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//

// -------------------------------------------------------------

//    Copyright 2004-2009 Synopsys, Inc.

//    Copyright 2010 Mentor Graphics Corporation

//    All Rights Reserved Worldwide

//

//    Licensed under the Apache License, Version 2.0 (the

//    "License"); you may not use this file except in

//    compliance with the License.  You may obtain a copy of

//    the License at

//

//        http://www.apache.org/licenses/LICENSE-2.0

//

//    Unless required by applicable law or agreed to in

//    writing, software distributed under the License is

//    distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR

//    CONDITIONS OF ANY KIND, either express or implied.  See

//    the License for the specific language governing

//    permissions and limitations under the License.

// -------------------------------------------------------------

//

//------------------------------------------------------------------------------

// Title: Virtual Register Field Classes

//

// This section defines the virtual field and callback classes.

//

// A virtual field is set of contiguous bits in one or more memory locations.

// The semantics and layout of virtual fields comes from

// an agreement between the software and the hardware,

// not any physical structures in the DUT.

//

//------------------------------------------------------------------------------

typedef class uvm_vreg_field_cbs;

//------------------------------------------------------------------------------

// Class: uvm_vreg_field

//

// Virtual field abstraction class

//

// A virtual field represents a set of adjacent bits that are

// logically implemented in consecutive memory locations.

//

//------------------------------------------------------------------------------

class uvm_vreg_field extends uvm_object;

   `uvm_object_utils(uvm_vreg_field)

   `uvm_register_cb(uvm_vreg_field, uvm_vreg_field_cbs)

   local uvm_vreg parent;

   local int unsigned lsb;

   local int unsigned size;

   local string fname;

   local int lineno;

   local bit read_in_progress;

   local bit write_in_progress;

   //

   // Group: initialization

   //

   //

   // Function: new

   // Create a new virtual field instance

   //

   // This method should not be used directly.

   // The uvm_vreg_field::type_id::create() method should be used instead.

   //

   extern function new(string name = "uvm_vreg_field");

   //

   // Function: configure

   // Instance-specific configuration

   //

   // Specify the ~parent~ virtual register of this virtual field, its

   // ~size~ in bits, and the position of its least-significant bit

   // within the virtual register relative to the least-significant bit

   // of the virtual register.

   //

   extern function void configure(uvm_vreg parent,

                                  int unsigned size,

                                  int unsigned lsb_pos);

   //

   // Group: Introspection

   //

   //

   // Function: get_name

   // Get the simple name

   //

   // Return the simple object name of this virtual field

   //

   //

   // Function: get_full_name

   // Get the hierarchical name

   //

   // Return the hierarchal name of this virtual field

   // The base of the hierarchical name is the root block.

   //

   extern virtual function string        get_full_name();

   //

   // FUNCTION: get_parent

   // Get the parent virtual register

   //

   extern virtual function uvm_vreg get_parent();

   extern virtual function uvm_vreg get_register();

   //

   // FUNCTION: get_lsb_pos_in_register

   // Return the position of the virtual field

   ///

   // Returns the index of the least significant bit of the virtual field

   // in the virtual register that instantiates it.

   // An offset of 0 indicates a field that is aligned with the

   // least-significant bit of the register.

   //

   extern virtual function int unsigned get_lsb_pos_in_register();

   //

   // FUNCTION: get_n_bits

   // Returns the width, in bits, of the virtual field.

   //

   extern virtual function int unsigned get_n_bits();

   //

   // FUNCTION: get_access

   // Returns the access policy of the virtual field register

   // when written and read via an address map.

   //

   // If the memory implementing the virtual field

   // is mapped in more than one address map,

   // an address ~map~ must be specified.

   // If access restrictions are present when accessing a memory

   // through the specified address map, the access mode returned

   // takes the access restrictions into account.

   // For example, a read-write memory accessed

   // through an address map with read-only restrictions would return "RO".

   //

   extern virtual function string get_access(uvm_reg_map map = null);

   //

   // Group: HDL Access

   //

   //

   // TASK: write

   // Write the specified value in a virtual field

   //

   // Write ~value~ in the DUT memory location(s) that implements

   // the virtual field that corresponds to this

   // abstraction class instance using the specified access

   // ~path~.

