Merge remote-tracking branch 'remotes/thibault/tags/samuel-thibault' into staging

[qemu.git] / util / host-utils.c

diff --git a/util/host-utils.c b/util/host-utils.c
index 5e3915abba46911a1f221540749ecb2e57c834be..7b9322071d1d5a74d86dd15985a36a50deb13016 100644 (file)
--- a/util/host-utils.c
+++ b/util/host-utils.c
@@ -23,83 +23,205 @@
  * THE SOFTWARE.
  */
 
  * THE SOFTWARE.
  */
 

-#include <stdlib.h>
-#include <stdint.h>
+#include "qemu/osdep.h"

 #include "qemu/host-utils.h"
 
 #include "qemu/host-utils.h"
 

-//#define DEBUG_MULDIV
-
+#ifndef CONFIG_INT128

 /* Long integer helpers */
 /* Long integer helpers */

-#if !defined(__x86_64__)
-static void add128 (uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b)
+static inline void mul64(uint64_t *plow, uint64_t *phigh,
+                         uint64_t a, uint64_t b)

 {
 {

-    *plow += a;
-    /* carry test */
-    if (*plow < a)
-        (*phigh)++;
-    *phigh += b;
+    typedef union {
+        uint64_t ll;
+        struct {
+#ifdef HOST_WORDS_BIGENDIAN
+            uint32_t high, low;
+#else
+            uint32_t low, high;
+#endif
+        } l;
+    } LL;
+    LL rl, rm, rn, rh, a0, b0;
+    uint64_t c;
+
+    a0.ll = a;
+    b0.ll = b;
+
+    rl.ll = (uint64_t)a0.l.low * b0.l.low;
+    rm.ll = (uint64_t)a0.l.low * b0.l.high;
+    rn.ll = (uint64_t)a0.l.high * b0.l.low;
+    rh.ll = (uint64_t)a0.l.high * b0.l.high;
+
+    c = (uint64_t)rl.l.high + rm.l.low + rn.l.low;
+    rl.l.high = c;
+    c >>= 32;
+    c = c + rm.l.high + rn.l.high + rh.l.low;
+    rh.l.low = c;
+    rh.l.high += (uint32_t)(c >> 32);
+
+    *plow = rl.ll;
+    *phigh = rh.ll;

 }
 
 }
 

-static void neg128 (uint64_t *plow, uint64_t *phigh)
+/* Unsigned 64x64 -> 128 multiplication */
+void mulu64 (uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b)

 {
 {

-    *plow = ~*plow;
-    *phigh = ~*phigh;
-    add128(plow, phigh, 1, 0);
+    mul64(plow, phigh, a, b);

 }
 
 }
 

-static void mul64 (uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b)
+/* Signed 64x64 -> 128 multiplication */
+void muls64 (uint64_t *plow, uint64_t *phigh, int64_t a, int64_t b)

 {
 {

-    uint32_t a0, a1, b0, b1;
-    uint64_t v;
+    uint64_t rh;

 
 

-    a0 = a;
-    a1 = a >> 32;
+    mul64(plow, &rh, a, b);

 
 

-    b0 = b;
-    b1 = b >> 32;
+    /* Adjust for signs.  */
+    if (b < 0) {
+        rh -= a;
+    }
+    if (a < 0) {
+        rh -= b;
+    }
+    *phigh = rh;
+}

 
 

-    v = (uint64_t)a0 * (uint64_t)b0;
-    *plow = v;
-    *phigh = 0;
+/* Unsigned 128x64 division.  Returns 1 if overflow (divide by zero or */
+/* quotient exceeds 64 bits).  Otherwise returns quotient via plow and */
+/* remainder via phigh. */
+int divu128(uint64_t *plow, uint64_t *phigh, uint64_t divisor)
+{
+    uint64_t dhi = *phigh;
+    uint64_t dlo = *plow;
+    unsigned i;
+    uint64_t carry = 0;

 
 

-    v = (uint64_t)a0 * (uint64_t)b1;
-    add128(plow, phigh, v << 32, v >> 32);
+    if (divisor == 0) {
+        return 1;
+    } else if (dhi == 0) {
+        *plow  = dlo / divisor;
+        *phigh = dlo % divisor;
+        return 0;
+    } else if (dhi > divisor) {
+        return 1;
+    } else {

 
 

-    v = (uint64_t)a1 * (uint64_t)b0;
-    add128(plow, phigh, v << 32, v >> 32);
+        for (i = 0; i < 64; i++) {
+            carry = dhi >> 63;
+            dhi = (dhi << 1) | (dlo >> 63);
+            if (carry || (dhi >= divisor)) {
+                dhi -= divisor;
+                carry = 1;
+            } else {
+                carry = 0;
+            }
+            dlo = (dlo << 1) | carry;
+        }

