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code cleanup and font fix

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This commit is contained in:
Nicholas Orlowsky 2024-01-31 20:57:11 -06:00
parent 044d846313
commit e679a3ce68
10 changed files with 443 additions and 102 deletions
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10
beeper.sv Normal file
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module beeper (
input wire [7:0] sound_timer
);
import "DPI-C" function void set_beep(bit beep);
always_comb begin
set_beep(sound_timer > 0);
end
endmodule

54
chip8.sv Normal file
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module chip8 (
input wire clk_in
);
bit [31:0] vram [0:2047];
bit [7:0] memory [0:4095];
bit keyboard [15:0];
bit [7:0] sound_timer;
bit [15:0] program_counter;
int cycle_counter;
bit [7:0] random_number;
beeper beeper (sound_timer);
cpu cpu (memory, clk_in, keyboard, random_number, cycle_counter, program_counter, vram, sound_timer);
gpu gpu (vram);
keyboard kb (clk_in, keyboard);
rng randy (clk_in, program_counter, keyboard, cycle_counter, random_number);
rom_loader loader (memory);
initial begin
bit [7:0] fontset [79:0] = {
8'hF0, 8'h90, 8'h90, 8'h90, 8'hF0, // 0
8'h20, 8'h60, 8'h20, 8'h20, 8'h70, // 1
8'hF0, 8'h10, 8'hF0, 8'h80, 8'hF0, // 2
8'hF0, 8'h10, 8'hF0, 8'h10, 8'hF0, // 3
8'h90, 8'h90, 8'hF0, 8'h10, 8'h10, // 4
8'hF0, 8'h80, 8'hF0, 8'h10, 8'hF0, // 5
8'hF0, 8'h80, 8'hF0, 8'h90, 8'hF0, // 6
8'hF0, 8'h10, 8'h20, 8'h40, 8'h40, // 7
8'hF0, 8'h90, 8'hF0, 8'h90, 8'hF0, // 8
8'hF0, 8'h90, 8'hF0, 8'h10, 8'hF0, // 9
8'hF0, 8'h90, 8'hF0, 8'h90, 8'h90, // A
8'hE0, 8'h90, 8'hE0, 8'h90, 8'hE0, // B
8'hF0, 8'h80, 8'h80, 8'h80, 8'hF0, // C
8'hE0, 8'h90, 8'h90, 8'h90, 8'hE0, // D
8'hF0, 8'h80, 8'hF0, 8'h80, 8'hF0, // E
8'hF0, 8'h80, 8'hF0, 8'h80, 8'h80 // F
};
// Load fontset into memory
for(int i = 0; i < 80; i++) begin
memory[i] = fontset[79-i];
end
// Initialize keyboard bits
for(int i = 0; i < 15; i++) begin
keyboard[i] = 0;
end
end
endmodule

301
cpu.sv Normal file
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@ -0,0 +1,301 @@
module cpu(
output bit [7:0] memory [0:4095],
input wire clk_in,
input wire keyboard [15:0],
input wire [7:0] random_number,
output int cycle_counter,
output wire [15:0] program_counter,
output wire [31:0] vram [0:2047],
output wire [7:0] sound_timer
);
bit halt;
int watch_key;
logic [15:0] stack [0:15];
logic [15:0] index_reg;
logic [3:0] stack_pointer;
logic [7:0] registers [0:15];
logic [15:0] opcode;
logic [7:0] delay_timer;
logic [15:0] scratch;
logic [15:0] scratch2;
logic [7:0] scratch_8;
logic [7:0] scratch_82;
logic [31:0] x_cord;
logic [31:0] y_cord;
logic [7:0] size;
logic [31:0] screen_pixel;
logic [7:0] sprite_pixel;
// Initialize CPU
initial begin
