diff --git a/Changes b/Changes
index bda43c901..36d045c6d 100644
--- a/Changes
+++ b/Changes
@@ -10,6 +10,8 @@ The contributors that suggested a given feature are shown in []. Thanks!
 
 ***   Support assert properties, bug785, bug1290. [John Coiner, et al]
 
+***   Support $writememh. [John Coiner]
+
 ***   Add --no-debug-leak to reduce memory use under debug. [John Coiner]
 
 ****  On convergence errors, show activity. [John Coiner]
diff --git a/include/verilated.cpp b/include/verilated.cpp
index fda1c1a3a..172197598 100644
--- a/include/verilated.cpp
+++ b/include/verilated.cpp
@@ -1205,10 +1205,134 @@ IData VL_SSCANF_INX(int, const std::string& ld, const char* formatp, ...) VL_MT_
     return got;
 }
 
+void VL_WRITEMEM_Q(bool hex, int width, int depth, int array_lsb, int,
+                   QData ofilename, const void* memp, IData start,
+                   IData end) VL_MT_SAFE {
+    WData fnw[2];  VL_SET_WQ(fnw, ofilename);
+    return VL_WRITEMEM_W(hex, width,depth,array_lsb,2,fnw,memp,start,end);
+}
+
+void VL_WRITEMEM_W(bool hex, int width, int depth, int array_lsb, int fnwords,
+                   WDataInP ofilenamep, const void* memp, IData start,
+                   IData end) VL_MT_SAFE {
+    char ofilenamez[VL_TO_STRING_MAX_WORDS*VL_WORDSIZE+1];
+    _VL_VINT_TO_STRING(fnwords*VL_WORDSIZE, ofilenamez, ofilenamep);
+    std::string ofilenames(ofilenamez);
+    return VL_WRITEMEM_N(hex, width,depth,array_lsb,ofilenames,memp,start,end);
+}
+
+const char* memhFormat(int nBits) {
+    assert((nBits >= 1) && (nBits <= 32));
+
+    static char buf[32];
+    switch ((nBits - 1) / 4) {
+    case 0: VL_SNPRINTF(buf, 32, "%%01x"); break;
+    case 1: VL_SNPRINTF(buf, 32, "%%02x"); break;
+    case 2: VL_SNPRINTF(buf, 32, "%%03x"); break;
+    case 3: VL_SNPRINTF(buf, 32, "%%04x"); break;
+    case 4: VL_SNPRINTF(buf, 32, "%%05x"); break;
+    case 5: VL_SNPRINTF(buf, 32, "%%06x"); break;
+    case 6: VL_SNPRINTF(buf, 32, "%%07x"); break;
+    case 7: VL_SNPRINTF(buf, 32, "%%08x"); break;
+    default: assert(false); break;
+    }
+    return buf;
+}
+
+void VL_WRITEMEM_N(
+    bool      hex,  // Hex format, else binary
+    int     width,  // Width of each array row
+    int     depth,  // Number of rows
+    int array_lsb,  // Index of first row. Valid row addresses
+    //              //  range from array_lsb up to (array_lsb + depth - 1)
+    const std::string& ofilenamep,  // Output file name
+    const void* memp,  // Array state
+    IData   start,  // First array row address to write
+    IData     end   // Last address to write
+    ) VL_MT_SAFE {
+    if (VL_UNLIKELY(!hex)) {
+        VL_FATAL_MT(ofilenamep.c_str(), 0, "",
+                    "VL_WRITEMEM_N only supports hex format for now, sorry!");
+        return;
+    }
+    FILE* fp = fopen(ofilenamep.c_str(), "w");
+    if (VL_UNLIKELY(!fp)) {
+        VL_FATAL_MT(ofilenamep.c_str(), 0, "", "$writemem file not found");
+        return;
+    }
+
+    for (int row_addr = start; row_addr <= end; ++row_addr) {
+        if ((row_addr < array_lsb)
+            || (row_addr > array_lsb + depth - 1)) {
+            vluint32_t endmax = ~0;
+            if (end != endmax) {
+                VL_FATAL_MT(ofilenamep.c_str(), 0, "",
+                            "$writemem specified address out-of-bounds");
+            }
+            // else, it's not an error to overflow due to end == endmax,
+            // just return cleanly.
+            goto cleanup;
+        }
+
+        // Compute the offset into the memp array.
+        int row_offset = row_addr - array_lsb;
+
+        if (width <= 8) {
+            const CData* datap
+                = &(reinterpret_cast<const CData*>(memp))[row_offset];
+            fprintf(fp, memhFormat(width), VL_MASK_I(width) & *datap);
+            fprintf(fp, "\n");
+        } else if (width <= 16) {
+            const SData* datap
+                = &(reinterpret_cast<const SData*>(memp))[row_offset];
+            fprintf(fp, memhFormat(width), VL_MASK_I(width) & *datap);
+            fprintf(fp, "\n");
+        } else if (width <= 32) {
+            const IData* datap
+                = &(reinterpret_cast<const IData*>(memp))[row_offset];
+            fprintf(fp, memhFormat(width), VL_MASK_I(width) & *datap);
+            fprintf(fp, "\n");
+        } else if (width <= 64) {
+            const QData* datap
+                = &(reinterpret_cast<const QData*>(memp))[row_offset];
+            vluint64_t value = VL_MASK_Q(width) & *datap;
+            vluint32_t lo = value & 0xffffffff;
+            vluint32_t hi = value >> 32;
+            fprintf(fp, memhFormat(width - 32), hi);
+            fprintf(fp, "%08x\n", lo);
+        } else {
+            WDataInP memDatap = reinterpret_cast<WDataInP>(memp);
+            WDataInP datap = &memDatap[row_offset * VL_WORDS_I(width)];
+            // output as a sequence of VL_WORDSIZE'd words
+            // from MSB to LSB. Mask off the MSB word which could
+            // contain junk above the top of valid data.
+            int word_idx = ((width - 1) / VL_WORDSIZE);
+            bool first = true;
+            while (word_idx >= 0) {
+                IData data = datap[word_idx];
+                if (first) {
+                    data &= VL_MASK_I(width);
+                    int top_word_nbits = ((width - 1) & 0x1f) + 1;
+                    fprintf(fp, memhFormat(top_word_nbits), data);
+                } else {
+                    fprintf(fp, "%08x", data);
+                }
+
+                word_idx--;
+                first = false;
+            }
+            fprintf(fp, "\n");
+        }
+    }
+
+  cleanup:
+    fclose(fp);
+}
+
 void VL_READMEM_Q(bool hex, int width, int depth, int array_lsb, int,
 		  QData ofilename, void* memp, IData start, IData end) VL_MT_SAFE {
     WData fnw[2];  VL_SET_WQ(fnw, ofilename);
-    return VL_READMEM_W(hex,width,depth,array_lsb,2, fnw,memp,start,end);
+    return VL_READMEM_W(hex,width,depth,array_lsb,2,fnw,memp,start,end);
 }
 
