UVM register model example from uvm-1.1b

[mwhite_cp]

I ran an register model example from UVM 1.1 package and have a question about this. This example is at uvm-1.1b/examples/simple/registers/models/coverage. I ran the Makefile.ius after adding coverage option for coverage analysis. Based on the coverage analysis result, coverage results for cg_bits are all 50%. For each coverpoint, there are 4 auto bins. The auto[0] and auto[3] get hit, but auto[1] and auto[2] don't get hit. Is it possible to achieve 100% coverage result with this code below? This is extracted from regmodel.sv under the directory.

Thanks!

class reg_R extends uvm_reg;

rand uvm_reg_field F1;

rand uvm_reg_field F2;

local uvm_reg_data_t m_current;

local uvm_reg_data_t m_data;

local uvm_reg_data_t m_be;

local bit m_is_read;

covergroup cg_bits;

wF1_0: coverpoint {m_current[0],m_data[0]} iff (!m_is_read && m_be[0]);

wF1_1: coverpoint {m_current[1],m_data[1]} iff (!m_is_read && m_be[0]);

wF1_2: coverpoint {m_current[2],m_data[2]} iff (!m_is_read && m_be[0]);

wF1_3: coverpoint {m_current[3],m_data[3]} iff (!m_is_read && m_be[0]);

wF2_0: coverpoint {m_current[4],m_data[4]} iff (!m_is_read && m_be[0]);

wF2_1: coverpoint {m_current[5],m_data[5]} iff (!m_is_read && m_be[0]);

wF2_2: coverpoint {m_current[6],m_data[6]} iff (!m_is_read && m_be[0]);

wF2_3: coverpoint {m_current[7],m_data[7]} iff (!m_is_read && m_be[0]);

endgroup

covergroup cg_vals;

F1: coverpoint F1.value[3:0];

F2: coverpoint F2.value[3:0];

F1F2: cross F1, F2;

endgroup

function new(string name = "reg_R");

super.new(name, 8, build_coverage(UVM_CVR_REG_BITS +

UVM_CVR_FIELD_VALS));

if (has_coverage(UVM_CVR_REG_BITS))

cg_bits = new();

if (has_coverage(UVM_CVR_FIELD_VALS))

cg_vals = new();

endfunction: new

virtual function void build();

F1 = uvm_reg_field::type_id::create("F1",,get_full_name());

F1.configure(this, 4, 0, "RW", 0, 8'h0, 1, 1, 1);

F2 = uvm_reg_field::type_id::create("F2",,get_full_name());

F2.configure(this, 4, 4, "RO", 0, 8'h0, 1, 1, 1);

endfunction: build

`uvm_object_utils(reg_R)

virtual function void sample(uvm_reg_data_t data,

uvm_reg_data_t byte_en,

bit is_read,

uvm_reg_map map);

if (get_coverage(UVM_CVR_REG_BITS)) begin

m_current = get();

m_data = data;

m_be = byte_en;

m_is_read = is_read;

cg_bits.sample();

end

endfunction

virtual function void sample_values();

super.sample_values();

if (get_coverage(UVM_CVR_FIELD_VALS))

cg_vals.sample();

endfunction

endclass : reg_R