diff --git a/src/arch/x86/isa/decoder/two_byte_opcodes.isa b/src/arch/x86/isa/decoder/two_byte_opcodes.isa
index e1b20feb1..dfc328c4b 100644
--- a/src/arch/x86/isa/decoder/two_byte_opcodes.isa
+++ b/src/arch/x86/isa/decoder/two_byte_opcodes.isa
@@ -903,7 +903,7 @@
                 }
                 // operand size (0x66)
                 0x1: decode OPCODE_OP_BOTTOM3 {
-                    0x0: WarnUnimpl::addsubpd_Vo_Wo();
+                    0x0: ADDSUBPD(Vo,Wo);
                     0x1: PSRLW(Vo,Wo);
                     0x2: PSRLD(Vo,Wo);
                     0x3: PSRLQ(Vo,Wo);
diff --git a/src/arch/x86/isa/insts/simd128/floating_point/arithmetic/simultaneous_addition_and_subtraction.py b/src/arch/x86/isa/insts/simd128/floating_point/arithmetic/simultaneous_addition_and_subtraction.py
index 2e9aebfdc..00b191eca 100644
--- a/src/arch/x86/isa/insts/simd128/floating_point/arithmetic/simultaneous_addition_and_subtraction.py
+++ b/src/arch/x86/isa/insts/simd128/floating_point/arithmetic/simultaneous_addition_and_subtraction.py
@@ -37,5 +37,24 @@
 
 microcode = '''
 # ADDSUBPS
-# ADDSUBPD
+
+def macroop ADDSUBPD_XMM_XMM {
+    msubf xmml, xmml, xmmlm, size=8, ext=Scalar
+    maddf xmmh, xmmh, xmmhm, size=8, ext=Scalar
+};
+
+def macroop ADDSUBPD_XMM_M {
+    ldfp ufp1, seg, sib, disp, dataSize=8
+    ldfp ufp2, seg, sib, "DISPLACEMENT+8", dataSize=8
+    msubf xmmlm, xmml, ufp1, size=8, ext=0
+    maddf xmmhm, xmmh, ufp2, size=8, ext=0
+};
+
+def macroop ADDSUBPD_XMM_P {
+    rdip t7
+    ldfp ufp1, seg, sib, disp, dataSize=8
+    ldfp ufp2, seg, sib, "DISPLACEMENT+8", dataSize=8
+    msubf xmmlm, xmml, ufp1, size=8, ext=0
+    maddf xmmhm, xmmh, ufp2, size=8, ext=0
+};
 '''