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jb302@26: \index Index
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jb302@26: 
jb302@26: \begin_body
jb302@26: 
jb302@26: \begin_layout Title
jb302@26: EDE: ELB816 Development Environment
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Author
jb302@26: James Bowden (110104485)
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Abstract
jb302@26: The ELB816 Development Environment consists of an assembler, emulator and
jb302@26:  debugger for the ELB816 microprocessor system.
jb302@27:  This report details the design and usage of each of its elements.
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: \begin_inset Newpage newpage
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@27: \begin_inset CommandInset toc
jb302@27: LatexCommand tableofcontents
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: \begin_inset Newpage newpage
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Part
jb302@27: Introduction and Specification
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: \begin_inset ERT
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jb302@26: \begin_layout Plain Layout
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jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Section
jb302@27: Motivations
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: The ELB816 architecture is designed to be a 
jb302@27: \begin_inset Quotes eld
jb302@27: \end_inset
jb302@27: 
jb302@27: simple to understand 8-bit microprocessor system to help learn about microproces
jb302@27: sor electronics.
jb302@27: \begin_inset Quotes erd
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: \begin_inset ERT
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jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: The combination of an ELB816 emulator, debugger and assembler could be used
jb302@27:  as a set of tools for learning or teaching microprocessor programming without
jb302@27:  the intricacies of real-world commercial microprocessors getting in the
jb302@27:  way of a fundamental understanding of the subject.
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: \begin_inset ERT
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: 
jb302@27: \backslash
jb302@27: bigskip
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: A PC based emulator would allow students to quickly develop and debug programs
jb302@27:  written in a simple assembly language on any modern desktop or laptop and
jb302@27:  an MCS-51 port running on an 8052 would allow students to test programs
jb302@27:  in an actual circuit.
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Section
jb302@27: Project Aims
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Itemize
jb302@27: Develop an assembler for the ELB816 assembly language.
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Itemize
jb302@27: Develop an emulated programmable microprocessor system based on the ELB816
jb302@27:  architecture.
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Itemize
jb302@27: Develop a debugger that allows interactive debugging of programs running
jb302@27:  on the emulator.
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Section
jb302@27: Methodology
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Subsection
jb302@26: Assembler
jb302@26: \end_layout
jb302@26: 
jb302@27: \begin_layout Description
jb302@27: Language: Python
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Description
jb302@27: Priority: First
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: The assembler will be developed before anything else so that it can subsequently
jb302@27:  be used to assemble test programs during development of the emulator.
jb302@27:  
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: \begin_inset Newpage newpage
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@27: \begin_layout Subsection
jb302@26: Emulator
jb302@26: \end_layout
jb302@26: 
jb302@27: \begin_layout Description
jb302@27: Language: C
jb302@26: \end_layout
jb302@26: 
jb302@27: \begin_layout Description
jb302@27: Priority: Second
jb302@27: \end_layout
jb302@27: 
jb302@26: \begin_layout Standard
jb302@27: The emulator will use only standard libraries in order to ensure it is portable
jb302@27:  between compilers and platforms.
jb302@27:  Specifically GCC for x86 and Keil C51 for Intel MCS-51.
jb302@27:  The emulator will first be developed on Linux to facilitated rapid development.
jb302@27:  It will be ported to MCS-51 once it is complete
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Subsection
jb302@26: Debugger
jb302@26: \end_layout
jb302@26: 
jb302@27: \begin_layout Description
jb302@27: Language: C/Python
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Description
jb302@27: Priority: Second
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: The debug interface will be developed along side the emulator.
jb302@27:  It will consist of a simple text based interface built into the emulator
jb302@27:  that will read commands using C's 
jb302@27: \begin_inset listings
jb302@27: lstparams "basicstyle={\ttfamily}"
jb302@27: inline true
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: stdio.h
jb302@27: \end_layout
jb302@27: 
jb302@26: \end_inset
jb302@26: 
jb302@27:  library.
jb302@27:  This means that on Linux the commands will be issued using 
jb302@27: \begin_inset listings
jb302@27: lstparams "basicstyle={\ttfamily}"
jb302@27: inline true
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: STDIN
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27:  and on the MCS-51 version they will be issued over a serial interface.