 void VL_READMEM_W(bool hex, int width, int depth, int array_lsb, int fnwords,
@@ -1216,12 +1340,20 @@ void VL_READMEM_W(bool hex, int width, int depth, int array_lsb, int fnwords,
     char ofilenamez[VL_TO_STRING_MAX_WORDS*VL_WORDSIZE+1];
     _VL_VINT_TO_STRING(fnwords*VL_WORDSIZE, ofilenamez, ofilenamep);
     std::string ofilenames(ofilenamez);
-    return VL_READMEM_N(hex,width,depth,array_lsb,fnwords,ofilenames,memp,start,end);
+    return VL_READMEM_N(hex,width,depth,array_lsb,ofilenames,memp,start,end);
 }
 
-void VL_READMEM_N(bool hex, int width, int depth, int array_lsb, int fnwords,
-		  const std::string& ofilenamep, void* memp, IData start, IData end) VL_MT_SAFE {
-    if (fnwords) {}
+void VL_READMEM_N(
+    bool      hex,  // Hex format, else binary
+    int     width,  // Width of each array row
+    int     depth,  // Number of rows
+    int array_lsb,  // Index of first row. Valid row addresses
+    //              //  range from array_lsb up to (array_lsb + depth - 1)
+    const std::string& ofilenamep,  // Input file name
+    void*    memp,  // Array state
+    IData   start,  // First array row address to read
+    IData     end   // Last row address to read
+    ) VL_MT_SAFE {
     FILE* fp = fopen(ofilenamep.c_str(), "r");
     if (VL_UNLIKELY(!fp)) {
         // We don't report the Verilog source filename as it slow to have to pass it down
diff --git a/include/verilated.h b/include/verilated.h
index 7fb5220b5..ef3a7fd13 100644
--- a/include/verilated.h
+++ b/include/verilated.h
@@ -549,6 +549,14 @@ inline void VL_READMEM_I(bool hex, int width, int depth, int array_lsb, int fnwo
 			 IData ofilename,    void* memp, IData start, IData end) VL_MT_SAFE {
     VL_READMEM_Q(hex, width,depth,array_lsb,fnwords, ofilename,memp,start,end); }
 
