* [Qemu-devel] [PATCH 0/2] Fix qdev 32-bit compilation
@ 2013-07-30 18:18 Richard Henderson
2013-07-30 18:18 ` [Qemu-devel] [PATCH 1/2] qdev: Fix 32-bit compilation in print_size Richard Henderson
2013-07-30 18:18 ` [Qemu-devel] [PATCH 2/2] qdev: Use clz " Richard Henderson
0 siblings, 2 replies; 3+ messages in thread
From: Richard Henderson @ 2013-07-30 18:18 UTC (permalink / raw)
To: qemu-devel
Cc: vasilis.liaskovitis, imammedo, aliguori, Richard Henderson, afaerber
From: Richard Henderson <rth@grit.twiddle.net>
The patch e8cd45c78f53501e75bd455140da63d1b7ed3685 broke
compilation on 32-bit with a 40-bit shift of "long int".
The first patch is the trivial fix for that bug.
The second patch is an optional improvement that avoids
the division loop entirely.
r~
Richard Henderson (2):
qdev: Fix 32-bit compilation in print_size
qdev: Use clz in print_size
hw/core/qdev-properties.c | 20 +++++++++++++-------
1 file changed, 13 insertions(+), 7 deletions(-)
--
1.8.3.1
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Qemu-devel] [PATCH 1/2] qdev: Fix 32-bit compilation in print_size
2013-07-30 18:18 [Qemu-devel] [PATCH 0/2] Fix qdev 32-bit compilation Richard Henderson
@ 2013-07-30 18:18 ` Richard Henderson
2013-07-30 18:18 ` [Qemu-devel] [PATCH 2/2] qdev: Use clz " Richard Henderson
1 sibling, 0 replies; 3+ messages in thread
From: Richard Henderson @ 2013-07-30 18:18 UTC (permalink / raw)
To: qemu-devel
Cc: vasilis.liaskovitis, imammedo, aliguori, Richard Henderson, afaerber
From: Richard Henderson <rth@grit.twiddle.net>
Signed-off-by: Richard Henderson <rth@grit.twiddle.net>
---
hw/core/qdev-properties.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
index 8d43a8d..d6d10c9 100644
--- a/hw/core/qdev-properties.c
+++ b/hw/core/qdev-properties.c
@@ -1177,7 +1177,7 @@ static int print_size(DeviceState *dev, Property *prop, char *dest, size_t len)
int i = 0;
uint64_t div;
- for (div = (long int)1 << 40; !(*ptr / div) ; div >>= 10) {
+ for (div = 1ULL << 40; !(*ptr / div) ; div >>= 10) {
i++;
}
return snprintf(dest, len, "%0.03f%c", (double)*ptr/div, suffixes[i]);
--
1.8.3.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [Qemu-devel] [PATCH 2/2] qdev: Use clz in print_size
2013-07-30 18:18 [Qemu-devel] [PATCH 0/2] Fix qdev 32-bit compilation Richard Henderson
2013-07-30 18:18 ` [Qemu-devel] [PATCH 1/2] qdev: Fix 32-bit compilation in print_size Richard Henderson
@ 2013-07-30 18:18 ` Richard Henderson
1 sibling, 0 replies; 3+ messages in thread
From: Richard Henderson @ 2013-07-30 18:18 UTC (permalink / raw)
To: qemu-devel
Cc: vasilis.liaskovitis, imammedo, aliguori, Richard Henderson, afaerber
From: Richard Henderson <rth@grit.twiddle.net>
We can compute a floor log2 value with clz rather than a division loop.
Signed-off-by: Richard Henderson <rth@grit.twiddle.net>
---
hw/core/qdev-properties.c | 20 +++++++++++++-------
1 file changed, 13 insertions(+), 7 deletions(-)
diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
index d6d10c9..dc8ae69 100644
--- a/hw/core/qdev-properties.c
+++ b/hw/core/qdev-properties.c
@@ -1172,15 +1172,21 @@ static int parse_size(DeviceState *dev, Property *prop, const char *str)
static int print_size(DeviceState *dev, Property *prop, char *dest, size_t len)
{
- uint64_t *ptr = qdev_get_prop_ptr(dev, prop);
- char suffixes[] = {'T', 'G', 'M', 'K', 'B'};
- int i = 0;
- uint64_t div;
+ static const char suffixes[] = { 'B', 'K', 'M', 'G', 'T' };
+ uint64_t div, val = *(uint64_t *)qdev_get_prop_ptr(dev, prop);
+ int i;
- for (div = 1ULL << 40; !(*ptr / div) ; div >>= 10) {
- i++;
+ /* Compute floor(log2(val)). */
+ i = 64 - clz64(val);
+
+ /* Find the power of 1024 that we'll display as the units. */
+ i /= 10;
+ if (i >= ARRAY_SIZE(suffixes)) {
+ i = ARRAY_SIZE(suffixes) - 1;
}
- return snprintf(dest, len, "%0.03f%c", (double)*ptr/div, suffixes[i]);
+ div = 1ULL << (i * 10);
+
+ return snprintf(dest, len, "%0.03f%c", (double)val/div, suffixes[i]);
}
PropertyInfo qdev_prop_size = {
--
1.8.3.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
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2013-07-30 18:18 [Qemu-devel] [PATCH 0/2] Fix qdev 32-bit compilation Richard Henderson
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2013-07-30 18:18 ` [Qemu-devel] [PATCH 2/2] qdev: Use clz " Richard Henderson
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