jb302@27:  Python will be used to provide a cleaner interface for common debug procedures
jb302@27:  such as writing programs to memory and setting break-points.
jb302@27:  
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: \begin_inset ERT
jb302@27: status open
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jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: 
jb302@27: \backslash
jb302@27: bigskip
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: The remainder of this report is split into three parts, one for each component
jb302@27:  of the project, and will attempt to demonstrate the design and usage of
jb302@27:  each of these components.
jb302@27:  
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: \begin_inset Newpage newpage
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Part
jb302@26: Assembler
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: The assembler is written in pure Python 2 using only the standard library.
jb302@26:  It assembles the assembly the language described in the ELB816 specification
jb302@26:  with a few minor differences.
jb302@26:  These differences are:
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Itemize
jb302@26: In-line arithmetic must be wrapped in curved brackets eg.
jb302@26:  start with '(' and end with ')'.
jb302@26:  This is a limitation of the design of the program and to change it would
jb302@26:  require a large amount of code to be re-written.
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Itemize
jb302@26: The only directives that have been implemented are 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: ORG
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26: , 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: EQU
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26: , 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: DB
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  and 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: DS
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26: .
jb302@26:  The other directives listed in the specification have not been implemented,
jb302@26:  but there omission is only due to time constraints and they could easily
jb302@26:  be implemented in a later version.
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Itemize
jb302@26: Macros have not been implemented also due to time constraints.
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: The assembler consists of two files: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Itemize
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: language.py
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  which contains the language definition in an index and some functions to
jb302@26:  help encode instructions.
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Itemize
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: assembler.py
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  which contains the first and second pass functions and handles opening
jb302@26:  source files and writing binary files.
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@27: The following sections details the design and behavior of the assembler.
jb302@26:  However it must be noted that these are abstract and high level descriptions
jb302@26:  that do not fully explain minor routines, but give an overview of the entire
jb302@26:  process.
jb302@26:  The full source code is attached in the Appendix and should be referenced
jb302@26:  for a deeper understanding of the program's operation.
jb302@27:  The final section is a short programmers manual demonstrating the assembler's
jb302@27:  features.
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: \begin_inset Newpage newpage
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Section
jb302@26: Data Structures
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Itemize
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: reserved arguments
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: This structure contains a list of string representations of the reserved
jb302@26:  word arguments for the instruction set.
jb302@26:  These all equate to registers or register pointers.
jb302@26:  The full list is as follows:
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily},captionpos=b,frame=tb,framexbottommargin=1em,framextopmargin=1em,keywordstyle={\color{blue}},tabsize=4"
jb302@26: inline false
jb302@26: status open
jb302@26: 
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jb302@26: 
jb302@26: a, c, bs, ie, flags, 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: r0, r1, r2, r3, 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: dptr, dpl, dph,  
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: sp, sph, spl,
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: @a+pc, @a+dptr, @dptr
jb302@26: \end_layout
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jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
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jb302@26: 
jb302@26: relative instructions
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: This structure contains a list of string representations of the mnemonics
jb302@26:  of instructions that use relative addressing.
jb302@26:  The full list is as follows:
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily},captionpos=b,frame=tb,framexbottommargin=1em,framextopmargin=1em,keywordstyle={\color{blue}},tabsize=4"
jb302@26: inline false
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: djnz, cjne, sjmp, jz,
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: jnz, jc, jnc, jpo, 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: jpe, js, jns
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
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jb302@26: \begin_layout Itemize
jb302@26: \begin_inset listings
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jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: instruction index
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: This structure contains an index of all possible instructions in the instruction
jb302@26:  set, along with the the corresponding opcode and instruction width.
jb302@26:  This is implemented using a combination of Python's dictionary, tuple and
jb302@26:  list objects.
jb302@26:  Its structure is demonstrated below:
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily},captionpos=b,frame=tb,framexbottommargin=1em,framextopmargin=1em,keywordstyle={\color{blue}},tabsize=4"
jb302@26: inline false
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@30: mnemonic: (arg type, arg type, ...): [opcode, width]
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: Each mnemonic has an entry in the parent index which returns another index
jb302@26:  of possible argument formats for that mnemonic with their corresponding
jb302@26:  opcode and length.
jb302@26:  Argument types can be either be one of the reserved arguments or one of
jb302@26:  the following values: 
jb302@26: \begin_inset listings
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jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: address
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26: , 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
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jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: pointer
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26: , 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
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jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: data
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  or 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: label
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  .
jb302@26:  Width is represented in number of bytes, ie.
jb302@26:  
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: width = 3
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  means 1 byte of opcode and 2 bytes of arguments.