   //

   // If the memory implementing the virtual register array

   // containing this virtual field

   // is mapped in more than one address map,

   // an address ~map~ must be

   // specified if a physical access is used (front-door access).

   //

   // The operation is eventually mapped into

   // memory read-modify-write operations at the location

   // where the virtual register

   // specified by ~idx~ in the virtual register array is implemented.

   // If a backdoor is available for the memory implementing the

   // virtual field, it will be used for the memory-read operation.

   //

   extern virtual task write(input  longint unsigned   idx,

                             output uvm_status_e  status,

                             input  uvm_reg_data_t     value,

                             input  uvm_path_e    path = UVM_DEFAULT_PATH,

                             input  uvm_reg_map        map = null,

                             input  uvm_sequence_base  parent = null,

                             input  uvm_object         extension = null,

                             input  string             fname = "",

                             input  int                lineno = 0);

   //

   // TASK: read

   // Read the current value from a virtual field

   //

   // Read from the DUT memory location(s) that implements

   // the virtual field that corresponds to this

   // abstraction class instance using the specified access

   // ~path~, and return the readback ~value~.

   //

   // If the memory implementing the virtual register array

   // containing this virtual field

   // is mapped in more than one address map,

   // an address ~map~ must be

   // specified if a physical access is used (front-door access).

   //

   // The operation is eventually mapped into

   // memory read operations at the location(s)

   // where the virtual register

   // specified by ~idx~ in the virtual register array is implemented.

   //

   extern virtual task read(input  longint unsigned    idx,

                            output uvm_status_e   status,

                            output uvm_reg_data_t      value,

                            input  uvm_path_e     path = UVM_DEFAULT_PATH,

                            input  uvm_reg_map         map = null,

                            input  uvm_sequence_base   parent = null,

                            input  uvm_object          extension = null,

                            input  string              fname = "",

                            input  int                 lineno = 0);

   //

   // TASK: poke

   // Deposit the specified value in a virtual field

   //

   // Deposit ~value~ in the DUT memory location(s) that implements

   // the virtual field that corresponds to this

   // abstraction class instance using the specified access

   // ~path~.

   //

   // The operation is eventually mapped into

   // memory peek-modify-poke operations at the location

   // where the virtual register

   // specified by ~idx~ in the virtual register array is implemented.

   //

   extern virtual task poke(input  longint unsigned    idx,

                            output uvm_status_e   status,

                            input  uvm_reg_data_t      value,

                            input  uvm_sequence_base   parent = null,

                            input  uvm_object          extension = null,

                            input  string              fname = "",

                            input  int                 lineno = 0);

   //

   // TASK: peek

   // Sample the current value from a virtual field

   //

   // Sample from the DUT memory location(s) that implements

   // the virtual field that corresponds to this

   // abstraction class instance using the specified access

   // ~path~, and return the readback ~value~.

   //

   // If the memory implementing the virtual register array

   // containing this virtual field

   // is mapped in more than one address map,

   // an address ~map~ must be

   // specified if a physical access is used (front-door access).

   //

   // The operation is eventually mapped into

   // memory peek operations at the location(s)

   // where the virtual register

   // specified by ~idx~ in the virtual register array is implemented.

   //

   extern virtual task peek(input  longint unsigned    idx,

                            output uvm_status_e   status,

                            output uvm_reg_data_t      value,

                            input  uvm_sequence_base   parent = null,

                            input  uvm_object          extension = null,

                            input  string              fname = "",

                            input  int                 lineno = 0);

   //

   // Group: Callbacks

   //

   //

   // TASK: pre_write

   // Called before virtual field write.

   //

   // If the specified data value, access ~path~ or address ~map~ are modified,

   // the updated data value, access path or address map will be used

   // to perform the virtual register operation.

   //

   // The virtual field callback methods are invoked before the callback methods

   // on the containing virtual register.

   // The registered callback methods are invoked after the invocation

   // of this method.

   // The pre-write virtual register and field callbacks are executed

   // before the corresponding pre-write memory callbacks

   //

   virtual task pre_write(longint unsigned     idx,

                          ref uvm_reg_data_t   wdat,

                          ref uvm_path_e  path,

                          ref uvm_reg_map   map);

   endtask: pre_write

   //

   // TASK: post_write

   // Called after virtual field write

   //

   // If the specified ~status~ is modified,

   // the updated status will be

   // returned by the virtual register operation.

