1,885
edits
Changes
no edit summary
[[Category:SPO600 Labs- Retired]]{{Admon/important|This lab is not used in the current semester.|Please refer to the other labs in the [[:Category:SPO600 Labs|SPO600 Labs]] category.}} {{Admon/lab|Purpose of this Lab|In this lab, you will write code with arithmetic/math in [[6502]] assembly language, in preparation for learning more complex x86_64 and AArch64 assembly language.}}
== Resources ==
** The last key pressed is stored in memory location $FF. Clear this location (to 0) after reading it. Printable characters, ENTER, and Backspace are represented by their ASCII codes; the arrow keys are represented by the codes $80-$83 (up/right/down/left).
* Random number generatorFixed-pointA fixed-point value is encoded the same as an integer, except that some of the bits are fractional -- they're considered to be to the right of the "binary point" (binary version of "decimal point" - or more generically, the radix point). For example, binary 000001.00 is decimal 1.0, and 000001.11 is decimal 1.75.An alternative to fixed-point values is integer values in a smaller unit of measurement. For example, some accounting software may use integer values representing cents. For input and display purposes, dollar and cent values are converted to/from cent values.generator
** A random byte is available at memory location $FE.
* Drawing a Line
** To draw a line between two arbitrary points (X<sub>1</sub>,Y<sub>1</sub>)(X<sub>2</sub>,Y<sub>2</sub>) where X<sub>2</sub>-X<sub>1</sub> > Y<sub>2</sub>-Y<sub>1</sub> and all coordinates are positive, calculate the rise/run, then set Y=Y<sub>1</sub> and iterate for X=X<sub>1</sub>:X<sub>2</sub> incrementing Y by the rise/run each step.
** Do something similar with run/rise where X<sub>2</sub>-X<sub>1</sub> < Y<sub>2</sub>-Y<sub>1</sub>
** Suggestion: Use fixed-point math for the rise/run (aka deltaY) value.
=== Setup ===
1. Organize a group of 4-6 students around one of Join the monitor/whiteboard groups in the classroom. Arrange the furniture so that everyone has a comfortable view of the display. 2assigned Breakout Room. Gather these supplies:* HDMI cable* Whiteboard markers
{{Admon/tip|Sharing Results|Decide how group results will be shared between the members of the group. (Suggestion: consider using a git repository).}}
=== Pick an Option ===
==== Option I1: Bouncing Graphic ====
# Create a simple graphic in a square that is 5x5 or 7x7 pixels in size. Use the colours available in the emulator's bitmapped display. The graphic could be a ball, a happy face, a logo, an emoji, or anything else (appropriate!) that you want to use.
# Encode that graphic in bytes using DCB (declare constant byte) instructions.
# Write code to make the graphic bounce around the screen, reflecting off the edges when it hits. Note: for simplicity, it is OK if the object always bounces at 45-degree angles.
# Make the speed keyboard-adjustable (faster/slower) and perturb the object's path once in a while(add a glitch - adjust the angle or nudge the obect by a pixel at random intervals).
Challenge: randomize the starting position, and make the object bounce at angles other than 45 degrees.
==== Option 2: Numeric Display ====
# Create or find (under an appropriate license) the Obtain bitmapped font patterns for the digits 0-9 on an 8x8 pixel matrix.:#* Use [[8x8 Bitmap Patterns for Digits|pre-defined bitmap patterns]], or#* Find alternate patterns on the web, or#* Design your own font patterns# Encode the font patterns for these characters using DCB (declare constant byte) instructionsdirectives.
# Write code to display a 2-digit unsigned decimal number (0-99). The + and - keys should increment and decrement this number.
Challenge: extend the code to suppress leading zeros and display a signed number (-99 to +99).
