RE: [PATCH v3 06/19] range: Introduce range_get_last_bit()
>-Original Message-
>From: Cédric Le Goater
>Subject: Re: [PATCH v3 06/19] range: Introduce range_get_last_bit()
>
>On 4/30/24 11:58, Duan, Zhenzhong wrote:
>>
>>
>>> -Original Message-
>>> From: Cédric Le Goater
>>> Subject: Re: [PATCH v3 06/19] range: Introduce range_get_last_bit()
>>>
>>> On 4/29/24 08:50, Zhenzhong Duan wrote:
>>>> This helper get the highest 1 bit position of the upper bound.
>>>>
>>>> If the range is empty or upper bound is zero, -1 is returned.
>>>>
>>>> Suggested-by: Cédric Le Goater
>>>> Signed-off-by: Zhenzhong Duan
>>>> ---
>>>>include/qemu/range.h | 11 +++
>>>>1 file changed, 11 insertions(+)
>>>>
>>>> diff --git a/include/qemu/range.h b/include/qemu/range.h
>>>> index 205e1da76d..8e05bc1d9f 100644
>>>> --- a/include/qemu/range.h
>>>> +++ b/include/qemu/range.h
>>>> @@ -20,6 +20,8 @@
>>>>#ifndef QEMU_RANGE_H
>>>>#define QEMU_RANGE_H
>>>>
>>>> +#include "qemu/bitops.h"
>>>> +
>>>>/*
>>>> * Operations on 64 bit address ranges.
>>>> * Notes:
>>>> @@ -217,6 +219,15 @@ static inline int ranges_overlap(uint64_t first1,
>>> uint64_t len1,
>>>>return !(last2 < first1 || last1 < first2);
>>>>}
>>>>
>>>> +/* Get highest non-zero bit position of a range */
>>>> +static inline int range_get_last_bit(Range *range)
>>>> +{
>>>> +if (range_is_empty(range) || !range->upb) {
>>>> +return -1;
>>>> +}
>>>> +return find_last_bit(>upb, sizeof(range->upb));
>>>
>>> This breaks builds on 32-bit host systems.
>>
>> Oh, I missed 32bit build. Thanks, will fix.
>
>This should provide the same result ?
>
> return 63 - clz64(range->upb);
Yes, I tried 32bit and 64bit, it works. Will use it, thanks for suggestion.
BRs.
Zhenzhong
Re: [PATCH v3 06/19] range: Introduce range_get_last_bit()
On 4/30/24 11:58, Duan, Zhenzhong wrote:
-Original Message-
From: Cédric Le Goater
Subject: Re: [PATCH v3 06/19] range: Introduce range_get_last_bit()
On 4/29/24 08:50, Zhenzhong Duan wrote:
This helper get the highest 1 bit position of the upper bound.
If the range is empty or upper bound is zero, -1 is returned.
Suggested-by: Cédric Le Goater
Signed-off-by: Zhenzhong Duan
---
include/qemu/range.h | 11 +++
1 file changed, 11 insertions(+)
diff --git a/include/qemu/range.h b/include/qemu/range.h
index 205e1da76d..8e05bc1d9f 100644
--- a/include/qemu/range.h
+++ b/include/qemu/range.h
@@ -20,6 +20,8 @@
#ifndef QEMU_RANGE_H
#define QEMU_RANGE_H
+#include "qemu/bitops.h"
+
/*
* Operations on 64 bit address ranges.
* Notes:
@@ -217,6 +219,15 @@ static inline int ranges_overlap(uint64_t first1,
uint64_t len1,
return !(last2 < first1 || last1 < first2);
}
+/* Get highest non-zero bit position of a range */
+static inline int range_get_last_bit(Range *range)
+{
+if (range_is_empty(range) || !range->upb) {
+return -1;
+}
+return find_last_bit(>upb, sizeof(range->upb));
This breaks builds on 32-bit host systems.
Oh, I missed 32bit build. Thanks, will fix.
This should provide the same result ?
return 63 - clz64(range->upb);
Thanks,
C.
RE: [PATCH v3 06/19] range: Introduce range_get_last_bit()
>-Original Message-
>From: Cédric Le Goater
>Subject: Re: [PATCH v3 06/19] range: Introduce range_get_last_bit()
>
>On 4/29/24 08:50, Zhenzhong Duan wrote:
>> This helper get the highest 1 bit position of the upper bound.
>>
>> If the range is empty or upper bound is zero, -1 is returned.
>>
>> Suggested-by: Cédric Le Goater
>> Signed-off-by: Zhenzhong Duan
>> ---
>> include/qemu/range.h | 11 +++
>> 1 file changed, 11 insertions(+)
>>
>> diff --git a/include/qemu/range.h b/include/qemu/range.h
>> index 205e1da76d..8e05bc1d9f 100644
>> --- a/include/qemu/range.h
>> +++ b/include/qemu/range.h
>> @@ -20,6 +20,8 @@
>> #ifndef QEMU_RANGE_H
>> #define QEMU_RANGE_H
>>
>> +#include "qemu/bitops.h"
>> +
>> /*
>>* Operations on 64 bit address ranges.
>>* Notes:
>> @@ -217,6 +219,15 @@ static inline int ranges_overlap(uint64_t first1,
>uint64_t len1,
>> return !(last2 < first1 || last1 < first2);
>> }
>>
>> +/* Get highest non-zero bit position of a range */
>> +static inline int range_get_last_bit(Range *range)
>> +{
>> +if (range_is_empty(range) || !range->upb) {
>> +return -1;
>> +}
>> +return find_last_bit(>upb, sizeof(range->upb));
>
>This breaks builds on 32-bit host systems.
Oh, I missed 32bit build. Thanks, will fix.
Thanks
zhenzhong
>
>
>Thanks,
>
>C.
>
>
>> +}
>> +
>> /*
>>* Return -1 if @a < @b, 1 @a > @b, and 0 if they touch or overlap.
>>* Both @a and @b must not be empty.
Re: [PATCH v3 06/19] range: Introduce range_get_last_bit()
On 4/29/24 08:50, Zhenzhong Duan wrote:
This helper get the highest 1 bit position of the upper bound.
If the range is empty or upper bound is zero, -1 is returned.
Suggested-by: Cédric Le Goater
Signed-off-by: Zhenzhong Duan
---
include/qemu/range.h | 11 +++
1 file changed, 11 insertions(+)
diff --git a/include/qemu/range.h b/include/qemu/range.h
index 205e1da76d..8e05bc1d9f 100644
--- a/include/qemu/range.h
+++ b/include/qemu/range.h
@@ -20,6 +20,8 @@
#ifndef QEMU_RANGE_H
#define QEMU_RANGE_H
+#include "qemu/bitops.h"
+
/*
* Operations on 64 bit address ranges.
* Notes:
@@ -217,6 +219,15 @@ static inline int ranges_overlap(uint64_t first1, uint64_t
len1,
return !(last2 < first1 || last1 < first2);
}
+/* Get highest non-zero bit position of a range */
+static inline int range_get_last_bit(Range *range)
+{
+if (range_is_empty(range) || !range->upb) {
+return -1;
+}
+return find_last_bit(>upb, sizeof(range->upb));
This breaks builds on 32-bit host systems.
Thanks,
C.
+}
+
/*
* Return -1 if @a < @b, 1 @a > @b, and 0 if they touch or overlap.
* Both @a and @b must not be empty.