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Itemize
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
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jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: label index
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: This structure is used to store an index of label definitions.
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Itemize
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: equate index
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: This structure is used to store an index of equated strings.
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: \begin_inset Newpage newpage
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Section
jb302@26: Functions
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Itemize
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: first_pass(source file)
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: This function pre-processes a source file and stores it in a format containing
jb302@26:  the necessary data for the 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: second_pass()
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  function to assemble it.
jb302@26:  It processes labels and 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: EQU
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  directives by storing strings and their corresponding values in indexes
jb302@26:  and replacing any subsequent appearances of the string with the value.
jb302@26:  It prepares 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: ORG
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  and 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: DB
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  statements for the 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: second_pass()
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26: .
jb302@26:  It uses the 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: tokenize()
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  function to determine the argument symbols and operand bit string.
jb302@26:  Finally it uses the 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: instruction index
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  to determine the instruction width.
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Itemize
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: second_pass(asm, label index)
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: This function takes the pre-processed assembly code and 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: label index
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  output by 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: first_pass()
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  as input.
jb302@26:  First it checks for 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: ORG
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  and 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: DB
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  statements and handles them if necessary.
jb302@26:  Then it replaces any labels that were used before they were defined and
jb302@26:  therefore not replaced on by 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: first_pass()
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  .
jb302@26:  It uses the 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: instruction index 
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  to determine the opcode and the width of the instruction, then it writes
jb302@26:  the opcode and operand to the file.
jb302@26:  If the combined width of the opcode and operand is greater than the instruction
jb302@26:  width the function raises an error.
jb302@26:  
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Itemize
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: tokenize(mnemonic, arguments)
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: This function processes an instruction in order to produce a hashable symbol
jb302@26:  that represents the format of its arguments.
jb302@26:  This symbol is used to look up opcodes in the 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: instruction index
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26: .
jb302@26:  It also detects string representations of numbers in the arguments and
jb302@26:  stores a C type struct representation of the operands to be returned along
jb302@26:  with the symbol.
jb302@26:  It does this with the help of the 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: stoi()
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@27:  function and Python's 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: struct
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  module .
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Itemize
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: stoi(string)
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: This function is a general purpose function that is actually used throughout
jb302@26:  the code, although mainly in the 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: tokenize()
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  function.
jb302@26:  It takes a string as an input and tries to convert it to an integer using
jb302@26:  Pythons integer representation syntax.
jb302@26:  It can recognize decimal, octal, hexadecimal and binary numbers which are
jb302@26:  denoted with different prefixes.
jb302@26:  If it receives a string it can not represent as an integer it returns the
jb302@26:  string 'NaN', (Not a Number)
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: \begin_inset ERT
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 
jb302@26: \backslash
jb302@26: bigskip
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: Below is an abstract representation of each functions logical process.
jb302@26:  The 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: first_pass()
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  and 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: second_pass()
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  are represented in pseudo-code, however 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: stoi()
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  and 
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\ttfamily}"
jb302@26: inline true
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: tokenize()
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26:  are more easily understood when represented as flowcharts.
jb302@26:  
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: \begin_inset Newpage newpage
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Subsection
jb302@27: \begin_inset listings
jb302@27: lstparams "basicstyle={\ttfamily}"
jb302@27: inline true
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: first_pass
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\small\ttfamily},captionpos=b,frame=tb,framexbottommargin=3em,framextopmargin=3em,keywordstyle={\color{blue}},language=Python,showstringspaces=false,tabsize=4"
jb302@26: inline false
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: first_pass(source file):
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 	address = 0
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 	for statement in source file:
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		remove comments
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 	
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		for word in statement:
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 			if word is in equate index:
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 				replace word with equated value
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 			else if word is in label index:
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 				replace word with address at label
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 	
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 			if first word == 'org'
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 				address = second word
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 			else if last character of first word == ':':
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 				remove ':'
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 				add word = address to label index
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 				next statement
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 			else if second word == 'equ'
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 				add first word = third word to equate index
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 				next statement
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 	
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		mnemonic = first word
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		arguments = [second word ...
