diff -r bdd606534bdc src/arch/mips/isa/decoder.isa
--- a/src/arch/mips/isa/decoder.isa	Tue Dec 03 10:51:40 2013 -0600
+++ b/src/arch/mips/isa/decoder.isa	Wed Dec 11 23:02:58 2013 -0500
@@ -1242,8 +1242,8 @@
                     //Field When rs=W
                     0x4: decode FUNCTION {
                         format FloatConvertOp {
-                            0x20: cvt_s_w({{ val = Fs_uw; }}, ToSingle);
-                            0x21: cvt_d_w({{ val = Fs_uw; }}, ToDouble);
+                            0x20: cvt_s_w({{ val = Fs_sw; }}, ToSingle);
+                            0x21: cvt_d_w({{ val = Fs_sw; }}, ToDouble);
                             0x26: CP1Unimpl::cvt_ps_w();
                         }
                         default: CP1Unimpl::unknown();
@@ -1255,8 +1255,8 @@
                     //floating point operations are enabled."
                     0x5: decode FUNCTION {
                         format FloatConvertOp {
-                            0x20: cvt_s_l({{ val = Fs_ud; }}, ToSingle);
-                            0x21: cvt_d_l({{ val = Fs_ud; }}, ToDouble);
+                            0x20: cvt_s_l({{ val = Fs_sd; }}, ToSingle);
+                            0x21: cvt_d_l({{ val = Fs_sd; }}, ToDouble);
                             0x26: CP1Unimpl::cvt_ps_l();
                         }
                         default: CP1Unimpl::unknown();
diff -r bdd606534bdc src/arch/mips/isa/formats/fp.isa
--- a/src/arch/mips/isa/formats/fp.isa	Tue Dec 03 10:51:40 2013 -0600
+++ b/src/arch/mips/isa/formats/fp.isa	Wed Dec 11 23:02:58 2013 -0500
@@ -268,11 +268,11 @@
     elif '_df' in code:
         code = 'double ' + code + '\n'
         convert += 'DOUBLE_TO_'
-    elif '_uw' in code:
-        code = 'uint32_t ' + code + '\n'
+    elif '_sw' in code:
+        code = 'int32_t ' + code + '\n'
         convert += 'WORD_TO_'
-    elif '_ud' in code:
-        code = 'uint64_t ' + code + '\n'
+    elif '_sd' in code:
+        code = 'int64_t ' + code + '\n'
         convert += 'LONG_TO_'
     else:
         sys.exit("Error Determining Source Type for Conversion")