qemu/int128: add int128_urshift

Implement an unsigned right shift for Int128 values and add the same
tests cases of int128_rshift in the unit test.

Signed-off-by: Matheus Ferst <matheus.ferst@eldorado.org.br>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220330175932.6995-3-matheus.ferst@eldorado.org.br>
[danielhb: fixed long lines in test_urshift()]
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/include/qemu/int128.h b/include/qemu/int128.h
index 37e07fd6dd..1f82918c73 100644
--- a/include/qemu/int128.h
+++ b/include/qemu/int128.h
@@ -83,6 +83,11 @@ static inline Int128 int128_rshift(Int128 a, int n)
     return a >> n;
 }
 
+static inline Int128 int128_urshift(Int128 a, int n)
+{
+    return (__uint128_t)a >> n;
+}
+
 static inline Int128 int128_lshift(Int128 a, int n)
 {
     return a << n;
@@ -299,6 +304,20 @@ static inline Int128 int128_rshift(Int128 a, int n)
     }
 }
 
+static inline Int128 int128_urshift(Int128 a, int n)
+{
+    uint64_t h = a.hi;
+    if (!n) {
+        return a;
+    }
+    h = h >> (n & 63);
+    if (n >= 64) {
+        return int128_make64(h);
+    } else {
+        return int128_make128((a.lo >> n) | ((uint64_t)a.hi << (64 - n)), h);
+    }
+}
+
 static inline Int128 int128_lshift(Int128 a, int n)
 {
     uint64_t l = a.lo << (n & 63);