   //

   // The virtual field callback methods are invoked after the callback methods

   // on the containing virtual register.

   // The registered callback methods are invoked before the invocation

   // of this method.

   // The post-write virtual register and field callbacks are executed

   // after the corresponding post-write memory callbacks

   //

   virtual task post_write(longint unsigned       idx,

                           uvm_reg_data_t         wdat,

                           uvm_path_e        path,

                           uvm_reg_map         map,

                           ref uvm_status_e  status);

   endtask: post_write

   //

   // TASK: pre_read

   // Called before virtual field read.

   //

   // If the specified access ~path~ or address ~map~ are modified,

   // the updated access path or address map will be used to perform

   // the virtual register operation.

   //

   // The virtual field callback methods are invoked after the callback methods

   // on the containing virtual register.

   // The registered callback methods are invoked after the invocation

   // of this method.

   // The pre-read virtual register and field callbacks are executed

   // before the corresponding pre-read memory callbacks

   //

   virtual task pre_read(longint unsigned      idx,

                         ref uvm_path_e   path,

                         ref uvm_reg_map    map);

   endtask: pre_read

   //

   // TASK: post_read

   // Called after virtual field read.

   //

   // If the specified readback data ~rdat~ or ~status~ is modified,

   // the updated readback data or status will be

   // returned by the virtual register operation.

   //

   // The virtual field callback methods are invoked after the callback methods

   // on the containing virtual register.

   // The registered callback methods are invoked before the invocation

   // of this method.

   // The post-read virtual register and field callbacks are executed

   // after the corresponding post-read memory callbacks

   //

   virtual task post_read(longint unsigned       idx,

                          ref uvm_reg_data_t     rdat,

                          uvm_path_e        path,

                          uvm_reg_map         map,

                          ref uvm_status_e  status);

   endtask: post_read

   extern virtual function void do_print (uvm_printer printer);

   extern virtual function string convert2string;

   extern virtual function uvm_object clone();

   extern virtual function void do_copy   (uvm_object rhs);

   extern virtual function bit do_compare (uvm_object  rhs,

                                          uvm_comparer comparer);

   extern virtual function void do_pack (uvm_packer packer);

   extern virtual function void do_unpack (uvm_packer packer);

endclass: uvm_vreg_field

//------------------------------------------------------------------------------

// Class: uvm_vreg_field_cbs

//

// Pre/post read/write callback facade class

//

//------------------------------------------------------------------------------

class uvm_vreg_field_cbs extends uvm_callback;

   string fname;

   int    lineno;

   function new(string name = "uvm_vreg_field_cbs");

      super.new(name);

   endfunction

   //

   // Task: pre_write

   // Callback called before a write operation.

   //

   // The registered callback methods are invoked before the invocation

   // of the virtual register pre-write callbacks and

   // after the invocation of the  method.

   //

   // The written value ~wdat~, access ~path~ and address ~map~,

   // if modified, modifies the actual value, access path or address map

   // used in the register operation.

   //

   virtual task pre_write(uvm_vreg_field       field,

                          longint unsigned     idx,

                          ref uvm_reg_data_t   wdat,

                          ref uvm_path_e  path,

                          ref uvm_reg_map   map);

   endtask: pre_write

   //

   // TASK: post_write

   // Called after a write operation

   //

   // The registered callback methods are invoked after the invocation

   // of the virtual register post-write callbacks and

   // before the invocation of the  method.

   //

   // The ~status~ of the operation,

   // if modified, modifies the actual returned status.

   //

   virtual task post_write(uvm_vreg_field        field,

                           longint unsigned      idx,

                           uvm_reg_data_t        wdat,

                           uvm_path_e       path,

                           uvm_reg_map        map,

                           ref uvm_status_e status);

   endtask: post_write

   //

   // TASK: pre_read

   // Called before a virtual field read.

   //

   // The registered callback methods are invoked after the invocation

   // of the virtual register pre-read callbacks and

   // after the invocation of the  method.

   //

   // The access ~path~ and address ~map~,

   // if modified, modifies the actual access path or address map

   // used in the register operation.