halt = 0;
watch_key = 255;
sound_timer = 0;
delay_timer = 0;
cycle_counter = 0;
program_counter = 'h200;
stack_pointer = 4'b0000;
end
always_ff @(posedge clk_in) begin
opcode = {memory[program_counter+0], memory[program_counter+1]};
$display("HW : opcode is 0x%h (%b)", opcode, opcode);
$display("HW : PC %0d 0x%h", program_counter, program_counter);
if (cycle_counter % 20 == 0) begin
if (delay_timer > 0)
delay_timer--;
if (sound_timer > 0)
sound_timer--;
end
casez(opcode)
'h00E0: begin
$display("HW : INSTR CLS");
for(int i = 0; i < 2048; i++) begin
vram[i] = 0;
end
end
'h00EE: begin
$display("HW : INSTR RET");
stack_pointer--;
program_counter = stack[stack_pointer];
end
'h0???: $display("HW : INSTR SYS addr (Treating as NOP)");
'h1???: begin
$display("HW : INSTR JP addr");
program_counter = (opcode & 'h0FFF) - 2;
end
'h2???: begin
$display("HW : INSTR CALL addr");
stack[stack_pointer] = program_counter;
stack_pointer++;
program_counter = (opcode & 'h0FFF) - 2;
end
'h3???: begin
$display("HW : INSTR SE Vx, byte");
scratch = (opcode & 'h00FF);
if (scratch[7:0] == registers[(opcode & 'h0F00) >> 8]) begin
program_counter += 2;
end
end
'h4???: begin
$display("HW : INSTR SNE Vx, byte");
scratch = (opcode & 'h00FF);
if (scratch[7:0] != registers[(opcode & 'h0F00) >> 8]) begin
program_counter += 2;
end
end
'h5??0: begin
$display("HW : INSTR SE Vx, Vy");
if (registers[(opcode & 'h00F0) >> 4] == registers[(opcode & 'h0F00) >> 8]) begin
program_counter += 2;
end
end
'h6???: begin
$display("HW : INSTR LD Vx, byte");
scratch = (opcode & 'h00FF);
registers[(opcode & 'h0F00) >> 8] = scratch[7:0];
end
'h7???: begin
$display("HW : INSTR ADD Vx, byte");
scratch = (opcode & 'h00FF);
registers[(opcode & 'h0F00) >> 8] += scratch[7:0];
end
'h8??0: begin
$display("HW : INSTR LD Vx, Vy");
registers[(opcode & 'h0F00) >> 8] = registers[(opcode & 'h00F0) >> 4];
end
'h8??1: begin
$display("HW : INSTR OR Vx, Vy");
registers[(opcode & 'h0F00) >> 8] |= registers[(opcode & 'h00F0) >> 4];
registers[15] = 0;
end
'h8??2: begin
$display("HW : INSTR AND Vx, Vy");
registers[(opcode & 'h0F00) >> 8] &= registers[(opcode & 'h00F0) >> 4];
registers[15] = 0;
end
'h8??3: begin
$display("HW : INSTR XOR Vx, Vy");
registers[(opcode & 'h0F00) >> 8] ^= registers[(opcode & 'h00F0) >> 4];
registers[15] = 0;
end
'h8??4: begin
$display("HW : INSTR ADD Vx, Vy");
scratch_8 = registers[(opcode & 'h0F00) >> 8];
registers[(opcode & 'h0F00) >> 8] += registers[(opcode & 'h00F0) >> 4];
registers[15] = {7'b0000000, scratch_8 > registers[(opcode & 'h0F00) >> 8]};
end
'h8??5: begin
$display("HW : INSTR SUB Vx, Vy");
scratch_8 = registers[(opcode & 'h0F00) >> 8];
registers[(opcode & 'h0F00) >> 8] -= registers[(opcode & 'h00F0) >> 4];
registers[15] = {7'b0000000, scratch_8 >= registers[(opcode & 'h0F00) >> 8]};
