialization vijay.kilari
2015-08-31 11:06 ` [PATCH v6 29/31] xen/arm: ITS: Map ITS translation space vijay.kilari
2015-08-31 19:07 ` Julien Grall
2015-08-31 11:06 ` [PATCH v6 30/31] xen/arm: ITS: Generate ITS node for Dom0 vijay.kilari
2015-08-31 11:06 ` [PATCH v6 31/31] xen/arm: ITS: Add pci devices in ThunderX vijay.kilari
2015-09-09 15:22 ` Ian Campbell
2015-09-02 15:38 ` [PATCH v6 00/31] Add ITS support Ian Campbell
2015-09-02 15:52 ` Ian Campbell
2015-09-03 16:45 ` Julien Grall
2015-09-09 15:29 ` Ian Campbell
2015-09-14 11:00 ` Vijay Kilari
2015-09-14 11:09 ` Julien Grall
2015-09-14 13:04 ` Vijay Kilari
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