+extern void VL_WRITEMEM_W(bool hex, int width, int depth, int array_lsb, int fnwords,
+                          WDataInP ofilename, const void* memp, IData start, IData end);
+extern void VL_WRITEMEM_Q(bool hex, int width, int depth, int array_lsb, int fnwords,
+                          QData ofilename,    const void* memp, IData start, IData end);
+inline void VL_WRITEMEM_I(bool hex, int width, int depth, int array_lsb, int fnwords,
+                          IData ofilename,    const void* memp, IData start, IData end) VL_MT_SAFE {
+    VL_WRITEMEM_Q(hex, width,depth,array_lsb,fnwords, ofilename,memp,start,end); }
+
 extern void VL_WRITEF(const char* formatp, ...);
 extern void VL_FWRITEF(IData fpi, const char* formatp, ...);
 
diff --git a/include/verilated_heavy.h b/include/verilated_heavy.h
index aed7683c7..77515849f 100644
--- a/include/verilated_heavy.h
+++ b/include/verilated_heavy.h
@@ -64,8 +64,12 @@ inline std::string VL_REPLICATEN_NNI(int obits,int lbits,int rbits,
 inline IData VL_LEN_IN(const std::string& ld) { return ld.length(); }
 
 extern IData VL_FOPEN_NI(const std::string& filename, IData mode) VL_MT_SAFE;
-extern void VL_READMEM_N(bool hex, int width, int depth, int array_lsb, int fnwords,
-                         const std::string& ofilename, void* memp, IData start, IData end) VL_MT_SAFE;
+extern void VL_READMEM_N(bool hex, int width, int depth, int array_lsb,
+                         const std::string& ofilename,
+                         void* memp, IData start, IData end) VL_MT_SAFE;
+extern void VL_WRITEMEM_N(bool hex, int width, int depth, int array_lsb,
+                          const std::string& ofilename,
+                          const void* memp, IData start, IData end) VL_MT_SAFE;
 extern IData VL_SSCANF_INX(int lbits, const std::string& ld, const char* formatp, ...) VL_MT_SAFE;
 extern void VL_SFORMAT_X(int obits_ignored, std::string& output, const char* formatp, ...) VL_MT_SAFE;
 extern std::string VL_SFORMATF_NX(const char* formatp, ...) VL_MT_SAFE;
diff --git a/src/V3AstNodes.h b/src/V3AstNodes.h
index c6b19f6f7..cffc5d07b 100644
--- a/src/V3AstNodes.h
+++ b/src/V3AstNodes.h
@@ -2773,17 +2773,16 @@ public:
     void 	fromp(AstNode* nodep) { setOp2p(nodep); }
 };
 