end
'h8??6: begin
$display("HW : INSTR SHR Vx {, Vy}");
scratch_8 = registers[(opcode & 'h0F00) >> 8];
registers[(opcode & 'h0F00) >> 8] = registers[(opcode & 'h00F0) >> 4]>> 1;
registers[15] = {7'b0000000, ((scratch_8 & 8'h01) == 8'h01)};
end
'h8??7: begin
$display("HW : INSTR SUBN Vx, Vy");
scratch_8 = registers[(opcode & 'h00F0) >> 4];
scratch_82 = registers[(opcode & 'h0F00) >> 8];
registers[(opcode & 'h0F00) >> 8] = registers[(opcode & 'h00F0) >> 4] - registers[(opcode & 'h0F00) >> 8];
registers[15] = {7'b0000000, (scratch_8 >= scratch_82)};
end
'h8??E: begin
$display("HW : INSTR SHL Vx {, Vy}");
scratch_8 = registers[(opcode & 'h0F00) >> 8];
registers[(opcode & 'h0F00) >> 8] = registers[(opcode & 'h00F0) >> 4]<< 1;
registers[15] = {7'b0000000, (scratch_8[7]) };
end
'h9??0: begin
$display("HW : INSTR SNE Vx, Vy");
if (registers[(opcode & 'h00F0) >> 4] != registers[(opcode & 'h0F00) >> 8]) begin
program_counter += 2;
end
end
'hA???: begin
$display("HW : INSTR LD I, addr");
index_reg = (opcode & 'h0FFF);
end
'hb???: begin
$display("HW : INSTR JP V0, addr");
program_counter = {8'h00, registers[0]} + (opcode & 'h0FFF) - 2;
end
'hc???: begin
$display("HW : RND Vx, addr");
// TODO: use a real RNG module, this is not synthesizeable
scratch = {8'h00, random_number} % 16'h0100;
scratch2 = (opcode & 'h00FF);
registers[(opcode & 'h0F00) >> 8] = scratch[7:0] & scratch2[7:0];
end
'hD???: begin
$display("HW : INSTR DRW Vx, Vy, nibble");
if (cycle_counter % 20 != 0) begin
halt = 1;
end else begin
halt = 0;
x_cord = {24'h000000, registers[(opcode & 'h0F00) >> 8]};
y_cord = {24'h000000, registers[(opcode & 'h00F0) >> 4]};
x_cord %= 64;
y_cord %= 32;
scratch = (opcode & 'h000F);
size = scratch[7:0];
registers[15] = 0;
for (int r = 0; r < size; r++) begin
for (int c = 0; c < 8; c++) begin
if (r + y_cord >= 32 || x_cord + c >= 64)
continue;
screen_pixel = vram[((r + y_cord) * 64) + (x_cord + c)];
sprite_pixel = memory[{16'h0000, index_reg} + r] & ('h80 >> c);
if (|sprite_pixel) begin
if (screen_pixel == 32'hFFFFFFFF) begin
registers[15] = 1;
end
vram[((r + y_cord) * 64) + (x_cord + c)] ^= 32'hFFFFFFFF;
end
end
end
end
end
'hE?9E: begin
$display("HW : INSTR SKP Vx");
if (keyboard[{registers[(opcode & 'h0F00) >> 8]}[3:0]] == 1) begin
program_counter += 2;
end
end
'hE?A1: begin
$display("HW : INSTR SNE Vx");
if (keyboard[{registers[(opcode & 'h0F00) >> 8]}[3:0]] != 1) begin
program_counter += 2;
end
end
'hF?07: begin
$display("HW : INSTR LD Vx, DT");
registers[(opcode & 'h0F00) >> 8] = delay_timer;
end
'hF?0A: begin
$display("HW : INSTR LD Vx, K");
halt = 1;
for(int i = 0; i < 16; i++) begin
if (watch_key == 255) begin
if (keyboard[i]) begin
watch_key = i;
end
end else begin
if (!keyboard[watch_key]) begin
halt = 0;
watch_key = 255;
end
end
end
end
'hF?15: begin
