To run the program:
- This Simulator will behave badly on unexpected input, so be
careful!
- Press the "New Computer Simulator" button above to get a new
frame
- Press the "Clear Registers" and "Clear Memory" buttons
- Copy and paste the "Sample Program" code below into the
Assembly Code text area
- Press Assemble
- Note the Symbol Table in the "Assembler Messages" panel, and
the generated code in the "Machine Code" panel
- Press "Load Program From Assembler"
- Note the changes in the "Memory" panel
- Easiest is to select ASCII on the Input and Output panels
- Type something in the Input panel
- BE SURE to end the input stream with a "." - a period.
- Press Reset - resets the PC to the start of the program and
clears some of the flags
- Run the program:
- Next T - state by state, approximately clock tick by clock
tick
- Next I - assembly language instruction to instruction
- Run - go until a Halt is encountered or until the Kill
button is pressed
// Sample Program
// loads chars from input stream
// copies them to output stream
// and memory locations starting at 50
// until target char, ECH, encountered
// will infinite loop if
// input stream does not
// end with a . - period
SETPCSTART 10
ORG 10
LDA ECH // calculates 2's comp
CMA // 1's
comp
INC // 2's
comp
STA ECH // stores 2's of target
FST SKI // look for input
BUN FST // no input
CLA //
clear AC
INP //
input to AC
OUT //
ouput char
STA PTR I // store char
ISZ PTR // inc location
ADD ECH // is it target?
SZA // quit
if target
BUN FST // next char
END HLT // quit
ECH HEX 2E // end character "."
PTR HEX 50 // store chars here
END