   //

   virtual task pre_read(uvm_vreg_field        field,

                         longint unsigned      idx,

                         ref uvm_path_e   path,

                         ref uvm_reg_map    map);

   endtask: pre_read

   //

   // TASK: post_read

   // Called after a virtual field read.

   //

   // The registered callback methods are invoked after the invocation

   // of the virtual register post-read callbacks and

   // before the invocation of the  method.

   //

   // The readback value ~rdat~ and the ~status~ of the operation,

   // if modified, modifies the actual returned readback value and status.

   //

   virtual task post_read(uvm_vreg_field         field,

                          longint unsigned       idx,

                          ref uvm_reg_data_t     rdat,

                          uvm_path_e        path,

                          uvm_reg_map         map,

                          ref uvm_status_e  status);

   endtask: post_read

endclass: uvm_vreg_field_cbs

//

// Type: uvm_vreg_field_cb

// Convenience callback type declaration

//

// Use this declaration to register virtual field callbacks rather than

// the more verbose parameterized class

//

typedef uvm_callbacks#(uvm_vreg_field, uvm_vreg_field_cbs) uvm_vreg_field_cb;

//

// Type: uvm_vreg_field_cb_iter

// Convenience callback iterator type declaration

//

// Use this declaration to iterate over registered virtual field callbacks

// rather than the more verbose parameterized class

//

typedef uvm_callback_iter#(uvm_vreg_field, uvm_vreg_field_cbs) uvm_vreg_field_cb_iter;

function uvm_vreg_field::new(string name="uvm_vreg_field");

   super.new(name);

endfunction: new

function void uvm_vreg_field::configure(uvm_vreg  parent,

                                   int unsigned  size,

                                   int unsigned  lsb_pos);

   this.parent = parent;

   if (size == 0) begin

      `uvm_error("RegModel", $sformatf("Virtual field \"%s\" cannot have 0 bits", this.get_full_name()));

      size = 1;

   end

   if (size > `UVM_REG_DATA_WIDTH) begin

      `uvm_error("RegModel", $sformatf("Virtual field \"%s\" cannot have more than %0d bits",

                                     this.get_full_name(),

                                     `UVM_REG_DATA_WIDTH));

      size = `UVM_REG_DATA_WIDTH;

   end

   this.size   = size;

   this.lsb    = lsb_pos;

   this.parent.add_field(this);

endfunction: configure

function string uvm_vreg_field::get_full_name();

   get_full_name = {this.parent.get_full_name(), ".", this.get_name()};

endfunction: get_full_name

function uvm_vreg uvm_vreg_field::get_register();

   get_register = this.parent;

endfunction: get_register

function uvm_vreg uvm_vreg_field::get_parent();

   get_parent = this.parent;

endfunction: get_parent

function int unsigned uvm_vreg_field::get_lsb_pos_in_register();

   get_lsb_pos_in_register = this.lsb;

endfunction: get_lsb_pos_in_register

function int unsigned uvm_vreg_field::get_n_bits();

   get_n_bits = this.size;

endfunction: get_n_bits

function string uvm_vreg_field::get_access(uvm_reg_map map = null);

   if (this.parent.get_memory() == null) begin

      `uvm_error("RegModel", $sformatf("Cannot call uvm_vreg_field::get_rights() on unimplemented virtual field \"%s\"",

                                     this.get_full_name()));

      return "RW";

   end

   return this.parent.get_access(map);

endfunction: get_access

task uvm_vreg_field::write(input  longint unsigned    idx,

                           output uvm_status_e   status,

                           input  uvm_reg_data_t      value,

                           input  uvm_path_e     path = UVM_DEFAULT_PATH,

                           input  uvm_reg_map      map = null,

                           input  uvm_sequence_base   parent = null,

                           input  uvm_object          extension = null,

                           input  string              fname = "",

                           input  int                 lineno = 0);

   uvm_reg_data_t  tmp;

   uvm_reg_data_t  segval;

   uvm_reg_addr_t  segoff;

   uvm_status_e st;

   int flsb, fmsb, rmwbits;

   int segsiz, segn;

   uvm_mem    mem;

   uvm_path_e rm_path;

   uvm_vreg_field_cb_iter cbs = new(this);

   this.fname = fname;

   this.lineno = lineno;

   write_in_progress = 1'b1;

   mem = this.parent.get_memory();

   if (mem == null) begin

      `uvm_error("RegModel", $sformatf("Cannot call uvm_vreg_field::write() on unimplemented virtual register \"%s\"",