$display("HW : INSTR LD DT, Vx");
delay_timer = registers[(opcode & 'h0F00) >> 8];
end
'hF?18: begin
$display("HW : INSTR LD ST, Vx");
sound_timer = registers[(opcode & 'h0F00) >> 8];
end
'hF?1E: begin
$display("HW : INSTR ADD I, Vx");
index_reg = index_reg + {8'h00, registers[(opcode & 'h0F00) >> 8]};
end
'hF?29: begin
$display("HW : INSTR LDL F, Vx");
index_reg = registers[(opcode & 'h0F00) >> 8] * 5;
end
'hF?33: begin
$display("HW : INSTR LD B, Vx");
scratch = {8'h00, registers[(opcode & 'h0F00) >> 8]};
scratch2 = scratch % 10;
memory[index_reg + 2] = scratch2[7:0];
scratch /= 10;
scratch2 = scratch % 10;
memory[index_reg + 1] = scratch2[7:0];
scratch /= 10;
scratch2 = scratch % 10;
memory[index_reg + 0] = scratch2[7:0];
end
'hF?55: begin
$display("HW : INSTR LD [I], Vx");
scratch = (opcode & 'h0F00) >> 8;
for (bit [7:0] i8 = 0; i8 <= scratch[7:0]; i8++) begin
scratch2 = index_reg + {8'h00, i8};
memory[scratch2[11:0]] = registers[i8[3:0]];
end
index_reg++;
end
'hF?65: begin
$display("HW : INSTR LD Vx, [I]");
scratch = (opcode & 'h0F00) >> 8;
for (bit [7:0] i8 = 0; i8 <= scratch[7:0]; i8++) begin
scratch2 = index_reg + {8'h00, i8};
registers[i8[3:0]] = memory[scratch2[11:0]];
end
index_reg++;
end
default: $display("HW : ILLEGAL INSTRUCTION");
endcase
if (!halt)
program_counter += 2;
cycle_counter++;
end
endmodule

15
gpu.sv Normal file
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@ -0,0 +1,15 @@
module gpu (
input wire [31:0] vram [0:2047]
);
import "DPI-C" function void init_screen();
import "DPI-C" function void draw_screen(logic [31:0] vram [0:2047]);
initial begin
init_screen();
end
always_comb begin
draw_screen(vram);
end
endmodule

15
keyboard.sv Normal file
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@ -0,0 +1,15 @@
module keyboard (
input wire clk_in,
output bit keyboard [15:0]
);
import "DPI-C" function bit [7:0] get_key();
always_ff @(posedge clk_in) begin
bit[7:0] keyval = get_key();
if (&keyval != 1) begin
keyboard[keyval[3:0]] = keyval[7];
end
end
endmodule

4
makefile
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@ -5,10 +5,10 @@ lint:
verilator --lint-only --timing *.sv
build: lint
verilator --cc --exe --build --timing -j 0 --top-module yayacemu *.sv yayacemu.cpp -CFLAGS "${SDL_CFLAGS}" -LDFLAGS "${SDL_LDFLAGS}" && clear
verilator --cc --exe --build --timing -j 0 --top-module chip8 *.sv yayacemu.cpp -CFLAGS "${SDL_CFLAGS}" -LDFLAGS "${SDL_LDFLAGS}" && clear
run: build
obj_dir/Vyayacemu ${ROM_FILE}
obj_dir/Vchip8 ${ROM_FILE}
clean:
rm -rf obj_dir

19
rng.sv Normal file
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@ -0,0 +1,19 @@
module rng (
input wire clk_in,
input wire [15:0] pc,
input bit keyboard [15:0],
input int cycle_counter,
output bit [7:0] rand_bit
);
bit [7:0] last;
always_ff @(posedge clk_in) begin