 
 

-    v = (uint64_t)a1 * (uint64_t)b1;
-    *phigh += v;
+        *plow = dlo;
+        *phigh = dhi;
+        return 0;
+    }

 }
 
 }
 

-/* Unsigned 64x64 -> 128 multiplication */
-void mulu64 (uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b)
+int divs128(int64_t *plow, int64_t *phigh, int64_t divisor)

 {
 {

-    mul64(plow, phigh, a, b);
-#if defined(DEBUG_MULDIV)
-    printf("mulu64: 0x%016llx * 0x%016llx = 0x%016llx%016llx\n",
-           a, b, *phigh, *plow);
+    int sgn_dvdnd = *phigh < 0;
+    int sgn_divsr = divisor < 0;
+    int overflow = 0;
+
+    if (sgn_dvdnd) {
+        *plow = ~(*plow);
+        *phigh = ~(*phigh);
+        if (*plow == (int64_t)-1) {
+            *plow = 0;
+            (*phigh)++;
+         } else {
+            (*plow)++;
+         }
+    }
+
+    if (sgn_divsr) {
+        divisor = 0 - divisor;
+    }
+
+    overflow = divu128((uint64_t *)plow, (uint64_t *)phigh, (uint64_t)divisor);
+
+    if (sgn_dvdnd  ^ sgn_divsr) {
+        *plow = 0 - *plow;
+    }
+
+    if (!overflow) {
+        if ((*plow < 0) ^ (sgn_dvdnd ^ sgn_divsr)) {
+            overflow = 1;
+        }
+    }
+
+    return overflow;
+}

 #endif
 #endif

+
+/**
+ * urshift - 128-bit Unsigned Right Shift.
+ * @plow: in/out - lower 64-bit integer.
+ * @phigh: in/out - higher 64-bit integer.
+ * @shift: in - bytes to shift, between 0 and 127.
+ *
+ * Result is zero-extended and stored in plow/phigh, which are
+ * input/output variables. Shift values outside the range will
+ * be mod to 128. In other words, the caller is responsible to
+ * verify/assert both the shift range and plow/phigh pointers.
+ */
+void urshift(uint64_t *plow, uint64_t *phigh, int32_t shift)
+{
+    shift &= 127;
+    if (shift == 0) {
+        return;
+    }
+
+    uint64_t h = *phigh >> (shift & 63);
+    if (shift >= 64) {
+        *plow = h;
+        *phigh = 0;
+    } else {
+        *plow = (*plow >> (shift & 63)) | (*phigh << (64 - (shift & 63)));
+        *phigh = h;
+    }

 }
 
 }
 

-/* Signed 64x64 -> 128 multiplication */
-void muls64 (uint64_t *plow, uint64_t *phigh, int64_t a, int64_t b)
+/**
+ * ulshift - 128-bit Unsigned Left Shift.
+ * @plow: in/out - lower 64-bit integer.
+ * @phigh: in/out - higher 64-bit integer.
+ * @shift: in - bytes to shift, between 0 and 127.
+ * @overflow: out - true if any 1-bit is shifted out.
+ *
+ * Result is zero-extended and stored in plow/phigh, which are
+ * input/output variables. Shift values outside the range will
+ * be mod to 128. In other words, the caller is responsible to
+ * verify/assert both the shift range and plow/phigh pointers.
+ */
+void ulshift(uint64_t *plow, uint64_t *phigh, int32_t shift, bool *overflow)

 {
 {

-    int sa, sb;
-
-    sa = (a < 0);
-    if (sa)
-        a = -a;
-    sb = (b < 0);
-    if (sb)
-        b = -b;
-    mul64(plow, phigh, a, b);
-    if (sa ^ sb) {
-        neg128(plow, phigh);
+    uint64_t low = *plow;
+    uint64_t high = *phigh;
+
+    shift &= 127;
+    if (shift == 0) {
+        return;
+    }
+
+    /* check if any bit will be shifted out */
+    urshift(&low, &high, 128 - shift);
+    if (low | high) {
+        *overflow = true;
+    }
+
+    if (shift >= 64) {
+        *phigh = *plow << (shift & 63);
+        *plow = 0;
+    } else {
+        *phigh = (*plow >> (64 - (shift & 63))) | (*phigh << (shift & 63));
+        *plow = *plow << shift;

     }
     }

-#if defined(DEBUG_MULDIV)
-    printf("muls64: 0x%016llx * 0x%016llx = 0x%016llx%016llx\n",
-           a, b, *phigh, *plow);
-#endif

 }
 }

-#endif /* !defined(__x86_64__) */