IDesignSpec NextGen™

The above-implemented alias property will make the following RTL code:

UVM Code:

Alias_cb Alias_Block1_Reg1_Fld;
Alias_cb Alias_aliasBlock_aliasReg1_Fld;
Alias_cb Alias_Block1_Reg2_Fld2;
Alias_cb Alias_aliasBlock_aliasReg2_Fld2;

Alias_Block1_Reg1_Fld = new(“Alias_Block1_Reg1_Fld”, Block1.Reg1.Fld);
uvm_reg_field_cb::add(aliasBlock.aliasReg1.Fld, Alias_Block1_Reg1_Fld);

Alias_aliasBlock_aliasReg1_Fld = new(“Alias_aliasBlock_aliasReg1_Fld”, aliasBlock.aliasReg1.Fld);
uvm_reg_field_cb::add(Block1.Reg1.Fld, Alias_aliasBlock_aliasReg1_Fld);

Alias_Block1_Reg2_Fld2 = new(“Alias_Block1_Reg2_Fld2”, Block1.Reg2.Fld2);
uvm_reg_field_cb::add(aliasBlock.aliasReg2.Fld2, Alias_Block1_Reg2_Fld2);

Alias_aliasBlock_aliasReg2_Fld2 = new(“Alias_aliasBlock_aliasReg2_Fld2”, aliasBlock.aliasReg2.Fld2);
uvm_reg_field_cb::add(Block1.Reg2.Fld2, Alias_aliasBlock_aliasReg2_Fld2);

Usage:

As an example, Alias Register is used in MPU(memory Protection unit).The reason to use this is to allow multiple MPU regions to be accessed and programmed in one instruction, such as store-multiple (STM), to save time and speed up the execution of the programs.

Conclusion:

Alias register is very important in terms of writing specs for industry use and making the process faster resulting in timely execution of the specs. Alias can be made between registers within one block and between registers located in two separate blocks as well, making it even more versatile.

Format property in IDS/ISS

Format property implementation for IDS/ISS

Introduction

Normally only integers are represented in fixed point numbers. This implicitly means that the decimal point is at the right most corner of a number. Also, integers can be signed (2’s complement) or unsigned. However, in Math intensive applications, fixed point numbers can also be used to represent real numbers. In this case the decimal point moves towards left of the number.

A new property is introduced called “format”. Its value will be of the form “fixdt(,,)”. This property constructs fixed-point numeric values from real values. It works in the similar manner as the “fi” function used in MATLAB, to construct fixed-point numeric object.

The integer value is calculated using the following formula –

Real value = (Integer value) x 2^{(-fractional bits)}

In case the calculated Integer value is bigger than the field length, of register field on which the “format” property is applied, then the integer value saturates to the field length.

Eg: “{format=fixdt(1,,5)}”, applied on the register field of length ‘8’ and having value ‘30.5’, with ‘5’ fractional bits, returns value 127. From the above formula the integer value comes out to be ‘976’ but as the field length is only ‘8’ including the sign bit, so, the returned integer value saturates to (27 – 1) i.e. ‘127’.

The value of fractional bits can be negative also. It can also be greater than the length of the field. The integer value is calculated in the same manner described above. Eg:

• “{format=fixdt(0,,-3)}”, applied on the register field of length ‘9’ and having value ‘100.1’, with ‘-3’ returns value ‘13’.
• “{format=fixdt(1,,10)}”, applied on the register field of length ‘7’ and having value ‘0.0048725’, with ‘10’ returns value ‘-5’.

Implementation

Proposed “format” property can be defined on register fields in ISS sequence sheet or on the register fields in the IDS document, if format property is defined on a field both in the IDS document and sequence sheet then, one on the sequence sheet takes precedence. A user can define a real value, in following manner using format property.