-class AstReadMem : public AstNodeStmt {
+class AstNodeReadWriteMem : public AstNodeStmt {
 private:
     bool	m_isHex;	// readmemh, not readmemb
 public:
-    AstReadMem(FileLine* fileline, bool hex,
-	       AstNode* filenamep, AstNode* memp, AstNode* lsbp, AstNode* msbp)
+    AstNodeReadWriteMem(FileLine* fileline, bool hex,
+                        AstNode* filenamep, AstNode* memp,
+                        AstNode* lsbp, AstNode* msbp)
 	: AstNodeStmt (fileline), m_isHex(hex) {
 	setOp1p(filenamep); setOp2p(memp); setNOp3p(lsbp); setNOp4p(msbp);
     }
-    ASTNODE_NODE_FUNCS(ReadMem)
-    virtual string verilogKwd() const { return (isHex()?"$readmemh":"$readmemb"); }
     virtual bool isGateOptimizable() const { return false; }
     virtual bool isPredictOptimizable() const { return false; }
     virtual bool isPure() const { return false; }
@@ -2791,12 +2790,35 @@ public:
     virtual bool isUnlikely() const { return true; }
     virtual V3Hash sameHash() const { return V3Hash(); }
     virtual bool same(const AstNode* samep) const {
-	return isHex()==static_cast<const AstReadMem*>(samep)->isHex(); }
+	return isHex()==static_cast<const AstNodeReadWriteMem*>(samep)->isHex();
+    }
     bool	isHex() const { return m_isHex; }
     AstNode*	filenamep() const { return op1p(); }
     AstNode*	memp() const { return op2p(); }
     AstNode*	lsbp() const { return op3p(); }
     AstNode*	msbp() const { return op4p(); }
+    virtual const char* cFuncPrefixp() const = 0;
+};
+
+class AstReadMem : public AstNodeReadWriteMem {
+public:
+    AstReadMem(FileLine* fileline, bool hex,
+	       AstNode* filenamep, AstNode* memp, AstNode* lsbp, AstNode* msbp)
+	: AstNodeReadWriteMem(fileline, hex, filenamep, memp, lsbp, msbp)
+        { }
+    ASTNODE_NODE_FUNCS(ReadMem);
+    virtual string verilogKwd() const { return (isHex()?"$readmemh":"$readmemb"); }
+    virtual const char* cFuncPrefixp() const { return "VL_READMEM_"; }
+};
+
+class AstWriteMem : public AstNodeReadWriteMem {
+public:
+    AstWriteMem(FileLine* fileline,
+                AstNode* filenamep, AstNode* memp, AstNode* lsbp, AstNode* msbp)
+	: AstNodeReadWriteMem(fileline, true, filenamep, memp, lsbp, msbp) { }
+    ASTNODE_NODE_FUNCS(WriteMem)
+    virtual string verilogKwd() const { return (isHex()?"$writememh":"$writememb"); }
+    virtual const char* cFuncPrefixp() const { return "VL_WRITEMEM_"; }
 };
 
