UVM Backdoor write not happening as expected

UVM
1

Whike trying to do backdoor write, I am seeing that code executes fine without any errors, and the earlier (some non-zero default value) on the register gets over-ridden at the time of backdoor write in the waveform too. However, the backdoor has written “0” on the register instead of the expected value ('h89)

Code:-
write_reg(alu_reg_block_inst.alu_reg1_inst, status, 32’h89, UVM_BACKDOOR);

Register declaration in RTL:-
reg [31:0] alu_reg1

Log File Snippet:-
UVM_INFO /p/com/eda/synopsys/vcsmx/L-2016.06-SP2/etc/uvm/reg/uvm_reg.svh(2831) @ 2945000: reporter [RegMem] backdoor_read from %s tb_top.alu_inst.alu_reg1
UVM_INFO /p/com/eda/synopsys/vcsmx/L-2016.06-SP2/etc/uvm/reg/uvm_reg.svh(2863) @ 2945000: reporter [RegMem] returned backdoor value 0x0
UVM_INFO /p/com/eda/synopsys/vcsmx/L-2016.06-SP2/etc/uvm/reg/uvm_reg.svh(2794) @ 2945000: reporter [RegMem] backdoor_write to tb_top.alu_inst.alu_reg1

What could be the probable reason that backdoor access is happening at the specified timestamp, but over-ride is happening with “0” value?

Thanks,
Melvin

2

In reply to SV_UVM_Baby:

Well, issue was because the following value (corresponding to offset) was being passed in double quotes:-

alu_reg_block_inst.alu_reg1_inst.add_hdl_path_slice(.name(“alu_reg1”), .offset(“0”), .size(32));

Removed the double quotes, and backdoor accesses are happening with right values

alu_reg_block_inst.alu_reg1_inst.add_hdl_path_slice(.name(“alu_reg1”), .offset(0), .size(32));

Marking this as Solved.