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-rw-r--r--contrib/compiler-rt/lib/builtins/i386/floatdixf.S30
1 files changed, 30 insertions, 0 deletions
diff --git a/contrib/compiler-rt/lib/builtins/i386/floatdixf.S b/contrib/compiler-rt/lib/builtins/i386/floatdixf.S
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--- /dev/null
+++ b/contrib/compiler-rt/lib/builtins/i386/floatdixf.S
@@ -0,0 +1,30 @@
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+
+#include "../assembly.h"
+
+// float __floatdixf(di_int a);
+
+#ifdef __i386__
+
+// This routine has some extra memory traffic, loading the 64-bit input via two
+// 32-bit loads, then immediately storing it back to the stack via a single 64-bit
+// store. This is to avoid a write-small, read-large stall.
+// However, if callers of this routine can be safely assumed to store the argument
+// via a 64-bt store, this is unnecessary memory traffic, and should be avoided.
+// It can be turned off by defining the TRUST_CALLERS_USE_64_BIT_STORES macro.
+
+.text
+.balign 4
+DEFINE_COMPILERRT_FUNCTION(__floatdixf)
+#ifndef TRUST_CALLERS_USE_64_BIT_STORES
+ movd 4(%esp), %xmm0
+ movd 8(%esp), %xmm1
+ punpckldq %xmm1, %xmm0
+ movq %xmm0, 4(%esp)
+#endif
+ fildll 4(%esp)
+ ret
+END_COMPILERRT_FUNCTION(__floatdixf)
+
+#endif // __i386__