Evolution and History of Programming Languages Software/Hardware/System

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Evolution and History of Programming
LanguagesSoftware/Hardware/System
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Software Programming Language
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History Timeline
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Popularity
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The Evolution of Programming Languages

• To build programs, people use languages that are
  similar to human language. The results are
  translated into machine code, which computers
  understand.
• Programming languages fall into three broad
  categories

• Machine languages
• Assembly languages
• Higher-level languages

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The Evolution of Programming Languages - Machine
Languages

• Machine languages (first-generation languages)
  are the most basic type of computer languages,
  consisting of strings of numbers the computer's
  hardware can use.
• Different types of hardware use different machine
  code. For example, IBM computers use different
  machine language than Apple computers.

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The Evolution of Programming Languages - Assembly
Languages

• Assembly languages (second-generation languages)
  are only somewhat easier to work with than
  machine languages.
• To create programs in assembly language,
  developers use cryptic English-like phrases to
  represent strings of numbers.
• The code is then translated into object code,
  using a translator called an assembler.

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The Evolution of Programming Languages -
Higher-Level Languages

• Higher-level languages are more powerful than
  assembly language and allow the programmer to
  work in a more English-like environment.
• Higher-level programming languages are divided
  into three "generations," each more powerful than
  the last

• Third-generation languages
• Fourth-generation languages
• Fifth-generation languages

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Higher-Level Languages - Third-Generation
Languages

• Third-generation languages (3GLs) are the first
  to use true English-like phrasing, making them
  easier to use than previous languages.
• 3GLs are portable, meaning the object code
  created for one type of system can be translated
  for use on a different type of system.
• The following languages are 3GLs

FORTRAN C COBOL C BASIC Java Pascal Acti
veX
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A Typical C Program Development Environment

• 1. Edit
• 2. Preprocess
• 3. Compile
• 4. Link
• 5. Load
• 6. Execute

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Higher-Level Languages - Fourth-Generation
Languages

• Fourth-generation languages (4GLs) are even
  easier to use than 3GLs.
• 4GLs may use a text-based environment (like a
  3GL) or may allow the programmer to work in a
  visual environment, using graphical tools.
• The following languages are 4GLs

Visual Basic (VB) VisualAge Authoring
environments
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Higher-Level Languages - Fifth-Generation
Languages

• Fifth-generation languages (5GLs) are an issue of
  debate in the programming community some
  programmers cannot agree that they even exist.
• These high-level languages would use artificial
  intelligence to create software, making 5GLs
  extremely difficult to develop.
• Solve problems using constraints rather than
  algorithms, used in Artificial Intelligence

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Summary
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Hardware Description Language

• HDL

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HDL

• What and why HDL??

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Hardware Description Language

• Basic idea is a programming language to describe
  hardware
• Initial purpose was to allow abstract design and
  simulation
• Design could be verified then implemented in
  hardware
• Now Synthesis tools allow direct implementation
  from HDL code.
• Large improvement in designer productivity

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HDL

• HDL allows write-run-debug cycle for hardware
  development.
• Similar to programming software
• Much, much faster than design-implement-debug
• Combined with modern Field Programmable Gate
  Array chips large complex circuits (gt100000s of
  gates) can be implemented.

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HDLs

• There are many different HDLs
• Verilog HDL
• ABEL
• VHDL
• VHDL is the most common
• Large standard developed by US DoD
• VHDL VHSIC HDL
• VHSIC Very High Speed Integrated Circuit
• Verilog HDL is second most common
• Easier to use in many ways better for teaching
• C - like syntax

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Verilog HDL

• Verilog constructs are use defined keywords
• Examples and, or, wire, input output
• One important construct is the module
• Modules have inputs and outputs
• Modules can be built up of Verilog primatives or
  of user defined submodules.

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Example Simple Circuit HDL
module smpl_circuit(A,B,C,x,y) input A,B,C
output x,y wire e and g1(e,A,B) not
g2(y, C) or g3(x,e,y) endmodule
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HDL Summary

• Hardware Description Languages allow fast design
  and verification of digital circuits.
• Accurate simulation and testing requires delays
  and inputs to be specified.
• There are three different levels of abstraction
  for modelling circuits.

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System Design Language

• Hardware and Software
• Co-design

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What is Codesign?
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Why Codesign (1) ?
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Why Codesign (2) ?
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Traditional Design Flow
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HW/SW Codesign Flow

• Concurrent design between hardware and software
  using
• Co-simulation
• Co-synthesis

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Codesign Language

• Hardware Description Language (HDL)

• Software Description Language (SDL)
• People know C, so how about languages built on
  C/C?
• SystemC
• SpecC
• Handel-C

Has no tool support. Only useful for influencing
other languages.
Lacks CAD tool support
Proprietary Not universally available
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SystemC History
VSIA SLD Data Types Spec (draft)
Synopsys ATG
Synopsys Fridge
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SystemC Highlights

• Features as a codesign language

• Modules
• Processes
• Ports
• Signals
• Rich set of port and signal types
• Rich set of data types

• Clocks
• Cycle-based simulation
• Multiple abstraction levels
• Communication protocols
• Debugging support
• Waveform tracing

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Current System Design Methodology
C/C System Level Model

• Problems
• Errors in manual conversion from C to HDL
• Disconnect between system model and HDL model
• Multiple system tests

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SummaryQuestions

• Software/Hardware/System
• Design Languages