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