ivl & vvp: Enabled 'string' as the return type in VPI functions.

driver/iverilog.man.in

@@ -384,6 +384,11 @@ The function returns an integer.
 The function returns a vector with the given width, and is signed or
 unsigned according to the flag.
 
+.TP 8
+.B vpiSysFuncString
+The function returns a string. This is an Icarus-specific extension, not
+available in the VPI standard.
+
 .SH "COMMAND FILES"
 The command file allows the user to place source file names and
 certain command line switches into a text file instead of on a long

sv_vpi_user.h

@@ -72,6 +72,10 @@ EXTERN_C_START
 /********* Many-to-One ***********/
 #define vpiMember           742
 
+/* Icarus-specific function type to use string as the return type */
+#define vpiStringFunc       10
+#define vpiSysFuncString    vpiSysFuncString
+
 EXTERN_C_END
 
 #endif /* SV_VPI_USER_H */

sys_funcs.cc

@@ -204,6 +204,17 @@ int load_sys_func_table(const char*path)
 		  continue;
 	    }
 
+	    if (strcmp(stype,"vpiSysFuncString") == 0) {
+		  cell = new struct sfunc_return_type_cell;
+		  cell->name = lex_strings.add(name);
+		  cell->type = IVL_VT_STRING;
+		  cell->wid  = 0;   // string is a dynamic length type
+		  cell->signed_flag = false;
+		  cell->next = sfunc_stack;
+		  sfunc_stack = cell;
+		  continue;
+	    }
+
 	    fprintf(stderr, "%s:%s: Unknown type: %s\n",
 		    path, name, stype);
       }

tgt-vvp/draw_vpi.c

@@ -513,3 +513,14 @@ void draw_vpi_rfunc_call(ivl_expr_t fnet)
 
       draw_vpi_taskfunc_args(call_string, 0, fnet);
 }
+
+void draw_vpi_sfunc_call(ivl_expr_t fnet)
+{
+      char call_string[1024];
+
+      sprintf(call_string, "    %%vpi_func/s %u %u \"%s\"",
+              ivl_file_table_index(ivl_expr_file(fnet)),
+	      ivl_expr_lineno(fnet), ivl_expr_name(fnet));
+
+      draw_vpi_taskfunc_args(call_string, 0, fnet);
+}

tgt-vvp/eval_string.c

@@ -163,6 +163,12 @@ static void string_ex_pop(ivl_expr_t expr)
       fprintf(vvp_out, "    %%qpop/%s/str v%p_0;\n", fb, ivl_expr_signal(arg));
 }
 
+static void draw_sfunc_string(ivl_expr_t expr)
+{
+    assert(ivl_expr_value(expr) == IVL_VT_STRING);
+    draw_vpi_sfunc_call(expr);
+}
+
 void draw_eval_string(ivl_expr_t expr)
 {
 
@@ -195,7 +201,7 @@ void draw_eval_string(ivl_expr_t expr)
 	    else if (strcmp(ivl_expr_name(expr), "$ivl_darray_method$pop_front")==0)
 		  string_ex_pop(expr);
 	    else
-		  fallback_eval(expr);
+		  draw_sfunc_string(expr);
 	    break;
 
 	  case IVL_EX_UFUNC:

tgt-vvp/vvp_priv.h

@@ -133,6 +133,7 @@ extern void draw_vpi_task_call(ivl_statement_t net);
 
 extern void draw_vpi_func_call(ivl_expr_t expr);
 extern void draw_vpi_rfunc_call(ivl_expr_t expr);
+extern void draw_vpi_sfunc_call(ivl_expr_t expr);
 
 extern void draw_class_in_scope(ivl_type_t classtype);
 

vvp/README.txt

@@ -841,6 +841,7 @@ instructions. The formats are:
    %vpi_call/i <file-index> <lineno> <name>, <args>... ;
    %vpi_func <file-index> <lineno> <name>, <args>... ;
    %vpi_func/r <file-index> <lineno> <name>, <args>... ;
+   %vpi_func/s <file-index> <lineno> <name>, <args>... ;
 
 The <file-index> is an index into the string table. The indexed string
 is the source code file name where this call appears. The <lineno> is

vvp/lexor.lex

@@ -234,6 +234,7 @@ static char* strdupnew(char const *str)
 "%vpi_call/i" { return K_vpi_call_i; }
 "%vpi_func"   { return K_vpi_func; }
 "%vpi_func/r" { return K_vpi_func_r; }
+"%vpi_func/s" { return K_vpi_func_s; }
 "%file_line"  { return K_file_line; }
 
   /* Handle the specialized variable access functions. */

vvp/opcodes.txt

@@ -1213,6 +1213,7 @@ stack when the call returns.
 
