diff --git a/Changelog.txt b/Changelog.txt
index 2035dbce1..2b5dc3a94 100644
--- a/Changelog.txt
+++ b/Changelog.txt
@@ -19,7 +19,8 @@ common:
 	* Fixed #25 a wrong result of rotmg.
 
 x86/x86_64:
-	* 
+	* Fixed #28 a wrong result of dsdot on x86_64.
+
 MIPS64:
 	* 
 ====================================================================
diff --git a/kernel/Makefile.L1 b/kernel/Makefile.L1
index 317f14363..b08664a8e 100644
--- a/kernel/Makefile.L1
+++ b/kernel/Makefile.L1
@@ -668,7 +668,7 @@ $(KDIR)qdot_k$(TSUFFIX).$(SUFFIX) $(KDIR)qdot_k$(TPSUFFIX).$(PSUFFIX) : $(KERNEL
 	$(CC) -c $(CFLAGS) -UCOMPLEX -DXDOUBLE $< -o $@
 
 $(KDIR)dsdot_k$(TSUFFIX).$(SUFFIX) $(KDIR)dsdot_k$(TPSUFFIX).$(PSUFFIX) : $(KERNELDIR)/$(SDOTKERNEL) 
-	$(CC) -c $(CFLAGS) -UCOMPLEX -UDOUBLE $< -o $@
+	$(CC) -c $(CFLAGS) -UCOMPLEX -UDOUBLE -DDSDOT $< -o $@
 
 $(KDIR)sdot_k$(TSUFFIX).$(SUFFIX) $(KDIR)sdot_k$(TPSUFFIX).$(PSUFFIX) : $(KERNELDIR)/$(SDOTKERNEL) 
 	$(CC) -c $(CFLAGS) -UCOMPLEX -UDOUBLE $< -o $@
diff --git a/kernel/x86_64/dot_sse.S b/kernel/x86_64/dot_sse.S
index cc866a9c5..61c481064 100644
--- a/kernel/x86_64/dot_sse.S
+++ b/kernel/x86_64/dot_sse.S
@@ -1286,6 +1286,10 @@
 	haddps	%xmm0, %xmm0
 #endif
 
+#ifdef DSDOT
+	cvtss2sd %xmm0, %xmm0
+#endif
+
 	RESTOREREGISTERS
 
 	ret