Altera Nios II Custom Manual do Utilizador descarregar pdf (Página 41)

Appendix A: Custom Instruction Templates A–3

Verilog HDL Custom Instruction Template Example

January 2011 Altera Corporation Nios II Custom Instruction User Guide

Verilog HDL Custom Instruction Template Example

Example A–2 shows a Verilog HDL custom instruction template for an internal

Example A–2. Verilog HDL Custom Instruction Template for Internal Register Logic Type Instruction

// Verilog Custom Instruction Template File for Internal Register Logic

module custominstruction(

clk, // CPU system clock (required for multicycle or extended multicycle)

reset, // CPU master asynchronous active high reset

// (required for multicycle or extended multicycle)

clk_en,// Clock-qualifier (required for multicycle or extended multicycle)

start, // Active high signal used to specify that inputs are valid

// (required for multicycle or extended multicycle)

done, // Active high signal used to notify the CPU that result is valid

// (required for variable multicycle or extended variable multicycle)

n, // N-field selector (required for extended)

dataa, // Operand A (always required)

datab, // Operand B (optional)

a, // Internal operand A index register

b, // Internal operand B index register

c, // Internal result index register

readra,// Read operand A from CPU (otherwise use internal operand A)

readrb, // Read operand B from CPU (otherwise use internal operand B)

writerc,// Write result to CPU (otherwise write to internal result)

result // Result (always required)

);

//INPUTS

inputclk;

inputreset;

inputclk_en;

inputstart;

input[7:0]n;// modify width to match the number of unique operations in the instruction

input[4:0]a;

input[4:0]b;

input[4:0]c;

inputreadra;

inputreadrb;

inputwriterc;

input[31:0]dataa;

input[31:0]datab;

//OUTPUTS

outputdone;

output[31:0]result;

// custom instruction logic (note: external interfaces can be used as well)

// Use the n[7..0] port as a select signal on a multiplexer

// to select the value to feed result[31..0]

endmodule

1 2 ... 36 37 38 39 40 41 42 43 44 45 46 ... 49 50

Comentários a estes Manuais

Sem comentários

Altera Nios II Custom Manual do Utilizador Página 41

Comentários a estes Manuais

Manuais e produtos relacionados com Instrumentos de medida Altera Nios II Custom