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The Visible Computer 8088 1.x

SystemSystem
edited August 9 in Product Comments
imageThe Visible Computer 8088 1.x

TVC, from Software Masters Inc., is an educational tool for teaching assembly language.

Read the full story here

Comments

  • CraigAB69CraigAB69
    There is a fellow on flickr that has the manual. https://www.flickr.com/photos/target_man_2000/54708120539/in/photostream/
    What I know without the manual.

    e_Visible_Computer_8088_Reconstructed_Usage_Notes.txt


    The Visible Computer: 8088 v1.00 – Reconstructed Usage Notes

    These notes are based on hands-on testing of The Visible Computer: 8088 v1.00 in 86Box, strings/disassembly inspection of TVC.EXE, and photographs of the original manual.

    STARTUP

    Start the program from DOS with:

    TVC

    Demo files are loaded from inside TVC at the >> prompt, for example:

    load MOV1.DEM
    load ADD.DEM
    load DIV.DEM

    The .DEM files are lesson/example programs that TVC disassembles and simulates.

    MAIN COMMANDS CONFIRMED SO FAR

    LOAD filename
    Load a .DEM file.

    NEW
    Return the currently loaded demo to its first assembly instruction.

    SIM
    Enter the 8088 simulator.

    STEP n
    Set simulator pause/detail level. Valid values are 0, 1, 2, 3, 4.

    DSCRN
    Redraw/clear the display and place the currently executing assembly instruction near the top of the disassembly window.

    BASE register HEX
    BASE register DEC
    Change the display format of a register without changing its value.
    Examples:
    base ax hex
    base ax dec
    base bx hex

    CALC
    Enter calculator mode.
    It displays something like:
    H:0000
    Typing a digit changes the hexadecimal display.
    Ctrl-C exits calculator mode back to the >> prompt.
    Arithmetic/operator keys have not yet been fully reconstructed.

    SAVE filename
    Confirmed by the original manual. Saves the current program/file to disk.

    Q
    Quit The Visible Computer and return to DOS.

    SIMULATOR MODE

    After entering:

    sim

    the normal >> command prompt is no longer active.

    The original manual confirms these simulator keys:

    Spacebar
    End a pause or request a pause.

    C
    Activate calculator.

    1-9
    Set simulation speed. 1 is fastest.

    Esc or Ctrl-C
    Terminate simulation and return to the monitor/command prompt.

    T, N, I
    Toggle 8088 input-pin signals.

    P
    Output to printer after every instruction.

    STEP LEVELS

    The original manual states that STEP controls how often the simulator pauses while executing an instruction.

    Observed behaviour:

    STEP 0
    Essentially assembly-instruction level. Little or no visible internal stepping.

    STEP 1
    Similar to STEP 0; registers and state update and execution advances to the next assembly instruction.

    STEP 2
    Begins exposing internal CPU activity. Spacebar advances through pauses.

    STEP 3
    Detailed internal operations/register transfers are shown.

    STEP 4
    Maximum pause/detail level.

    Example internal messages include:

    fetch opcode
    transfer: or <-- ip

    For the instruction:

    MOV AX,0CCC

    observed pause counts were:

    STEP 3: 14 presses of Space
    STEP 4: 26 presses of Space

    These pauses are not CPU clock cycles. They are simulation events/internal operations chosen by TVC for teaching purposes.

    SCREEN LAYOUT

    The main register display includes:

    AX BX
    CX DX
    SI DI
    BP SP
    DS SS
    ES CS
    FL IP

    At higher STEP levels TVC also exposes internal state/registers such as:

    EA
    IR
    SR
    X
    OR
    Y
    AD
    Z
    AB
    DB

    The top flag display shows:

    O D I T
    S Z A P C

    The right-hand pane shows the disassembly, with the current instruction highlighted.

    Example:

    cs:0100 mov ax,0CCC
    cs:0103 mov bl,14
    cs:0105 div bl

    DISK/VERSION NOTES

    The Visible Computer: 8088 v1.00 works in 86Box 6.0.

    Version 1.10 uses copy protection. The original TransCopy image contains an unusual protection sector on track 6.0:

    Sector ID: 1
    Size: 256 bytes
    Checksum/CRC: Invalid

    The TC -> 86F conversion preserved this unusual sector, but 86Box still gives:

    Sector not found reading drive A

    when running v1.10.

    Therefore v1.00 is currently the practical version for use in 86Box.

    ORIGINAL MANUAL PHOTOGRAPHS FOUND

    Photographs of the original spiral-bound manual have been located. Visible pages include:

    8-9
    Alternate Numbering Systems

    114-115
    Conditional Jumps

    172-173
    MOVS, REP, and overlapping memory moves

    222-223
    BIOS and DOS services

    238-239
    Writing programs/source syntax

    288-289
    Command Reference including SAVE, SET, SIM, and STEP

    The manual confirms that The Visible Computer is not merely an assembler tutorial. It is an interactive 8088 teaching system that shows assembly execution together with internal processor operations.

    KNOWN COMMANDS / FEATURES STILL TO DOCUMENT

    CLEAR
    DMEM
    ERASE
    DSTAT
    SKIP
    SET
    Search command syntax
    Calculator operator keys
    Meaning of all simulator/internal indicators

    These notes are incomplete and should be treated as a working reconstruction.
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