jb302@26:  last word]
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 	
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		symbol, constant = tokenize(arguments)
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		if mnemonic == 'db':
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 			address = address + width of constant
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 			next statement
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26:         width = instruction index[mnemonic][symbol][width]
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		address = address + width
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 	
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		append [mnemonic, argument, symbol, constant] to asm
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 	return asm, label index
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \begin_inset Newpage newpage
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Subsection
jb302@27: \begin_inset listings
jb302@27: lstparams "basicstyle={\ttfamily}"
jb302@27: inline true
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: second_pass
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27:  
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: \begin_inset listings
jb302@26: lstparams "basicstyle={\small\ttfamily},breaklines=true,captionpos=b,frame=tb,framexbottommargin=3em,framextopmargin=3em,keywordstyle={\color{blue}},language=Python,tabsize=4"
jb302@26: inline false
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: second_pass(file, asm, label index):
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 	address = 0
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 	for line in asm:
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		file offset = address
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		mnemonic, arguments, symbol, constant = line
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 	
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		if mnemonic == 'org':
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 			address = first argument
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 			next line
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		else if mnemonic == 'db':
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 			write constant to file
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 			address = address + width of constant
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 			next line
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 	
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		for argument in arguments:
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 			if argument is a label:
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 				replace argument with address at label
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 				symbol, data = tokenize(argument)
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 				append data to constant
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 	
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		op, width = instruction index[mnemonic][symbol]
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 	
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		write op to file
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		if width of constant - width + 1 > 0:
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 			raise error
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 		else if:
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 			write constant to file
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 			address = address.+ width
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 	
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 	return file
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \begin_inset Newpage newpage
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Subsection
jb302@27: \begin_inset listings
jb302@27: lstparams "basicstyle={\ttfamily}"
jb302@27: inline true
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: tokenize
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: \begin_inset ERT
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 
jb302@26: \backslash
jb302@26: bigskip
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: \begin_inset Graphics
jb302@26: 	filename /home/jmz/qm/ede/doc/images/assembler/tokenize.svg
jb302@27: 	scale 57
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: \begin_inset Newpage newpage
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Subsection
jb302@27: \begin_inset listings
jb302@27: lstparams "basicstyle={\ttfamily}"
jb302@27: inline true
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: stoi
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27:  
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: \begin_inset ERT
jb302@26: status open
jb302@26: 
jb302@26: \begin_layout Plain Layout
jb302@26: 
jb302@26: 
jb302@26: \backslash
jb302@26: bigskip
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Description
jb302@26: \begin_inset Graphics
jb302@26: 	filename /home/jmz/qm/ede/doc/images/assembler/stoi.svg
jb302@26: 	scale 70
jb302@26: 
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Standard
jb302@26: \begin_inset Newpage newpage
jb302@26: \end_inset
jb302@26: 
jb302@26: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \begin_layout Section
jb302@27: Assembly language manual
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: \begin_inset Newpage newpage
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Part
jb302@27: Emulator
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Section
jb302@27: Core microprocessor emulation
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: The core of the emulator is written in C using only standard libraries.
jb302@27:  It executes the machine code output by the assembler according to the ELB816
jb302@27:  specification.
jb302@27:  It consists of the following files:
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Itemize
jb302@27: \begin_inset listings
jb302@27: lstparams "basicstyle={\ttfamily}"
jb302@27: inline true
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: iset.c
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27:  and 
jb302@27: \begin_inset listings
jb302@27: lstparams "basicstyle={\ttfamily}"
jb302@27: inline true
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: iset.h
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: These files contain the emulator instruction functions and function look-up
jb302@27:  table.
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Itemize
jb302@27: \begin_inset listings
jb302@27: lstparams "basicstyle={\ttfamily}"
jb302@27: inline true
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: mem.c
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27:  and 
jb302@27: \begin_inset listings
jb302@27: lstparams "basicstyle={\ttfamily}"
jb302@27: inline true
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: mem.h
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: These files contain the emulators memory structure and memory access functions.
