Fix 32-bit segment-register MOVs (they write 32 bits to a register, but only 16 bits to memory)

modules/pcjs/lib/x86func.js

@@ -1702,6 +1702,14 @@ X86.fnMOVn = function MOVn(dst, src)
  */
 X86.fnMOVxx = function MOVxx(dst, src)
 {
+    if (this.regEAWrite !== X86.ADDR_INVALID) {
+        /*
+         * When a 32-bit OPERAND size is in effect, opMOVwsr() will write 32 bits (zero-extended) if the destination
+         * is a register, but only 16 bits if the destination is memory.  The only other caller, opMOVrc(), is not
+         * affected, because it writes only to register destinations.
+         */
+        this.setDataSize(2);
+    }
     return X86.fnMOV.call(this, dst, this.regXX);
 };
 

modules/pcjs/lib/x86ops.js

@@ -2098,10 +2098,6 @@ X86.opMOVwsr = function MOVwsr()
     }
     /*
      * Like other MOV operations, the destination does not need to be read, just written.
-     *
-     * TODO: Confirm this instruction's behavior on the 80386; ie, if a 32-bit OPERAND size is
-     * in effect, does it still write only 16 bits? If so, we must add a setDataSize(2) override.
-     * Confirm for both register and memory destinations.
      */
     this.opFlags |= X86.OPFLAG.NOREAD;
     this.aOpModMemWord[bModRM].call(this, X86.fnMOVxx);