 class AstSystemT : public AstNodeStmt {
diff --git a/src/V3EmitC.cpp b/src/V3EmitC.cpp
index 9ee1e6239..a048ea89e 100644
--- a/src/V3EmitC.cpp
+++ b/src/V3EmitC.cpp
@@ -322,8 +322,8 @@ public:
 	nodep->modep()->iterateAndNext(*this);
 	puts(");\n");
     }
-    virtual void visit(AstReadMem* nodep) {
-	puts("VL_READMEM_");
+    virtual void visit(AstNodeReadWriteMem* nodep) {
+        puts(nodep->cFuncPrefixp());
 	emitIQW(nodep->filenamep());
 	puts(" (");  // We take a void* rather than emitIQW(nodep->memp());
 	puts(nodep->isHex()?"true":"false");
@@ -333,21 +333,26 @@ public:
 	uint32_t array_lsb = 0;
 	{
 	    AstVarRef* varrefp = nodep->memp()->castVarRef();
-	    if (!varrefp) { nodep->v3error("Readmem loading non-variable"); }
+            if (!varrefp) {
+                nodep->v3error(nodep->verilogKwd() << " loading non-variable");
+            }
 	    else if (AstUnpackArrayDType* adtypep = varrefp->varp()->dtypeSkipRefp()->castUnpackArrayDType()) {
 		puts(cvtToStr(varrefp->varp()->dtypep()->arrayUnpackedElements()));
 		array_lsb = adtypep->lsb();
 	    }
 	    else {
-		nodep->v3error("Readmem loading other than unpacked-array variable");
+		nodep->v3error(nodep->verilogKwd()
+                               << " loading other than unpacked-array variable");
 	    }
 	}
 	putbs(", ");
 	puts(cvtToStr(array_lsb));
 	putbs(",");
-	puts(cvtToStr(nodep->filenamep()->widthWords()));
-	checkMaxWords(nodep->filenamep());
-	putbs(", ");
+        if (!nodep->filenamep()->dtypep()->isString()) {
+            puts(cvtToStr(nodep->filenamep()->widthWords()));
+            checkMaxWords(nodep->filenamep());
+            putbs(", ");
+        }
 	nodep->filenamep()->iterateAndNext(*this);
 	putbs(", ");
 	nodep->memp()->iterateAndNext(*this);
diff --git a/src/V3EmitV.cpp b/src/V3EmitV.cpp
index 117eac41d..4b257f1b7 100644
--- a/src/V3EmitV.cpp
+++ b/src/V3EmitV.cpp
@@ -268,7 +268,7 @@ class EmitVBaseVisitor : public EmitCBaseVisitor {
 	if (nodep->stmtsp()) nodep->stmtsp()->iterateAndNext(*this);
 	puts("end\n");
     }
-    virtual void visit(AstReadMem* nodep) {
+    virtual void visit(AstNodeReadWriteMem* nodep) {
 	putfs(nodep,nodep->verilogKwd());
 	putbs(" (");
 	if (nodep->filenamep()) nodep->filenamep()->iterateAndNext(*this);
diff --git a/src/V3Width.cpp b/src/V3Width.cpp
index 522ca4b48..5a2227965 100644
--- a/src/V3Width.cpp
+++ b/src/V3Width.cpp
@@ -2204,12 +2204,13 @@ private:
 	assertAtStatement(nodep);
 	userIterateAndNext(nodep->lhsp(), WidthVP(SELF,BOTH).p());
     }
-    virtual void visit(AstReadMem* nodep) {
+    virtual void visit(AstNodeReadWriteMem* nodep) {
 	assertAtStatement(nodep);
 	userIterateAndNext(nodep->filenamep(), WidthVP(SELF,BOTH).p());
 	userIterateAndNext(nodep->memp(), WidthVP(SELF,BOTH).p());
 	if (!nodep->memp()->dtypep()->skipRefp()->castUnpackArrayDType()) {
-	    nodep->memp()->v3error("Unsupported: $readmem into other than unpacked array");
+	    nodep->memp()->v3error("Unsupported: " << nodep->verilogKwd()
+                                   << " into other than unpacked array");
 	}
 	userIterateAndNext(nodep->lsbp(), WidthVP(SELF,BOTH).p());
 	userIterateAndNext(nodep->msbp(), WidthVP(SELF,BOTH).p());
diff --git a/src/verilog.l b/src/verilog.l
index 67a423332..dc2ff7fca 100644
--- a/src/verilog.l
+++ b/src/verilog.l
@@ -269,6 +269,7 @@ vnum	{vnum1}|{vnum2}|{vnum3}|{vnum4}|{vnum5}
   "$value$plusargs"	{ FL; return yD_VALUEPLUSARGS; }
   "$width"		{ FL; return yaTIMINGSPEC; }
   "$write"		{ FL; return yD_WRITE; }
+  "$writememh"		{ FL; return yD_WRITEMEMH; }
   /*     Keywords */
   "always"		{ FL; return yALWAYS; }
   "and"			{ FL; return yAND; }
diff --git a/src/verilog.y b/src/verilog.y
index 8bf478df9..3b76f6fdc 100644
--- a/src/verilog.y
+++ b/src/verilog.y
@@ -515,6 +515,7 @@ class AstSenTree;
 %token<fl>		yD_VALUEPLUSARGS "$value$plusargs"
 %token<fl>		yD_WARNING	"$warning"
 %token<fl>		yD_WRITE	"$write"
+%token<fl>		yD_WRITEMEMH	"$writememh"
 