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Itemize
jb302@27: \begin_inset listings
jb302@27: lstparams "basicstyle={\ttfamily}"
jb302@27: inline true
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: emu.c
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: This file contains the program's 
jb302@27: \begin_inset listings
jb302@27: lstparams "basicstyle={\ttfamily}"
jb302@27: inline true
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: main()
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27:  function.
jb302@27:  It initializes the emulator and executes the programs fetch/decode/execute
jb302@27:  cycle.
jb302@27:  
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: \begin_inset ERT
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: 
jb302@27: \backslash
jb302@27: bigskip
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: Below is a high level description of the content of each of these files
jb302@27:  which should demonstrate how the emulator works.
jb302@27:  There is also a large amount of material relevant to the emulator's design
jb302@27:  in the appendix, which will be referenced when applicable.
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Subsection
jb302@27: \begin_inset listings
jb302@27: lstparams "basicstyle={\ttfamily}"
jb302@27: inline true
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: iset.c
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27:  and 
jb302@27: \begin_inset listings
jb302@27: lstparams "basicstyle={\ttfamily}"
jb302@27: inline true
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: iset.h
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: Each mnemonic in the ELB816 instruction set has a function defined in these
jb302@27:  files.
jb302@27:  Each function is responsible for execution of all the instructions that
jb302@27:  use its corresponding mnemonic.
jb302@27:  The function look-up table is an array of pointers to these functions,
jb302@27:  where a pointer's position in the list corresponds to the opcode of the
jb302@27:  instruction to be executed.
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: \begin_inset ERT
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: 
jb302@27: \backslash
jb302@27: bigskip
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: \begin_inset Newpage newpage
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Subsection
jb302@27: \begin_inset listings
jb302@27: lstparams "basicstyle={\ttfamily}"
jb302@27: inline true
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: mem.c
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27:  and 
jb302@27: \begin_inset listings
jb302@27: lstparams "basicstyle={\ttfamily}"
jb302@27: inline true
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: mem.h
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: The figures bellow illustrate the emulator's memory layout as defined in
jb302@27:  the 
jb302@27: \begin_inset listings
jb302@27: lstparams "basicstyle={\ttfamily}"
jb302@27: inline true
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: mem.h
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27:  header file.
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: \begin_inset ERT
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: 
jb302@27: \backslash
jb302@27: bigskip
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: \begin_inset listings
jb302@27: lstparams "basicstyle={\ttfamily}"
jb302@27: inline true
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: mem.c
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27:  contains functions that can be used to access this memory from the rest
jb302@27:  of the code.
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: \begin_inset Newpage newpage
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Subsection
jb302@27: \begin_inset listings
jb302@27: lstparams "basicstyle={\ttfamily}"
jb302@27: inline true
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: emu.c
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: This file contains the emulator's set-up and control procedures.
jb302@27:  It includes all of the projects header files and controls the execution
jb302@27:  of the functions contained in them.
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: \begin_inset ERT
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: 
jb302@27: \backslash
jb302@27: bigskip
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: It first executes a number of initialization procedures and then passes
jb302@27:  control over to the main fetch/decode/execute cycle.
jb302@27:  This procedure is shown below as a flowchart.
jb302@27:  To understand this it you must be familiar with C's function pointer syntax.
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: \begin_inset ERT
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: 
jb302@27: \backslash
jb302@27: bigskip
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: \begin_inset ERT
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: 
jb302@27: \backslash
jb302@27: centerline{
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \begin_inset Graphics
jb302@27: 	filename /home/jmz/qm/ede/doc/images/emulator/fetch_decode_exe.svg
jb302@27: 	scale 70
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \begin_inset ERT
jb302@27: status open
jb302@27: 
jb302@27: \begin_layout Plain Layout
jb302@27: 
jb302@27: }
jb302@27: \end_layout
jb302@27: 
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: \begin_inset Newpage newpage
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Section
jb302@27: Peripherals
jb302@27: \end_layout
jb302@27: 
jb302@27: \begin_layout Standard
jb302@27: \begin_inset Newpage newpage
jb302@27: \end_inset
jb302@27: 
jb302@27: 
jb302@26: \end_layout
jb302@26: 
jb302@26: \end_body
jb302@26: \end_document