for (int i = 0; i < 8; i++) begin
rand_bit[i] ^= ~keyboard[i] ? cycle_counter[i] : cycle_counter[7-i];
rand_bit[i] ^= (cycle_counter % 7) == 0 ? pc[i] : ~pc[i];
rand_bit[i] ^= keyboard[i+7] ? ~last[i] : last[i];
end
last = rand_bit;
end
endmodule

12
rom_loader.sv
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@ -1,24 +1,18 @@
module rom_loader (
output bit [7:0] memory [0:4095],
output logic rom_ready
output bit [7:0] memory [0:4095]
);
import "DPI-C" function int load_rom();
import "DPI-C" function bit [7:0] get_next_instr();
import "DPI-C" function void close_rom();
int rom_size;
int i;
initial begin
rom_size = load_rom();
int rom_size = load_rom();
$display("HW : ROM size is %0d bytes (%0d bits) (%0d instructions)", rom_size, rom_size * 8, rom_size / 2);
for (i = 0; i < rom_size; i++) begin
for (int i = 0; i < rom_size; i++) begin
memory['h200 + i] = get_next_instr();
end
close_rom();
$display("HW : ROM loaded successfully");
$finish;
rom_ready = 1;
end
endmodule

50
yayacemu.cpp
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@ -1,11 +1,9 @@
#include "svdpi.h"
#include "Vyayacemu__Dpi.h"
#include <stdio.h>
#include "Vchip8__Dpi.h"
#include <iostream>
#include <memory.h>
#include "Vyayacemu.h"
#include "Vchip8.h"
#include "verilated.h"
#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
#include <SDL2/SDL_quit.h>
@ -34,11 +32,11 @@ void init_screen() {
texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGBA8888,
SDL_TEXTUREACCESS_STREAMING,
SCREEN_WIDTH, SCREEN_HEIGHT);
printf("INF_EMU: Screen initialized\n");
std::cout << "INF_EMU: Screen initialized" << '\n';
}
void set_beep(const svBit beep) {
if (beep > 0)
if (beep == 1)
SDL_SetTextureColorMod(texture, 255, 0, 0);
else
SDL_SetTextureColorMod(texture, 255, 255, 255);
@ -49,28 +47,27 @@ void draw_screen(const svLogicVecVal* vram) {
for(int i = 0; i < SCREEN_WIDTH * SCREEN_HEIGHT; i++) {
screen[i] = vram[i].aval;
}
SDL_UpdateTexture(texture, NULL, screen,
sizeof(screen[0]) * SCREEN_WIDTH);
SDL_UpdateTexture(texture, NULL, screen, sizeof(screen[0]) * SCREEN_WIDTH);
SDL_RenderClear(renderer);
SDL_RenderCopy(renderer, texture, NULL, NULL);
SDL_RenderPresent(renderer);
printf("INF_EMU: Drawing Frame\n");
free(screen);
std::cout << "INF_EMU: Drawing Frame" << '\n';
}
int load_rom() {
printf("INF_EMU: Loading ROM %s\n", rom_name);
std::cout << "INF_EMU: Loading ROM " << rom_name << '\n';
rom_file = fopen(rom_name, "r");
if (rom_file == NULL) {
printf("INF_EMU: Error reading ROM file. Panicing.\n");
std::cout << "INF_EMU: Error reading ROM file. Panicing." << '\n';
exit(1);
}
fseek(rom_file, 0L, SEEK_END);
int rom_size = ftell(rom_file);
fseek(rom_file, 0L, SEEK_SET);
printf("INF_EMU: ROM size is %d bytes\n", rom_size);
std::cout << "INF_EMU: ROM size is %d bytes " << rom_size << '\n';