 %token<fl>		yVL_CLOCK		"/*verilator sc_clock*/"
 %token<fl>		yVL_CLOCKER		"/*verilator clocker*/"
@@ -2700,6 +2701,10 @@ system_t_call<nodep>:		// IEEE: system_tf_call (as task)
 	|	yD_READMEMH '(' expr ',' idClassSel ',' expr ')'		{ $$ = new AstReadMem($1,true, $3,$5,$7,NULL); }
 	|	yD_READMEMH '(' expr ',' idClassSel ',' expr ',' expr ')'	{ $$ = new AstReadMem($1,true, $3,$5,$7,$9); }
 	//
+	|	yD_WRITEMEMH '(' expr ',' idClassSel ')'			{ $$ = new AstWriteMem($1,$3,$5,NULL,NULL); }
+	|	yD_WRITEMEMH '(' expr ',' idClassSel ',' expr ')'		{ $$ = new AstWriteMem($1,$3,$5,$7,NULL); }
+	|	yD_WRITEMEMH '(' expr ',' idClassSel ',' expr ',' expr ')'	{ $$ = new AstWriteMem($1,$3,$5,$7,$9); }
+	//
 	// Any system function as a task
 	|	system_f_call_or_t			{ $$ = new AstSysFuncAsTask($<fl>1, $1); }
 	;
diff --git a/test_regress/t/t_sys_readmem.v b/test_regress/t/t_sys_readmem.v
index 1f0f58be9..66d1a7936 100644
--- a/test_regress/t/t_sys_readmem.v
+++ b/test_regress/t/t_sys_readmem.v
@@ -10,14 +10,59 @@ module t;
    reg [5:0] binary_nostart [2:15];
    reg [5:0] binary_start [0:15];
    reg [175:0] hex [0:15];
+   reg [(32*6)-1:0] hex_align [0:15];
+   string fns;
+
+`ifdef WRITEMEM_READ_BACK
+   reg [5:0] binary_string_tmp [2:15];
+   reg [5:0] binary_nostart_tmp [2:15];
+   reg [5:0] binary_start_tmp [0:15];
+   reg [175:0] hex_tmp [0:15];
+   reg [(32*6)-1:0] hex_align_tmp [0:15];
+   string fns_tmp;
+`endif
    // verilator lint_on LITENDIAN
 
    integer   i;
 
    initial begin
+      begin
+         // Initialize memories to zero,
+         // avoid differences between 2-state and 4-state.
+         for (i=0; i<16; i=i+1) begin
+            binary_start[i] = 6'h0;
+            hex[i] = 176'h0;
+            hex_align[i] = {32*6{1'b0}};
+`ifdef WRITEMEM_READ_BACK
+            binary_start_tmp[i] = 6'h0;
+            hex_tmp[i] = 176'h0;
+            hex_align_tmp[i] = {32*6{1'b0}};
+`endif
+         end
+         for (i=2; i<16; i=i+1) begin
+            binary_string[i] = 6'h0;
+            binary_nostart[i] = 6'h0;
+`ifdef WRITEMEM_READ_BACK
+            binary_string_tmp[i] = 6'h0;
+            binary_nostart_tmp[i] = 6'h0;
+`endif
+         end
+      end
 
       begin
+`ifdef WRITEMEM_READ_BACK
+         $readmemb("t/t_sys_readmem_b.mem", binary_nostart_tmp);
+         // Do a round-trip $writememh and $readmemh cycle.
+         // This covers $writememh and ensures we can read our
+         // own memh output file.
+ `ifdef TEST_VERBOSE
+         $display("-Writing %s", `OUT_TMP1);
+ `endif
+         $writememh(`OUT_TMP1, binary_nostart_tmp);
+         $readmemh(`OUT_TMP1, binary_nostart);
+`else
 	 $readmemb("t/t_sys_readmem_b.mem", binary_nostart);
+`endif
 `ifdef TEST_VERBOSE
 	 for (i=0; i<16; i=i+1) $write("    @%x = %x\n", i, binary_nostart[i]);
 `endif
@@ -33,7 +78,16 @@ module t;
       end
 
       begin
+`ifdef WRITEMEM_READ_BACK
+         $readmemb("t/t_sys_readmem_b_8.mem", binary_start_tmp, 4, 4+7);
+ `ifdef TEST_VERBOSE
+         $display("-Writing %s", `OUT_TMP2);
+ `endif
+         $writememh(`OUT_TMP2, binary_start_tmp, 4, 4+7);
+         $readmemh(`OUT_TMP2, binary_start, 4, 4+7);
+`else
 	 $readmemb("t/t_sys_readmem_b_8.mem", binary_start, 4, 4+7);
+`endif
 `ifdef TEST_VERBOSE
 	 for (i=0; i<16; i=i+1) $write("    @%x = %x\n", i, binary_start[i]);
 `endif
@@ -48,7 +102,18 @@ module t;
       end
 