                                     this.get_full_name()));

      status = UVM_NOT_OK;

      return;

   end

   if (path == UVM_DEFAULT_PATH) begin

      uvm_reg_block blk = this.parent.get_block();

      path = blk.get_default_path();

   end

   status = UVM_IS_OK;

   this.parent.XatomicX(1);

   if (value >> this.size) begin

      `uvm_warning("RegModel", $sformatf("Writing value 'h%h that is greater than field \"%s\" size (%0d bits)", value, this.get_full_name(), this.get_n_bits()));

      value &= value & ((1<

   end

   tmp = 0;

   this.pre_write(idx, value, path, map);

   for (uvm_vreg_field_cbs cb = cbs.first(); cb != null;

        cb = cbs.next()) begin

      cb.fname = this.fname;

      cb.lineno = this.lineno;

      cb.pre_write(this, idx, value, path, map);

   end

   segsiz = mem.get_n_bytes() * 8;

   flsb    = this.get_lsb_pos_in_register();

   segoff  = this.parent.get_offset_in_memory(idx) + (flsb / segsiz);

   // Favor backdoor read to frontdoor read for the RMW operation

   rm_path = UVM_DEFAULT_PATH;

   if (mem.get_backdoor() != null) rm_path = UVM_BACKDOOR;

   // Any bits on the LSB side we need to RMW?

   rmwbits = flsb % segsiz;

   // Total number of memory segment in this field

   segn = (rmwbits + this.get_n_bits() - 1) / segsiz + 1;

   if (rmwbits > 0) begin

      uvm_reg_addr_t  segn;

      mem.read(st, segoff, tmp, rm_path, map, parent, , extension, fname, lineno);

      if (st != UVM_IS_OK && st != UVM_HAS_X) begin

         `uvm_error("RegModel",

                    $sformatf("Unable to read LSB bits in %s[%0d] to for RMW cycle on virtual field %s.",

                              mem.get_full_name(), segoff, this.get_full_name()));

         status = UVM_NOT_OK;

         this.parent.XatomicX(0);

         return;

      end

      value = (value << rmwbits) | (tmp & ((1<

   end

   // Any bits on the MSB side we need to RMW?

   fmsb = rmwbits + this.get_n_bits() - 1;

   rmwbits = (fmsb+1) % segsiz;

   if (rmwbits > 0) begin

      if (segn > 0) begin

         mem.read(st, segoff + segn - 1, tmp, rm_path, map, parent,, extension, fname, lineno);

         if (st != UVM_IS_OK && st != UVM_HAS_X) begin

            `uvm_error("RegModel",

                       $sformatf("Unable to read MSB bits in %s[%0d] to for RMW cycle on virtual field %s.",

                                 mem.get_full_name(), segoff+segn-1,

                                 this.get_full_name()));

            status = UVM_NOT_OK;

            this.parent.XatomicX(0);

            return;

         end

      end

      value |= (tmp & ~((1<

   end

   // Now write each of the segments

   tmp = value;

   repeat (segn) begin

      mem.write(st, segoff, tmp, path, map, parent,, extension, fname, lineno);

      if (st != UVM_IS_OK && st != UVM_HAS_X) status = UVM_NOT_OK;

      segoff++;

      tmp = tmp >> segsiz;

   end

   this.post_write(idx, value, path, map, status);

   for (uvm_vreg_field_cbs cb = cbs.first(); cb != null;

        cb = cbs.next()) begin

      cb.fname = this.fname;

      cb.lineno = this.lineno;

      cb.post_write(this, idx, value, path, map, status);

   end

   this.parent.XatomicX(0);

   `uvm_info("RegModel", $sformatf("Wrote virtual field \"%s\"[%0d] via %s with: 'h%h",

