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[PATCH v3 02/22] host-utils: fix missing zero-extension in divs128


From: Luis Pires
Subject: [PATCH v3 02/22] host-utils: fix missing zero-extension in divs128
Date: Fri, 10 Sep 2021 08:26:04 -0300

*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>
---
 include/qemu/host-utils.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

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;
-- 
2.25.1




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