       begin
+         // The 'hex' array is a non-exact multiple of word size
+         // (possible corner case)
+`ifdef WRITEMEM_READ_BACK
+         $readmemh("t/t_sys_readmem_h.mem", hex_tmp, 0);
+ `ifdef TEST_VERBOSE
+         $display("-Writing %s", `OUT_TMP3);
+ `endif
+         $writememh(`OUT_TMP3, hex_tmp, 0);
+         $readmemh(`OUT_TMP3, hex, 0);
+`else
 	 $readmemh("t/t_sys_readmem_h.mem", hex, 0);
+`endif
 `ifdef TEST_VERBOSE
 	 for (i=0; i<16; i=i+1) $write("    @%x = %x\n", i, hex[i]);
 `endif
@@ -59,8 +124,40 @@ module t;
       end
 
       begin
-	 string fns = "t/t_sys_readmem_b.mem";
+         // The 'hex align' array is similar to 'hex', but it is an
+         // exact multiple of word size -- another possible corner case.
+`ifdef WRITEMEM_READ_BACK
+         $readmemh("t/t_sys_readmem_align_h.mem", hex_align_tmp, 0);
+ `ifdef TEST_VERBOSE
+         $display("-Writing %s", `OUT_TMP4);
+ `endif
+         $writememh(`OUT_TMP4, hex_align_tmp, 0);
+         $readmemh(`OUT_TMP4, hex_align, 0);
+`else
+	 $readmemh("t/t_sys_readmem_align_h.mem", hex_align, 0);
+`endif
+`ifdef TEST_VERBOSE
+	 for (i=0; i<16; i=i+1) $write("    @%x = %x\n", i, hex_align[i]);
+`endif
+	 if (hex_align['h04] != 192'h77554004_37654321_27654321_17654321_07654321_abcdef10) $stop;
+	 if (hex_align['h0a] != 192'h7755400a_37654321_27654321_17654321_07654321_abcdef11) $stop;
+	 if (hex_align['h0b] != 192'h7755400b_37654321_27654321_17654321_07654321_abcdef12) $stop;
+	 if (hex_align['h0c] != 192'h7755400c_37654321_27654321_17654321_07654321_abcdef13) $stop;
+      end
+
+      begin
+         fns = "t/t_sys_readmem_b.mem";
+`ifdef WRITEMEM_READ_BACK
+         fns_tmp = `OUT_TMP5;
+         $readmemb(fns, binary_string_tmp);
+ `ifdef TEST_VERBOSE
+         $display("-Writing %s", `OUT_TMP5);
+ `endif
+         $writememh(fns_tmp, binary_string_tmp);
+         $readmemh(fns_tmp, binary_string);
+`else
 	 $readmemb(fns, binary_string);
+`endif
 `ifdef TEST_VERBOSE
 	 for (i=0; i<16; i=i+1) $write("    @%x = %x\n", i, binary_string[i]);
 `endif
diff --git a/test_regress/t/t_sys_readmem_align_h.mem b/test_regress/t/t_sys_readmem_align_h.mem
new file mode 100644
index 000000000..b23a4b92b
--- /dev/null
+++ b/test_regress/t/t_sys_readmem_align_h.mem
@@ -0,0 +1,13 @@
+// DESCRIPTION: Verilator: Verilog Test data file
+//
+// Copyright 2006 by Wilson Snyder. This program is free software; you can
+// redistribute it and/or modify it under the terms of either the GNU
+// Lesser General Public License Version 3 or the Perl Artistic License
+// Version 2.0.
+
+@4
+77554004_37654321_27654321_17654321_07654321_abcdef10
+@a
+7755400a_37654321_27654321_17654321_07654321_abcdef11
+7755400b_37654321_27654321_17654321_07654321_abcdef12
+7755400c_37654321_27654321_17654321_07654321_abcdef13
diff --git a/test_regress/t/t_sys_writemem.gold1.mem b/test_regress/t/t_sys_writemem.gold1.mem
new file mode 100644
index 000000000..b25ae23ef
--- /dev/null
+++ b/test_regress/t/t_sys_writemem.gold1.mem
@@ -0,0 +1,14 @@
+02
+03
+04
+05
+06
+07
+10
+00
+00
+00
+14
+15
+00
+00
diff --git a/test_regress/t/t_sys_writemem.gold2.mem b/test_regress/t/t_sys_writemem.gold2.mem
new file mode 100644
index 000000000..a1d3db086
--- /dev/null
+++ b/test_regress/t/t_sys_writemem.gold2.mem
@@ -0,0 +1,8 @@
+10
+11
+12
+13
+14
+15
+16
+17
diff --git a/test_regress/t/t_sys_writemem.gold3.mem b/test_regress/t/t_sys_writemem.gold3.mem
new file mode 100644
index 000000000..86f3c0631
--- /dev/null