return rom_size;
}
@ -83,13 +80,10 @@ void close_rom() {
fclose(rom_file);
}
int get_num() {
return 1;
}
svBitVecVal get_key() {
SDL_Event event;
uint8_t down = 0;
while(SDL_PollEvent(&event)) {
switch(event.type) {
case SDL_KEYDOWN:
@ -142,25 +136,29 @@ svBitVecVal get_key() {
int main(int argc, char** argv) {
if (argc < 2) {
printf("Use: yayacemu [ROM_NAME]");
std::cout << "Use: yayacemu [ROM_NAME]" << '\n';
exit(1);
}
rom_name = argv[1];
VerilatedContext* contextp = new VerilatedContext;
contextp->commandArgs(argc, argv);
Vyayacemu* top = new Vyayacemu{contextp};
//while (!contextp->gotFinish()) {
for (int i = 0; ; i++) {
top->clk_in ^= 1;
top->eval();
Vchip8* dut = new Vchip8{contextp};
while (true) {
dut->clk_in ^= 1;
dut->eval();
usleep(1000000/EMULATION_HZ);
if (SDL_QuitRequested()) {
printf("Received Quit from SDL. Goodbye!\n");
std::cout << "INF_EMU: Received Quit from SDL. Goodbye!" << '\n';
break;
}
}
fflush(stdout);
delete top;
delete dut;
delete contextp;
return 0;
}

65
yayacemu.sv
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@ -1,65 +0,0 @@
module yayacemu (
input wire clk_in
);
wire [31:0] vram [0:2047];
bit [7:0] memory [0:4095];
wire [7:0] registers [0:15];
logic [3:0] stack_pointer;
wire [15:0] stack [0:15];
logic [7:0] delay_timer;
logic [7:0] sound_timer;
bit keyboard [15:0];
int cycle_counter;
bit halt;
int watch_key;
logic [15:0] index_reg;
bit [7:0] rand_num;
logic rom_ready;
logic [15:0] program_counter;
bit [7:0] fontset [79:0];
randomizer randy(clk_in, program_counter, keyboard, cycle_counter, rand_num);
keyboard kb(clk_in, keyboard);
rom_loader rl (memory, rom_ready);
cpu cpu (memory, clk_in, keyboard, rand_num, vram, stack, index_reg, stack_pointer, registers, delay_timer, sound_timer, cycle_counter, program_counter, halt, watch_key);
beeper beeper(sound_timer);
gpu gpu (vram);
int i;
initial begin
fontset = {
8'hF0, 8'h90, 8'h90, 8'h90, 8'hF0, // 0
8'h20, 8'h60, 8'h20, 8'h20, 8'h70, // 1
8'hF0, 8'h10, 8'hF0, 8'h80, 8'hF0, // 2
8'hF0, 8'h10, 8'hF0, 8'h10, 8'hF0, // 3
8'h90, 8'h90, 8'hF0, 8'h10, 8'h10, // 4
8'hF0, 8'h80, 8'hF0, 8'h10, 8'hF0, // 5
8'hF0, 8'h80, 8'hF0, 8'h90, 8'hF0, // 6
8'hF0, 8'h10, 8'h20, 8'h40, 8'h40, // 7
8'hF0, 8'h90, 8'hF0, 8'h90, 8'hF0, // 8
8'hF0, 8'h90, 8'hF0, 8'h10, 8'hF0, // 9
8'hF0, 8'h90, 8'hF0, 8'h90, 8'h90, // A
8'hE0, 8'h90, 8'hE0, 8'h90, 8'hE0, // B
8'hF0, 8'h80, 8'h80, 8'h80, 8'hF0, // C
8'hE0, 8'h90, 8'h90, 8'h90, 8'hE0, // D
8'hF0, 8'h80, 8'hF0, 8'h80, 8'hF0, // E
8'hF0, 8'h80, 8'hF0, 8'h80, 8'h80 // F
};
watch_key = 255;
halt = 0;
for(i = 0; i < 80; i++) begin
memory[i] = fontset[i];
end
for(i = 0; i < 15; i++) begin
keyboard[i] = 0;
end
sound_timer = 0;
delay_timer = 0;
cycle_counter = 0;
program_counter = 'h200;
stack_pointer = 4'b0000;
end
endmodule