1 files changed, 29 insertions, 0 deletions
diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h
index d4f21c947f..c27d3dc898 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
 
 /**