diff --git a/src/arch/x86/utility.cc b/src/arch/x86/utility.cc
--- a/src/arch/x86/utility.cc
+++ b/src/arch/x86/utility.cc
@@ -354,17 +354,17 @@
 double
 loadFloat80(const void *_mem)
 {
-    const fp80_t *fp80((const fp80_t *)_mem);
+    fp80_t fp80;
+    memcpy(fp80.bits, _mem, 10);
 
-    return fp80_cvtd(*fp80);
+    return fp80_cvtd(fp80);
 }
 
 void
 storeFloat80(void *_mem, double value)
 {
-    fp80_t *fp80((fp80_t *)_mem);
-
-    *fp80 = fp80_cvfd(value);
+    fp80_t fp80 = fp80_cvfd(value);
+    memcpy(_mem, fp80.bits, 10);
 }
 
 } // namespace X86_ISA
# Node ID c211fc37d7a16c53baa4b77995ec73eaaa718c48
# Parent  c638b7be766b0f73c9a4daf7b11973eaad1e698d
diff --git a/ext/fputils/fpbits.h b/ext/fputils/fpbits.h
--- a/ext/fputils/fpbits.h
+++ b/ext/fputils/fpbits.h
@@ -84,6 +84,7 @@
 
 #define BUILD_FP80(sign, frac, exp)                             \
     {                                                           \
+        .repr.pad = { 0 },                                          \
         .repr.se = BUILD_FP80_SE(sign, exp),                    \
         .repr.fi = BUILD_FP80_FI(frac, exp)                     \
     }
diff --git a/ext/fputils/include/fputils/fptypes.h b/ext/fputils/include/fputils/fptypes.h
--- a/ext/fputils/include/fputils/fptypes.h
+++ b/ext/fputils/include/fputils/fptypes.h
@@ -69,12 +69,16 @@
         uint64_t fi;
         /** Raw representation of sign bit and exponent */
         uint16_t se;
+        /** Add explicit padding to ensure this data structure
+         * is properly aligned.
+         */
+        uint16_t pad[3];
     } repr;
     /**
      * Represented as a char array, mainly intended for debug dumping
      * and serialization.
      */
-    char bits[10];
+    char bits[16];
 } fp80_t;
 
 /** @} */
diff --git a/src/arch/x86/isa/microops/fpop.isa b/src/arch/x86/isa/microops/fpop.isa
--- a/src/arch/x86/isa/microops/fpop.isa
+++ b/src/arch/x86/isa/microops/fpop.isa
@@ -342,7 +342,7 @@
     # extract the highest 64 bits.
     class cvtfp80h_int(ConvOp):
         code = '''
-            char bits[10];
+            uint8_t bits[10];
             storeFloat80(bits, FpSrcReg1);
             SDestReg = *(uint64_t *)(bits + 0);
             '''
@@ -351,7 +351,7 @@
     # extract the lowest 16 bits.
     class cvtfp80l_int(ConvOp):
         code = '''
-            char bits[10];
+            uint8_t bits[10];
             storeFloat80(bits, FpSrcReg1);
             SDestReg = *(uint16_t *)(bits + 8);
             '''