1. OOP for Hardware Verification
̶ Demystified!
Mike Mintz
Co-author, Hardware Verification with C++
and Hardware Verification with SystemVerilog
mike@trusster.com
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2. Overview
• Common Currency
• Data Abstraction
• Virtual Functions
• Base Classes
• Q&A
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3. Common Currency
Sub sole nihil novi est.*
*There is nothing new under the sun.
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4. Data Abstraction
• Procedural code has separate data
structures and functions.
• OOP moves the functions into the
data structure,
• Every possible function for that
structure is now in one place.
• This works well for a driver.
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5. Data Abstraction – Code Details
Procedural Data Abstraction
struct usb_driver {
struct usb_driver {wire d_plus, d_minus;}
wire d_plus, d_minus;
void usb_init (usb_driver * d);
void init ();
void usb_send_packet (usb_driver * d, void send_packet (int type, int* data,
int type, int* data, int length); int length);
void usb_enumerate (usb_driver * d); void enumerate ();
};
begin begin
usb_driver driver; usb_driver driver;
driver. init ();
usb_init (&driver);
driver.enumerate ();
usb_enumerate (&driver); driver.send (0, {0,12}, 2);
usb_send (&driver, 0, {0,12}, 2); end
end
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6. Virtual Function
• Is a run-time function call.
• Is the “I don’t know” function.
• Great for separating concerns
(and increasing portability).
• This works well for a monitor.
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7. Virtual Functions
Monitor class Derived for printing
struct usb_printer: public usb_monitor {
struct usb_monitor { virtual void packet_completed (int length, int* data) {
wire d_plus, d_minus; for (int i(0); i < length; ++i) {
void start_monitor_thread (); printf (“Packet [%d]:0x%xn”, i, data[i]);
}
virtual void packet_completed
}
(int length, int* data) =0;
};
};
Derived for checker Derived for channel
struct usb_checker : public usb_monitor { struct usb_monitor_agent : public usb_monitor {
virtual void packet_completed (int virtual void packet_completed (int length,
length, int* data) { int* data) {
checker_->check (length, data); channel_->put (data_packet (length, data));
} }
checker* checker_; usb_channel* channel_;
}; };
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8. Base Class
• Is a class with one or more virtual
methods.
• Is the “follow my lead” class.
• Sets up a framework or interface.
• This works well for a test irritator.
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9. Base Classes – Code Details
Irritator class Derived for USB
struct irritator { struct usb_irritator : public irritator {
virtual void out_of_reset () =0; virtual void out_of_reset ();
virtual void start () =0; virtual void start ();
virtual void stop () =0; virtual void stop ();
virtual void wait_for_completion () =0; virtual void wait_for_completion ();
}; };
Derived for PCIE Derived for Ethernet
struct pcie_irritator: public irritator { struct ethernet_irritator: public irritator {
virtual void out_of_reset (); virtual void out_of_reset ();
virtual void start (); virtual void start ();
virtual void stop (); virtual void stop ();
virtual void wait_for_completion (); virtual void wait_for_completion ();
}; };
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10. Using OOP – Truss Top-Level
Components
class verification_component {
public:
verification_component (const std::string&);
virtual void randomize () = 0;
virtual void time_zero_setup () = 0;
virtual void out_of_reset (reset r) = 0;
virtual void start () = 0;
virtual void wait_for_completion () = 0;
virtual void report (const std::string) = 0;
};
Source: Hardware Verification with C++, page 95, page 100
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11. The “Dance”
Source: Hardware Verification with C++, page 97 Source: Hardware Verification with C++, page 117
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12. The “Dance” ̶ painfully detailed
Source: Hardware Verification with C++, page 120 Source: Hardware Verification with C++, page 121
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13. Summary
• OOP is a little bit of syntax with a
large amount of attitude.
• Learning OOP is gradual process,
with making mistakes an integral part.
• OOP is not really that “different” – just
different packaging
• See www.trusster.com for forums,
articles, code, and more.
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14. Q & A*
*shameless plug www.trusster.com 14