                              this.get_full_name(), idx,

                              (path == UVM_FRONTDOOR) ? "frontdoor" : "backdoor",

                              value),UVM_MEDIUM);

   write_in_progress = 1'b0;

   this.fname = "";

   this.lineno = 0;

endtask: write

task uvm_vreg_field::read(input longint unsigned     idx,

                          output uvm_status_e   status,

                          output uvm_reg_data_t      value,

                          input  uvm_path_e     path = UVM_DEFAULT_PATH,

                          input  uvm_reg_map      map = null,

                          input  uvm_sequence_base   parent = null,

                          input  uvm_object          extension = null,

                          input  string              fname = "",

                          input  int                 lineno = 0);

   uvm_reg_data_t  tmp;

   uvm_reg_data_t  segval;

   uvm_reg_addr_t  segoff;

   uvm_status_e st;

   int flsb, lsb;

   int segsiz, segn;

   uvm_mem    mem;

   uvm_vreg_field_cb_iter cbs = new(this);

   this.fname = fname;

   this.lineno = lineno;

   read_in_progress = 1'b1;

   mem = this.parent.get_memory();

   if (mem == null) begin

      `uvm_error("RegModel", $sformatf("Cannot call uvm_vreg_field::read() on unimplemented virtual register \"%s\"",

                                     this.get_full_name()));

      status = UVM_NOT_OK;

      return;

   end

   if (path == UVM_DEFAULT_PATH) begin

      uvm_reg_block blk = this.parent.get_block();

      path = blk.get_default_path();

   end

   status = UVM_IS_OK;

   this.parent.XatomicX(1);

   value = 0;

   this.pre_read(idx, path, map);

   for (uvm_vreg_field_cbs cb = cbs.first(); cb != null;

        cb = cbs.next()) begin

      cb.fname = this.fname;

      cb.lineno = this.lineno;

      cb.pre_read(this, idx, path, map);

   end

   segsiz = mem.get_n_bytes() * 8;

   flsb    = this.get_lsb_pos_in_register();

   segoff  = this.parent.get_offset_in_memory(idx) + (flsb / segsiz);

   lsb = flsb % segsiz;

   // Total number of memory segment in this field

   segn = (lsb + this.get_n_bits() - 1) / segsiz + 1;

   // Read each of the segments, MSB first

   segoff += segn - 1;

   repeat (segn) begin

      value = value << segsiz;

      mem.read(st, segoff, tmp, path, map, parent, , extension, fname, lineno);

      if (st != UVM_IS_OK && st != UVM_HAS_X) status = UVM_NOT_OK;

      segoff--;

      value |= tmp;

   end

   // Any bits on the LSB side we need to get rid of?

   value = value >> lsb;

   // Any bits on the MSB side we need to get rid of?

   value &= (1<

   this.post_read(idx, value, path, map, status);

   for (uvm_vreg_field_cbs cb = cbs.first(); cb != null;

        cb = cbs.next()) begin

      cb.fname = this.fname;

      cb.lineno = this.lineno;

      cb.post_read(this, idx, value, path, map, status);

   end

   this.parent.XatomicX(0);

   `uvm_info("RegModel", $sformatf("Read virtual field \"%s\"[%0d] via %s: 'h%h",

                              this.get_full_name(), idx,

                              (path == UVM_FRONTDOOR) ? "frontdoor" : "backdoor",

                              value),UVM_MEDIUM);

   read_in_progress = 1'b0;

   this.fname = "";

   this.lineno = 0;

endtask: read

task uvm_vreg_field::poke(input  longint unsigned  idx,

                          output uvm_status_e status,

                          input  uvm_reg_data_t    value,

                          input  uvm_sequence_base parent = null,

                          input  uvm_object        extension = null,

                          input  string            fname = "",

                          input  int               lineno = 0);

   uvm_reg_data_t  tmp;

   uvm_reg_data_t  segval;

   uvm_reg_addr_t  segoff;

   uvm_status_e st;

   int flsb, fmsb, rmwbits;

   int segsiz, segn;

   uvm_mem    mem;

   uvm_path_e rm_path;

   this.fname = fname;

   this.lineno = lineno;

   mem = this.parent.get_memory();

   if (mem == null) begin

      `uvm_error("RegModel", $sformatf("Cannot call uvm_vreg_field::poke() on unimplemented virtual register \"%s\"",

