Rcomp-kaniw
Rcomp-kaniw is a 4-bit computer project in the town of File:Kaniw flag Kaniw, Ukraine. The machine has been allocated a 2x3 chunk area on the border with the neighbouring town of Cherkassy.
Components
Buses
DataBus 1
Purpose: Loads Data into Arithmetic/Bitwise components.
Size: 4-bit
Writes to: Adder 1, Adder 2, Multiplier, 3-function Bitwise
Reads from: Register 1, Register 2, Register 3, Register 4
DataBus 2
Purpose: Loads Data into Arithmetic/Bitwise components.
Size: 4-bit
Writes to: Adder 1, Adder 2, Multiplier, 3-function Bitwise
Reads from: Register 1, Register 2, Register 3, Register 4
CalcBus 1
Purpose: Loads Data from Arithmetic/Bitwise components to Registers
Writes to: Register 1, Register 2, Register 3, Register 4
Reads from: Adder 1, Adder 2, Multiplier, 3-function Bitwise
==== condition bus
Purpose: Holds a 1 bit value if the previous condition operation was true (==, <, >)
Leads to: Program counter (not written)
Reads from: Comparator
Arithmetic
Adder 1: (CCA design, 4-bit)
Adder 2: (CCA design, 4-bit)
Multiplier: (standard design, 4-bit)
3-function Bitwise: (MUX + AND + OR + XOR gates, 4-bit)
Storage
Register A: (Index: 00, Capacity: 4-bit)
Register B: (Index: 01, Capacity: 4-bit)
Register C: (Index: 10, Capacity: 4-bit)
Register D: (Index : 11, Capacity: 4-bit)
Comparator
Equal to (==): (4-bit)
Greater Than (>): (4-bit)
Less Than (<): (4-bit)
Functions
ALU FUNCTIONS
0: Load DataBus 1 into Adder 1 as input A
1: Load DataBus 2 into Adder 1 as input B
2: Load DataBus 1 into Adder 2 as input A
3: Load DataBus 2 into Adder 2 as input B
4: Load DataBus 1 into Multiplier as input A
5: Load DataBus 2 into Multiplier as input B
6: Load DataBus 1 into Bitwise_Calculator as input A
7: Load Databus 2 into Bitwise_Calculator as input B
8: Run operation: Adder 1 (loads output into CalcBus 1)
9: Run operation: Adder 2 (loads output into CalcBus 1)
A: Run operation: Adder 1 as negative operation (loads output into CalcBus 1)
B: Run operation: Adder 2 as negative operation (loads output into CalcBus 1)
C: Run operation Multiplier (loads output into CalcBus 1)
D: Run operation Bitwise_Calculator as & (and) operation (loads output into CalcBus 1)
E: Run operation Bitwise_Calculator as ^ (xor) operation (loads output into CalcBus 1)
F: Run operation Bitwise_Calculator as | (or) operation (loads output into CalcBus 1)
RAM FUNCTIONS
0: Write USERINPUT on Register 1
1: Write USERINPUT on Register 2
2: Write USERINPUT on Register 3
3: Write USERINPUT on Register 4
4: Read Register 1 into DataBus 1
5: Read Register 1 into DataBus 2
6: Read Register 2 into DataBus 1
7: Read Register 2 into DataBus 2
8: Read Register 3 into DataBus 1
9: Read Register 3 into DataBus 2
A: Read Register 4 into DataBus 1
B: Read Register 4 into DataBus 2
C: Write CalcBus 1 on Register 1
D: Write CalcBus 1 on Register 2
E: Write CalcBus 1 on Register 3
F: Write CalcBus 1 on Register 4
PROGRAM RUNNER FUNCTIONS
REGULAR
0X: Runs the ALU function, where X is the hexidecimal of the ALU function index.
1X: Runs the RAM function, where X is the hexidecimal of the RAM function index.
2-: Does nothing in this clock cycle, practically acts as a wait/sleep.
3XX: Jumps to the instruction at address XX
5XX: Jumps to the instruction if the condition bus is True.
6XX: Jumps to the instruction if the condition bus is False.
COMPARASON
7X: Sets condition bus to True if Register A (index: last 2 bits of X) > Register B (index: first 2 bits of X)
8X: Sets condition bus to True if Register A (index: last 2 bits of X) < Register B (index: first 2 bits of X)
9X: Sets condition bus to True if Register A (index: last 2 bits of X) == Register B (index: first 2 bits of X)
PROGRAM STATUS
A-: Halts the program
B-: Starts the program (this is fired externally, from USERINPUT)
CANVAS
C-: Toggles pixel @ index (index: read from Register 1)
D-: Toggles pixel @ index (index: read from Register 2)
E-: Toggles pixel @ index (index: read from Register 3)
F-: Toggles pixel @ index (index: read from Register 4)
Other Info
When Adder 1 or Adder 2 perform the negation operation, The range of values that a single hexidecimal value can represent shifts from 0 to 15 to -8 to 7, making bit 3 worth -8 and not 8. If bit 3 is still represented as 8, then the negation operation would simply not be true.
Carry-Outs from Adder1 & Adder2 are ignored, as a 5-bit output can't be loaded on a 4-bit bus.
Multipliers can be toggled to either output their first 4 bits, or last 4 bits.
Helpers
DoytschReal: Computer design, Computer construction, Area preperation/Escavation.
Sponsors
DoytschReal: Resources & Components.