 * %vpi_func <file> <line> <name> [, ...] {<vec4> <real> <str>}
 * %vpi_func/r <file> <line> <name> [, ...] {<vec4> <real> <str>}
+* %vpi_func/s <file> <line> <name> [, ...] {<vec4> <real> <str>}
 
 This instruction is similar to %vpi_call, except that it is for
 calling system functions. The difference here is the return value from

vvp/parse.y

@@ -100,7 +100,7 @@ static struct __vpiModPath*modpath_dst = 0;
 %token K_VAR_QUEUE
 %token K_VAR_S K_VAR_STR K_VAR_I K_VAR_R K_VAR_2S K_VAR_2U
 %token K_vpi_call K_vpi_call_w K_vpi_call_i
-%token K_vpi_func K_vpi_func_r
+%token K_vpi_func K_vpi_func_r K_vpi_func_s
 %token K_ivl_version K_ivl_delay_selection
 %token K_vpi_module K_vpi_time_precision K_file_names K_file_line
 %token K_PORT_INPUT K_PORT_OUTPUT K_PORT_INOUT K_PORT_MIXED K_PORT_NODIR
@@ -663,6 +663,10 @@ statement
       { compile_vpi_func_call($1, $5, -vpiRealVal, 0, $3, $4,
 			      $6.argc, $6.argv, $8, $9, $10); }
 
+  | label_opt K_vpi_func_s T_NUMBER T_NUMBER T_STRING
+    argument_opt '{' T_NUMBER T_NUMBER T_NUMBER '}' ';'
+      { compile_vpi_func_call($1, $5, -vpiStringVal, 0, $3, $4,
+			      $6.argc, $6.argv, $8, $9, $10); }
 
   /* Scope statements come in two forms. There are the scope
      declaration and the scope recall. The declarations create the

vvp/vpi_tasks.cc

@@ -211,6 +211,51 @@ vpiHandle sysfunc_real::vpi_put_value(p_vpi_value vp, int)
       return 0;
 }
 
+struct sysfunc_string : public __vpiSysTaskCall {
+      inline sysfunc_string() { }
+      int get_type_code(void) const { return vpiSysFuncCall; }
+      int vpi_get(int code);
+      char* vpi_get_str(int code)   { return systask_get_str(code, this); }
+      vpiHandle vpi_put_value(p_vpi_value val, int flags);
+      vpiHandle vpi_handle(int code) { return systask_handle(code, this); }
+      vpiHandle vpi_iterate(int code) { return systask_iter(code, this); }
+
+      std::string return_value_;
+};
+
+int sysfunc_string::vpi_get(int code)
+{
+      switch (code) {
+	  case vpiSize:
+	    return return_value_.size();
+
+	  case vpiLineNo:
+	    return lineno;
+
+	  case vpiUserDefn:
+	    return defn->is_user_defn;
+
+	  default:
+	    return vpiUndefined;
+      }
+}
+
+vpiHandle sysfunc_string::vpi_put_value(p_vpi_value vp, int)
+{
+      put_value = true;
+
+      switch (vp->format) {
+	  case vpiStringVal:
+	    return_value_ = std::string(vp->value.str);
+	    break;
+	  default:
+	    fprintf(stderr, "Unsupported format %d.\n", (int)vp->format);
+	    assert(0);
+      }
+
+      return 0;
+}
+
 class sysfunc_vec4 : public __vpiSysTaskCall {
     public:
       explicit inline sysfunc_vec4(unsigned wid): return_value_(wid, BIT4_X) { }
@@ -845,6 +890,9 @@ vpiHandle vpip_build_vpi_call(const char*name, int val_code, unsigned return_wid
 	    } else if (val_code == -vpiVectorVal) {
 		  obj = new sysfunc_vec4(return_width);
 
+	    } else if (val_code == -vpiStringVal) {
+		  obj = new sysfunc_string;
+
            } else if (val_code == 0 && fnet == 0) {
 		  obj = new sysfunc_no;
 
@@ -957,11 +1005,14 @@ void vpip_execute_vpi_call(vthread_t thr, vpiHandle ref)
       if (vpip_cur_task->string_stack > 0)
 	    vthread_pop_str(thr, vpip_cur_task->string_stack);
 
-	/* If the function has a real value, then push the value
-	   to the thread stack. */
+	/* If the function returns a value, then push the value
+	   to the appropriate thread stack. */
       if (sysfunc_real*func_real = dynamic_cast<sysfunc_real*>(ref)) {
 	    vthread_push_real(thr, func_real->return_value_);
       }
+      if (sysfunc_string*func_string = dynamic_cast<sysfunc_string*>(ref)) {
+	    vthread_push_str(thr, func_string->return_value_);
+      }
       if (sysfunc_vec4*func_vec4 = dynamic_cast<sysfunc_vec4*>(ref)) {
 	    vthread_push_vec4(thr, func_vec4->return_value());
       }

vvp/vthread.cc

@@ -328,6 +328,11 @@ void vthread_push_real(struct vthread_s*thr, double val)
       thr->push_real(val);
 }
 
+void vthread_push_str(struct vthread_s*thr, const string&val)
+{
+      thr->push_str(val);
+}
+
 void vthread_pop_vec4(struct vthread_s*thr, unsigned depth)
 {
       thr->pop_vec4(depth);

vvp/vthread.h

@@ -113,6 +113,7 @@ extern vvp_context_item_t vthread_get_rd_context_item(unsigned context_idx);
  * Access value stacks from thread space.
  */
 extern void vthread_push_vec4(struct vthread_s*thr, const vvp_vector4_t&val);
+extern void vthread_push_str(struct vthread_s*thr, const std::string&val);
 extern void vthread_push_real(struct vthread_s*thr, double val);
 
 extern void vthread_pop_vec4(struct vthread_s*thr, unsigned count);