                                     this.get_full_name()));

      status = UVM_NOT_OK;

      return;

   end

   status = UVM_IS_OK;

   this.parent.XatomicX(1);

   if (value >> this.size) begin

      `uvm_warning("RegModel", $sformatf("Writing value 'h%h that is greater than field \"%s\" size (%0d bits)", value, this.get_full_name(), this.get_n_bits()));

      value &= value & ((1<

   end

   tmp = 0;

   segsiz = mem.get_n_bytes() * 8;

   flsb    = this.get_lsb_pos_in_register();

   segoff  = this.parent.get_offset_in_memory(idx) + (flsb / segsiz);

   // Any bits on the LSB side we need to RMW?

   rmwbits = flsb % segsiz;

   // Total number of memory segment in this field

   segn = (rmwbits + this.get_n_bits() - 1) / segsiz + 1;

   if (rmwbits > 0) begin

      uvm_reg_addr_t  segn;

      mem.peek(st, segoff, tmp, "", parent, extension, fname, lineno);

      if (st != UVM_IS_OK && st != UVM_HAS_X) begin

         `uvm_error("RegModel",

                    $sformatf("Unable to read LSB bits in %s[%0d] to for RMW cycle on virtual field %s.",

                              mem.get_full_name(), segoff, this.get_full_name()));

         status = UVM_NOT_OK;

         this.parent.XatomicX(0);

         return;

      end

      value = (value << rmwbits) | (tmp & ((1<

   end

   // Any bits on the MSB side we need to RMW?

   fmsb = rmwbits + this.get_n_bits() - 1;

   rmwbits = (fmsb+1) % segsiz;

   if (rmwbits > 0) begin

      if (segn > 0) begin

         mem.peek(st, segoff + segn - 1, tmp, "", parent, extension, fname, lineno);

         if (st != UVM_IS_OK && st != UVM_HAS_X) begin

            `uvm_error("RegModel",

                       $sformatf("Unable to read MSB bits in %s[%0d] to for RMW cycle on virtual field %s.",

                                 mem.get_full_name(), segoff+segn-1,

                                 this.get_full_name()));

            status = UVM_NOT_OK;

            this.parent.XatomicX(0);

            return;

         end

      end

      value |= (tmp & ~((1<

   end

   // Now write each of the segments

   tmp = value;

   repeat (segn) begin

      mem.poke(st, segoff, tmp, "", parent, extension, fname, lineno);

      if (st != UVM_IS_OK && st != UVM_HAS_X) status = UVM_NOT_OK;

      segoff++;

      tmp = tmp >> segsiz;

   end

   this.parent.XatomicX(0);

   `uvm_info("RegModel", $sformatf("Wrote virtual field \"%s\"[%0d] with: 'h%h",

                              this.get_full_name(), idx, value),UVM_MEDIUM);

   this.fname = "";

   this.lineno = 0;

endtask: poke

task uvm_vreg_field::peek(input  longint unsigned  idx,

                          output uvm_status_e status,

                          output uvm_reg_data_t    value,

                          input  uvm_sequence_base parent = null,

                          input  uvm_object        extension = null,

                          input  string            fname = "",

                          input  int               lineno = 0);

   uvm_reg_data_t  tmp;

   uvm_reg_data_t  segval;

   uvm_reg_addr_t  segoff;

   uvm_status_e st;

   int flsb, lsb;

   int segsiz, segn;

   uvm_mem    mem;

   this.fname = fname;

   this.lineno = lineno;

   mem = this.parent.get_memory();

   if (mem == null) begin

      `uvm_error("RegModel", $sformatf("Cannot call uvm_vreg_field::peek() on unimplemented virtual register \"%s\"",

                                     this.get_full_name()));

      status = UVM_NOT_OK;

      return;

   end

   status = UVM_IS_OK;

   this.parent.XatomicX(1);

   value = 0;

   segsiz = mem.get_n_bytes() * 8;

   flsb    = this.get_lsb_pos_in_register();

   segoff  = this.parent.get_offset_in_memory(idx) + (flsb / segsiz);

   lsb = flsb % segsiz;

   // Total number of memory segment in this field

   segn = (lsb + this.get_n_bits() - 1) / segsiz + 1;

   // Read each of the segments, MSB first

   segoff += segn - 1;

   repeat (segn) begin

      value = value << segsiz;

      mem.peek(st, segoff, tmp, "", parent, extension, fname, lineno);