From: Wei Wang <wei.w.wang@intel.com>
To: xen-devel@lists.xen.org, jbeulich@suse.com
Cc: andrew.cooper3@citrix.com, Wei Wang <wei.w.wang@intel.com>
Subject: [PATCH v3 02/11] x86/intel_pstate: add some calculation related support
Date: Thu, 11 Jun 2015 16:26:29 +0800 [thread overview]
Message-ID: <1434011189-16804-1-git-send-email-wei.w.wang@intel.com> (raw)
The added calculation related functions will be used in the intel_pstate.c.
They are copied from the kernel(commit 2418f4f2, f3002134, eb18cba7).
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
---
xen/include/asm-x86/div64.h | 72 +++++++++++++++++++++++++++++++++++++++++++++
xen/include/xen/kernel.h | 12 ++++++++
2 files changed, 84 insertions(+)
diff --git a/xen/include/asm-x86/div64.h b/xen/include/asm-x86/div64.h
index dd49f64..daeb065 100644
--- a/xen/include/asm-x86/div64.h
+++ b/xen/include/asm-x86/div64.h
@@ -11,4 +11,76 @@
__rem; \
})
+static inline uint64_t div_u64_rem(uint64_t dividend, uint32_t divisor,
+ uint32_t *remainder)
+{
+ *remainder = do_div(dividend, divisor);
+ return dividend;
+}
+
+static inline uint64_t div_u64(uint64_t dividend, uint32_t divisor)
+{
+ uint32_t remainder;
+ return div_u64_rem(dividend, divisor, &remainder);
+}
+
+/*
+ * div64_u64 - unsigned 64bit divide with 64bit divisor
+ * @dividend: 64bit dividend
+ * @divisor: 64bit divisor
+ *
+ * This implementation is a modified version of the algorithm proposed
+ * by the book 'Hacker's Delight'. The original source and full proof
+ * can be found here and is available for use without restriction.
+ *
+ * 'http://www.hackersdelight.org/HDcode/newCode/divDouble.c.txt'
+ */
+static inline uint64_t div64_u64(uint64_t dividend, uint64_t divisor)
+{
+ uint32_t high = divisor >> 32;
+ uint64_t quot;
+
+ if (high == 0) {
+ quot = div_u64(dividend, divisor);
+ } else {
+ int n = 1 + fls(high);
+ quot = div_u64(dividend >> n, divisor >> n);
+
+ if (quot != 0)
+ quot--;
+ if ((dividend - quot * divisor) >= divisor)
+ quot++;
+ }
+ return quot;
+}
+
+static inline int64_t div_s64_rem(int64_t dividend, int32_t divisor,
+ int32_t *remainder)
+{
+ int64_t quotient;
+
+ if (dividend < 0) {
+ quotient = div_u64_rem(-dividend, ABS(divisor),
+ (uint32_t *)remainder);
+ *remainder = -*remainder;
+ if (divisor > 0)
+ quotient = -quotient;
+ } else {
+ quotient = div_u64_rem(dividend, ABS(divisor),
+ (uint32_t *)remainder);
+ if (divisor < 0)
+ quotient = -quotient;
+ }
+ return quotient;
+}
+
+/*
+ * div_s64 - signed 64bit divide with 32bit divisor
+ */
+static inline int64_t div_s64(int64_t dividend, int32_t divisor)
+{
+ int32_t remainder;
+ return div_s64_rem(dividend, divisor, &remainder);
+}
+
#endif
diff --git a/xen/include/xen/kernel.h b/xen/include/xen/kernel.h
index 548b64d..bfdcdb6 100644
--- a/xen/include/xen/kernel.h
+++ b/xen/include/xen/kernel.h
@@ -42,6 +42,18 @@
#define MIN(x,y) ((x) < (y) ? (x) : (y))
#define MAX(x,y) ((x) > (y) ? (x) : (y))
+/*
+ * clamp_t - return a value clamped to a given range using a given type
+ * @type: the type of variable to use
+ * @val: current value
+ * @lo: minimum allowable value
+ * @hi: maximum allowable value
+ *
+ * This macro does no typechecking and uses temporary variables of type
+ * 'type' to make all the comparisons.
+ */
+#define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi)
+
/**
* container_of - cast a member of a structure out to the containing structure
*
--
1.9.1
next reply other threads:[~2015-06-11 8:26 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-11 8:26 Wei Wang [this message]
2015-06-18 14:07 ` [PATCH v3 02/11] x86/intel_pstate: add some calculation related support Jan Beulich
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