Write a PEP/8 machine language simulator that simulates the PEP/8 computer and instruction set for only the following instructions:
computer science
Description
PEP8 SIMULATOR MIDTERM PROJECT
GOAL: Write a PEP/8 machine language simulator that
simulates the PEP/8 computer and instruction set for only the following
instructions:
|
Instruction Specifier |
Instruction |
Addressing Modes |
Status Bits |
|
0000 0000 |
Stop execution |
NA |
|
|
0001 100r |
Bitwise invert r |
NA |
NZ |
|
0001 110r |
Arithmetic shift left r |
NA |
NZVC |
|
0001 111r |
Arithmetic shift right r |
NA |
NZC |
|
0010 000r |
Rotate left r |
NA |
C |
|
0010 001r |
Rotate right r |
NA |
C |
|
0011 0aaa |
Decimal input trap |
d |
NZV |
|
0011 1aaa |
Decimal output trap |
d, i |
|
|
0100 1aaa |
Character input |
d |
|
|
0101 0aaa |
Character output |
d, i |
|
|
0111 raaa |
Add to r |
d, i |
NZVC |
|
1000 raaa |
Subtract from r |
d, i |
NZVC |
|
1001 raaa |
Bitwise AND to r |
d, i |
NZ |
|
1010 raaa |
Bitwise OR to r |
d, i |
NZ |
|
1100 raaa |
Load r from memory |
d, i |
NZ |
|
1101 raaa |
Load byte from memory |
d, i |
NZ |
|
1110 raaa |
Store r to memory |
d |
|
|
1111 raaa |
Store byte r to memory |
d |
|
Here are some
specifics.
- Use an
array to represent the memory.
- Use
variables or arrays for the PEP8 registers. I recommend putting it all
into a structure. I also recommend using an array of 16 bit values for A,
X, PC, SP so that you can use the r bit from the instructions to
point directly to A or X. You do NOT
have to include the Status bits.
- Use
unions of structures to break up the registers and instructions into the
correct bits (for example, use a structure that can be unioned to break up
the 8 bit specifier into the following bit combos (4, 1, 3), (5, 3), (7,
1), (8). This will allow you to instantly extract the instruction,
register and addressing modes from each instruction. Also use a union to
break up the 16 bit operand into two 8 bit values.
- Have
the instructions be inputted either through the command line or better
yet, through a file, in the following format for each instruction:
- 6
Hexadecimal characters per instruction
- After
each instruction in the program is executed, output the PEP8 machine
register values.
