MicroTESK

h1. Getting Started with x86

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h2. Prerequisite

MicroTESK should be [[Installation Guide|installed]].

h2. Demo Specifications

Specifications of the x86 (8086) instruction set architecture (ISA) can be found in "$MICROTESK_HOME/arch/demo/x86/model/x86.nml":http://forge.ispras.ru/projects/microtesk/repository/entry/trunk/microtesk/src/main/arch/demo/x86/model/x86.nml.

Instruction are described in [[nML Language Reference|nML]] by means of the following constructs (_move r16/r16_ is taken as an example):

## the signature

<pre><code class="c">op mov_r16r16 (dst: GPR16, src: GPR16)</code></pre>

## the assembly format

<pre><code class="c">syntax = format("mov %s, %s", dst.syntax, src.syntax)</code></pre>

## the binary encoding

<pre><code class="c">image = format("1000101111%s%s", dst.image, src.image)</code></pre>

## the semantics

<pre><code class="c">

  action = {

    dst = src;

    ...

  }

</code></pre>

To compile the ISA model, run the following command:

<pre>sh $MICROTESK_HOME/bin/compile.sh x86.nml</pre>

h2. Demo Templates

Test templates for the x86 ISA can be found in "$MICROTESK_HOME/arch/demo/x86/templates":http://forge.ispras.ru/projects/microtesk/repository/entry/trunk/microtesk/src/main/arch/demo/x86/templates.

The directory contains a number of demo templates including the following ones:

{background:#f6fcff}. | "block.rb":http://forge.ispras.ru/projects/microtesk/repository/entry/trunk/microtesk/src/main/arch/demo/x86/templates/block.rb | demonstrates how to use block constructs |

                      | "block_random.rb":http://forge.ispras.ru/projects/microtesk/repository/entry/trunk/microtesk/src/main/arch/demo/x86/templates/block_random.rb | demonstrates how to create randomized instruction sequences using block constructs |

{background:#f6fcff}. | "euclid.rb":http://forge.ispras.ru/projects/microtesk/repository/entry/trunk/microtesk/src/main/arch/demo/x86/templates/euclid.rb | demonstrates test program simulation to predict the resulting microprocessor state |

                      | "random.rb":http://forge.ispras.ru/projects/microtesk/repository/entry/trunk/microtesk/src/main/arch/demo/x86/templates/random.rb | demonstrates how to randomize tests by using biases and distributions |

{background:#f6fcff}. | "random_immediate.rb":http://forge.ispras.ru/projects/microtesk/repository/entry/trunk/microtesk/src/main/arch/demo/x86/templates/random_immediate.rb | demonstrates how to randomize immediate values |

                      | "random_registers.rb":http://forge.ispras.ru/projects/microtesk/repository/entry/trunk/microtesk/src/main/arch/demo/x86/templates/random_registers.rb | demonstrates how to randomize registers (dependencies) |

Test templates are written in "Ruby":http://www.ruby-lang.org extended with specific [[Template_Description_Language|constructs]].

Let''s review one of the templates ("block.rb":http://forge.ispras.ru/projects/microtesk/repository/entry/trunk/microtesk/src/main/arch/demo/x86/templates/block.rb) in detail.

# includes the file where the base class is defined, containing definition of the x86 ISA registers, their preparators, etc.

<pre><code class="ruby">require_relative ''x86_base''</code></pre>

# declares current template class declaration as a heir of X86BaseTemplate

<pre><code class="ruby">class BlockTemplate < X86BaseTemplate</code></pre>

# defines a "run" method (also, "initialize", "pre", and "post" methods are declared in the base class, and always inherited)

<pre><code class="ruby"> def run</code></pre>

# produces a single test case that consists of three instructions

<pre><code class="ruby">

  sequence {

    mov_r16r16 ax, bx

    sub_r16r16 cx, dx

    add_r16r16 gpr16(_), gpr16(_)

  }.run

</code></pre>

# atomic sequence; works as sequence in this context

<pre><code class="ruby">

  atomic {

    mov_r16r16 ax, bx

    add_r16r16 cx, dx

    sub_r16r16 gpr16(_), gpr16(_)

  }.run

</code></pre>

# produces three test cases each consisting of one instruction

<pre><code class="ruby">

  iterate {

    mov_r16r16 ax, bx

    sub_r16r16 cx, dx

    add_r16r16 gpr16(_), gpr16(_)

  }.run

</code></pre>

# produces four test cases consisting of two instructions (Cartesian product composed in a random order)

<pre><code class="ruby">

  block(:combinator => ''product'', :compositor => ''random'') {

    iterate {

      sub_r16r16 cx, dx

      add_r16r16 ax, bx

    }

    iterate {

      mov_r16r16 ax, bx

      sub_r16r16 gpr16(_), gpr16(_)

    }

  }.run

</code></pre>

# merges two sequences in random fashion; atomic sequences are unmodifiable

<pre><code class="ruby">

  block(:combinator => ''diagonal'', :compositor => ''random'', :obfuscator => ''random'') {

    sequence {

      sub_r16r16 bx, ax

      or_r16r16 cx, dx

    }

    atomic {

      prologue { comment ''Atomic starts'' }

      epilogue { comment ''Atomic ends'' }

      and_r16r16 gpr16(_), gpr16(_)

    }

  }.run

</code></pre>

To generate test program(s) from a test template (in our case, from @block.rb@), run the following command:

<pre>sh $MICROTESK_HOME/bin/generate.sh x86 block.rb --code-file-prefix block --code-file-extension s -v</pre>

When generation is finished, the resulting assembly code can be found in @$MICROTESK_HOME@.

To compile "the output file":http://forge.ispras.ru/attachments/download/5127/block_0000.s, run the following commands:

<pre>

nasm -f elf block_0000.s

ld -m i386pe -s -o block_0000 block_0000.o

</pre>

To execute resulted test cases is possible by means of the "online simulator":https://www.tutorialspoint.com/compile_assembly_online.php

!Example_block.png!