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authorPeter Maydell <peter.maydell@linaro.org>2015-08-19 16:20:20 +0100
committerPeter Maydell <peter.maydell@linaro.org>2015-08-19 16:29:53 +0100
commit49caffe0cc95a9d0dc344e3328be8197f3536cf8 (patch)
tree6d78d17355987bd24ae1ae09bd50e4cb9eef777c /include/qemu/host-utils.h
parent03557b9abaee78e9d1ef5cd236d32a7b3e75e6f8 (diff)
downloadhqemu-49caffe0cc95a9d0dc344e3328be8197f3536cf8.zip
hqemu-49caffe0cc95a9d0dc344e3328be8197f3536cf8.tar.gz
qemu-common.h: Move muldiv64() to host-utils.h
Move the muldiv64() function from qemu-common.h to host-utils.h. This puts it together with all the other arithmetic functions where we provide a version with __int128_t and a fallback without, and allows headers which need muldiv64() to avoid including qemu-common.h. We don't include host-utils from qemu-common.h, to avoid dragging more things into qemu-common.h than it already has; in practice everywhere that needs muldiv64() can get it via qemu/timer.h. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Diffstat (limited to 'include/qemu/host-utils.h')
-rw-r--r--include/qemu/host-utils.h29
1 files changed, 29 insertions, 0 deletions
diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h
index d4f21c9..c27d3dc 100644
--- a/include/qemu/host-utils.h
+++ b/include/qemu/host-utils.h
@@ -45,6 +45,12 @@ static inline void muls64(uint64_t *plow, uint64_t *phigh,
*phigh = r >> 64;
}
+/* compute with 96 bit intermediate result: (a*b)/c */
+static inline uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c)
+{
+ return (__int128_t)a * b / c;
+}
+
static inline int divu128(uint64_t *plow, uint64_t *phigh, uint64_t divisor)
{
if (divisor == 0) {
@@ -75,6 +81,29 @@ void muls64(uint64_t *phigh, uint64_t *plow, int64_t a, int64_t b);
void mulu64(uint64_t *phigh, uint64_t *plow, uint64_t a, uint64_t b);
int divu128(uint64_t *plow, uint64_t *phigh, uint64_t divisor);
int divs128(int64_t *plow, int64_t *phigh, int64_t divisor);
+
+static inline uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c)
+{
+ union {
+ uint64_t ll;
+ struct {
+#ifdef HOST_WORDS_BIGENDIAN
+ uint32_t high, low;
+#else
+ uint32_t low, high;
+#endif
+ } l;
+ } u, res;
+ uint64_t rl, rh;
+
+ u.ll = a;
+ rl = (uint64_t)u.l.low * (uint64_t)b;
+ rh = (uint64_t)u.l.high * (uint64_t)b;
+ rh += (rl >> 32);
+ res.l.high = rh / c;
+ res.l.low = (((rh % c) << 32) + (rl & 0xffffffff)) / c;
+ return res.ll;
+}
#endif
/**
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