+++ b/test_regress/t/t_sys_writemem.gold3.mem
@@ -0,0 +1,16 @@
+00000000000000000000000000000000000000000000
+00000000000000000000000000000000000000000000
+00000000000000000000000000000000000000000000
+00000000000000000000000000000000000000000000
+400437654321276543211765432107654321abcdef10
+00000000000000000000000000000000000000000000
+00000000000000000000000000000000000000000000
+00000000000000000000000000000000000000000000
+00000000000000000000000000000000000000000000
+00000000000000000000000000000000000000000000
+400a37654321276543211765432107654321abcdef11
+400b37654321276543211765432107654321abcdef12
+400c37654321276543211765432107654321abcdef13
+00000000000000000000000000000000000000000000
+00000000000000000000000000000000000000000000
+00000000000000000000000000000000000000000000
diff --git a/test_regress/t/t_sys_writemem.gold4.mem b/test_regress/t/t_sys_writemem.gold4.mem
new file mode 100644
index 000000000..3e397a9d0
--- /dev/null
+++ b/test_regress/t/t_sys_writemem.gold4.mem
@@ -0,0 +1,16 @@
+000000000000000000000000000000000000000000000000
+000000000000000000000000000000000000000000000000
+000000000000000000000000000000000000000000000000
+000000000000000000000000000000000000000000000000
+7755400437654321276543211765432107654321abcdef10
+000000000000000000000000000000000000000000000000
+000000000000000000000000000000000000000000000000
+000000000000000000000000000000000000000000000000
+000000000000000000000000000000000000000000000000
+000000000000000000000000000000000000000000000000
+7755400a37654321276543211765432107654321abcdef11
+7755400b37654321276543211765432107654321abcdef12
+7755400c37654321276543211765432107654321abcdef13
+000000000000000000000000000000000000000000000000
+000000000000000000000000000000000000000000000000
+000000000000000000000000000000000000000000000000
diff --git a/test_regress/t/t_sys_writemem.gold5.mem b/test_regress/t/t_sys_writemem.gold5.mem
new file mode 100644
index 000000000..b25ae23ef
--- /dev/null
+++ b/test_regress/t/t_sys_writemem.gold5.mem
@@ -0,0 +1,14 @@
+02
+03
+04
+05
+06
+07
+10
+00
+00
+00
+14
+15
+00
+00
diff --git a/test_regress/t/t_sys_writemem.pl b/test_regress/t/t_sys_writemem.pl
new file mode 100755
index 000000000..523a44835
--- /dev/null
+++ b/test_regress/t/t_sys_writemem.pl
@@ -0,0 +1,41 @@
+#!/usr/bin/perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. This program is free software; you can
+# redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+
+top_filename("t/t_sys_readmem.v");
+
+# Use random reset to ensure we're fully initializing arrays before
+# $writememh, to avoid miscompares with X's on 4-state simulators.
+$Self->{verilated_randReset} = 2; # 2 == truly random
+
+compile(v_flags2 => [
+            "+define+WRITEMEM_READ_BACK=1",
+            "+define+OUT_TMP1=\\\"$Self->{obj_dir}/tmp1.mem\\\"",
+            "+define+OUT_TMP2=\\\"$Self->{obj_dir}/tmp2.mem\\\"",
+            "+define+OUT_TMP3=\\\"$Self->{obj_dir}/tmp3.mem\\\"",
+            "+define+OUT_TMP4=\\\"$Self->{obj_dir}/tmp4.mem\\\"",
+            "+define+OUT_TMP5=\\\"$Self->{obj_dir}/tmp5.mem\\\"",
+        ]);
+
+execute (
+    check_finished=>1,
+    );
+
+for (my $i = 1; $i <= 5; $i++) {
+    my $gold = "$Self->{t_dir}/t_sys_writemem.gold${i}.mem";
+    my $out = "$Self->{obj_dir}/tmp${i}.mem";
+    print "> diff $gold $out\n";
+    my @diffs = `diff $gold $out`;
+    if (0 < scalar @diffs) {
+        print @diffs;
+        $Self->error("Got unexpected diffs against gold.");
+    }
+}
+
+ok(1);
+1;