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[Qemu-devel] [PATCH v2 4/7] softfloat: fallback to __int128 maths for s3


From: Alex Bennée
Subject: [Qemu-devel] [PATCH v2 4/7] softfloat: fallback to __int128 maths for s390x and others
Date: Wed, 16 Jan 2019 20:23:46 +0000

Apparently some versions of clang can't handle inline assembly with
__int128 parameters, especially on s390. Instead of hand-coding the
s390 divide provide a generic fallback for anything that provides
__int128 capable maths.

Signed-off-by: Alex Bennée <address@hidden>
Cc: Thomas Huth <address@hidden>
---
 include/fpu/softfloat-macros.h | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/include/fpu/softfloat-macros.h b/include/fpu/softfloat-macros.h
index b1d772e6d4..1a43609eef 100644
--- a/include/fpu/softfloat-macros.h
+++ b/include/fpu/softfloat-macros.h
@@ -641,12 +641,6 @@ static inline uint64_t udiv_qrnnd(uint64_t *r, uint64_t n1,
     uint64_t q;
     asm("divq %4" : "=a"(q), "=d"(*r) : "0"(n0), "1"(n1), "rm"(d));
     return q;
-#elif defined(__s390x__)
-    /* Need to use a TImode type to get an even register pair for DLGR.  */
-    unsigned __int128 n = (unsigned __int128)n1 << 64 | n0;
-    asm("dlgr %0, %1" : "+r"(n) : "r"(d));
-    *r = n >> 64;
-    return n;
 #elif defined(_ARCH_PPC64) && defined(_ARCH_PWR7)
     /* From Power ISA 2.06, programming note for divdeu.  */
     uint64_t q1, q2, Q, r1, r2, R;
@@ -663,6 +657,10 @@ static inline uint64_t udiv_qrnnd(uint64_t *r, uint64_t n1,
     }
     *r = R;
     return Q;
+#elif defined(CONFIG_INT128)
+    unsigned __int128 n = (unsigned __int128)n1 << 64 | n0;
+    *r = n % d;
+    return n / d;
 #else
     uint64_t d0, d1, q0, q1, r1, r0, m;
 
-- 
2.17.1




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