76 lines
2.6 KiB
Diff
76 lines
2.6 KiB
Diff
From d9fa07a04ee19ad713b053f6a649178361d822a8 Mon Sep 17 00:00:00 2001
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From: Paolo Bonzini <pbonzini@redhat.com>
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Date: Fri, 16 Jul 2021 16:51:31 -0400
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Subject: [PATCH 15/43] osdep: provide ROUND_DOWN macro
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RH-Author: Miroslav Rezanina <mrezanin@redhat.com>
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RH-Bugzilla: 1957194
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osdep.h provides a ROUND_UP macro to hide bitwise operations for the
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purpose of rounding a number up to a power of two; add a ROUND_DOWN
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macro that does the same with truncation towards zero.
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While at it, change the formatting of some comments.
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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(cherry picked from commit c9797456f64ce72c03eb2969d97ac1dd4698d91e)
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Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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include/qemu/osdep.h | 28 ++++++++++++++++++++++------
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1 file changed, 22 insertions(+), 6 deletions(-)
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diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
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index cb2a07e472..e327220992 100644
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--- a/include/qemu/osdep.h
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+++ b/include/qemu/osdep.h
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@@ -316,11 +316,16 @@ extern "C" {
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})
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#endif
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-/* Round number down to multiple */
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+/*
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+ * Round number down to multiple. Safe when m is not a power of 2 (see
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+ * ROUND_DOWN for a faster version when a power of 2 is guaranteed).
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+ */
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#define QEMU_ALIGN_DOWN(n, m) ((n) / (m) * (m))
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-/* Round number up to multiple. Safe when m is not a power of 2 (see
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- * ROUND_UP for a faster version when a power of 2 is guaranteed) */
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+/*
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+ * Round number up to multiple. Safe when m is not a power of 2 (see
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+ * ROUND_UP for a faster version when a power of 2 is guaranteed).
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+ */
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#define QEMU_ALIGN_UP(n, m) QEMU_ALIGN_DOWN((n) + (m) - 1, (m))
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/* Check if n is a multiple of m */
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@@ -337,11 +342,22 @@ extern "C" {
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/* Check if pointer p is n-bytes aligned */
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#define QEMU_PTR_IS_ALIGNED(p, n) QEMU_IS_ALIGNED((uintptr_t)(p), (n))
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-/* Round number up to multiple. Requires that d be a power of 2 (see
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+/*
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+ * Round number down to multiple. Requires that d be a power of 2 (see
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* QEMU_ALIGN_UP for a safer but slower version on arbitrary
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- * numbers); works even if d is a smaller type than n. */
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+ * numbers); works even if d is a smaller type than n.
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+ */
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+#ifndef ROUND_DOWN
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+#define ROUND_DOWN(n, d) ((n) & -(0 ? (n) : (d)))
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+#endif
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+
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+/*
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+ * Round number up to multiple. Requires that d be a power of 2 (see
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+ * QEMU_ALIGN_UP for a safer but slower version on arbitrary
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+ * numbers); works even if d is a smaller type than n.
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+ */
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#ifndef ROUND_UP
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-#define ROUND_UP(n, d) (((n) + (d) - 1) & -(0 ? (n) : (d)))
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+#define ROUND_UP(n, d) ROUND_DOWN((n) + (d) - 1, (d))
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#endif
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#ifndef DIV_ROUND_UP
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--
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2.27.0
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