얼마 전 babyworm님의 글에서 harry...the ASIC guy의 주소를 발견하고 RSS Feed를 등록해두었는데 최근에 재미있는 포스팅(EDA is Only "Mostly Dead")이 있어서 소개한다.

지난 달 DVCon에서 "EDA: Dead or Alive?"라는 주제로 Panel Discussion이 있었는데, 생사를 거론할 만큼 EDA업계가 요새 굉장히 어려운 것 같다.

Donny 

Supported SDC Constraints
    all_clocks
    all_inputs
    all_outputs
    create_clock
    create_generated_clock
    current_design
    expr
    get_cells
    get_clocks
    get_lib_cells
    get_lib_pins
    get_libs
    get_ports
    list
    set
    set_case_analysis
    set_clock_gating_check
    set_clock_latency
    set_clock_transition
    set_clock_uncertainty
    set_disable_timing
    set_drive
    set_driving_cell
    set_false_path
    set_hierarchy_separator
    set_input_delay
    set_input_transition
    set_load
    set_logic_one
    set_logic_zero
    set_max_capacitance
    set_max_delay
    set_max_time_borrow
    set_max_transition
    set_min_capacitance
    set_min_delay
    set_muticycle_path
    set_output_delay
    set_propagated_clock

Not-supported SDC Constraints
    current_instance (If you use "*" as the argument, the current_instance command can be used.)
    get_nets
    get_pins
    set_fanout_load
    set_logic_dc
    set_max_area
    set_max_fanout
    set_operating_conditions
    set_resistance
    set_wire_load_min_block_size
    set_wire_load_mode
    set_wire_load_model
    set_wire_load_selection_group
    set_port_fanout_number

Donny 

Astro에서 Timing이 민감한 cell들을 인접하게 place하거나 output buffer를 output port에 최대한 가깝게 place할 때 유용한 기능.
Thanks to Dr. Choi~

Donny's Guideline: 직접 P&R을 할 줄 알면 더 좋지만 그렇지 않더라도 P&R툴의 기능을 알아야 back-end engineer에게 요구를 할 수 있으므로 유용한 기능들은 알아두는 것이 좋다. 또, Astro의 command까진 아니더라도, 합성에 사용한 synopsys의 constraints들이 P&R에 어떤 영향을 주는지를 파악해 두는 것도 유용하다.

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netWeight

The netWeight function sets the net priorities (or weights) for placing cells. During placement, the Milkyway-based tool attempts to place cells connected to high-priority nets closer together.

The primary goal of your Synopsys application, regardless of the specified net weights, is to achieve the minimum total net length for the design. Therefore, the Synopsys application weighs any reduction in the length of a high-priority net against the effect on the overall net length.

Nets with no priority set have the lowest priority (net weight of 1).

You can set net weights while running a Synopsys application by using Constraints > Set Net Weight.

Syntax

netWeight netName netWtHorizontal netWtVertical 

where the arguments are as follows:

netName
         Name of the net to be prioritized.

         Valid values: Name of any net in the design
netWtHorizontal
         Weight to be given to horizontal wires on the net. The higher the value, the greater priority the Synopsys application gives the net.

         Valid values: Any positive integer
netWtVertical
         Weight to be given to vertical wires on the net. The higher the value, the greater priority the Synopsys application gives the net.

         Valid values: Any positive integer

Example

netWeight "CTL2" 10 8
netWeight "CTL3" 4 2
netWeight "CTL4" 6 6

Using these net priority directives, the Synopsys application gives the highest priority to horizontal wires on the CTL2 net and the lowest priority to vertical wires on the CTL3 net (except for nets not specified, which receive the lowest priority). For nets CTL2 and CTL3, horizontal
wires are given higher priority than vertical wires. For net CTL4, horizontal and vertical wires are given equal priority.

출처: Astro 2007.03-SP4 Help

Donny