diff mbox series

[PULL,02/44] host-utils: fix missing zero-extension in divs128

Message ID 20210930054426.357344-3-david@gibson.dropbear.id.au (mailing list archive)
State New, archived
Headers show
Series [PULL,01/44] host-utils: Fix overflow detection in divu128() | expand

Commit Message

David Gibson Sept. 30, 2021, 5:43 a.m. UTC 
From: Luis Pires <luis.pires@eldorado.org.br>

*plow (lower 64 bits of the dividend) is passed into divs128() as
a signed 64-bit integer. When building an __int128_t from it, it
must be zero-extended, instead of sign-extended.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Luis Pires <luis.pires@eldorado.org.br>
Message-Id: <20210910112624.72748-3-luis.pires@eldorado.org.br>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 include/qemu/host-utils.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h
index 711b221704..753b9fb89f 100644
--- a/include/qemu/host-utils.h
+++ b/include/qemu/host-utils.h
@@ -70,7 +70,7 @@  static inline int divs128(int64_t *plow, int64_t *phigh, int64_t divisor)
     if (divisor == 0) {
         return 1;
     } else {
-        __int128_t dividend = ((__int128_t)*phigh << 64) | *plow;
+        __int128_t dividend = ((__int128_t)*phigh << 64) | (uint64_t)*plow;
         __int128_t result = dividend / divisor;
         *plow = result;
         *phigh = dividend % divisor;