initial commit

12 files changed, 278 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..1062ad7
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+chip8
diff --git a/Makefile b/Makefile
new file mode 100755
index 0000000..b504d98
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,19 @@
+all: CC=gcc

+win: CC=x86_64-w64-mingw32-gcc

+

+CFLAGS  = -O3 -Wall -std=c99 $(shell pkg-config --cflags ncursesw)

+

+all: BIN = chip8

+win: BIN = chip8.exe

+

+all: executable

+win: executable

+

+all: LDFLAGS  = -lncursesw -ltinfow -lpthread

+win: LDFLAGS  = ./win/pdcurses.a

+

+executable: chip8.c ui.c util.c

+	$(CC) $(CFLAGS) -o $(BIN) chip8.c ui.c util.c $(LDFLAGS)

+

+clean:

+	$(RM) chip8 

diff --git a/chip8.c b/chip8.c
new file mode 100644
index 0000000..c48f543
--- /dev/null
+++ b/chip8.c
@@ -0,0 +1,150 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <arpa/inet.h>
+
+#ifdef _WIN32
+#include <window.h>
+#else
+#include <unistd.h>
+#include <pthread.h>
+#endif
+
+#include "ui.h"
+#include "util.h"
+#include "chip8.h"
+
+#define ROM_FILE "roms/a.ch8"
+
+static void load_rom();
+static void init_vm();
+static void push_top_of_stack(u16 val);
+static void vm_thread(void* v);
+
+chip8_vm vm;
+
+void init_vm() {
+  memset(&vm, 0, sizeof(chip8_vm));
+  vm.PC = 0x200; // start of chip8 programs
+}
+
+void load_rom() {
+  FILE* f = fopen(ROM_FILE, "r");
+  fseek(f, 0, SEEK_END);
+  long fsize = ftell(f);
+  fseek(f, 0, SEEK_SET);
+
+  vm.rom = malloc(fsize + 1);
+  vm.rom_size = 0x200 + fsize;
+  if (fread(vm.rom, 1, fsize, f) != fsize) {
+    printf("err: failed to read rom fully\n");
+    exit(1);
+  }
+
+  fclose(f);
+}
+
+void push_top_of_stack(u16 val) {
+  for (u16 i = vm.SP; i < vm.stack_count; i++) {
+    if (i >= 15) {
+      exit(1);
+    }
+    vm.stack[i+1] = vm.stack[i];
+  }
+  vm.stack[vm.SP] = val;
+}
+
+void vm_thread(void* v) {
+  if (vm.PC > vm.rom_size) {
+    return;
+  }
+
+  // read 2 bytes and convert to big-endian
+  u16 instr = htons(vm.rom[(vm.PC) - 0x1FF]<<8 | vm.rom[(vm.PC) - 0x200]);
+
+  char str[5];
+  sprintf(str, "%x", instr);
+
+  switch (*str) {
+    case '0':
+      if (instr == 0x00E0) {
+        //clearscreen
+      } else if (instr == 0x00EE) {
+        vm.PC = vm.stack[vm.SP--];
+      } 
+      break;
+    case '1':
+      vm.PC = hex_str(str+1);
+      break;
+    case '2':
+      vm.SP++;
+      push_top_of_stack(vm.PC);
+      vm.PC = hex_str(str+1);
+      break;
+    case '3':
+      if (vm.Vx[hex_char(str[1])] == hex_str(str+2)) {
+        vm.PC += 0x2;
+      }
+      break;
+    case '4':
+      if (vm.Vx[hex_char(str[1])] != hex_str(str+2)) {
+        vm.PC += 0x2;
+      }
+      break;
+    case '5':
+      if (vm.Vx[hex_char(str[1])] == vm.Vx[hex_char(str[2])]) {
+        vm.PC += 0x2;
+      }
+      break;
+    case '6':
+      vm.Vx[hex_char(str[1])] = hex_str(str+2);
+      break;
+    case '7':
+      vm.Vx[hex_char(str[1])] += hex_str(str+2);
+      break;
+    case '8':
+      switch(str[3]) {
+        case '0':
+          vm.Vx[hex_char(str[1])] = vm.Vx[hex_char(str[2])];
+          break;
+        case '1':
+          vm.Vx[hex_char(str[1])] |= vm.Vx[hex_char(str[2])];
+          break;
+        case '2':
+          vm.Vx[hex_char(str[1])] &= vm.Vx[hex_char(str[2])];
+          break;
+      }
+  }
+
+  vm.PC += 0x2;
+}
+
+int main(void) {
+  init_vm();
+  load_rom();
+
+#ifdef _WIN32
+  DWORD WINAPI loop(void* data) {
+    while(1) {
+      vm_thread(0);
+      sleep(1);
+    }
+    return 0;
+  }
+  HANDLE thread = CreateThread(NULL, 0, loop, NULL, 0, NULL);
+#else
+  void *loop(void) {
+    while(1) {
+      vm_thread(0);
+      usleep(100);
+    }
+    return 0;
+  } 
+  pthread_t t; pthread_create(&t, NULL, (void*)loop, (void*)0);
+#endif
+
+  init_curses();
+  curses_thread(0);
+
+  return 0;
+}
diff --git a/chip8.h b/chip8.h
new file mode 100644
index 0000000..4ea248f
--- /dev/null
+++ b/chip8.h
@@ -0,0 +1,24 @@
+#pragma once
+
+#include "util.h"
+
+typedef struct {
+  u8* rom;
+  u16 rom_size;
+
+  u16 PC;
+
+  u16 stack[16];
+  u16 stack_pos;
+  u16 stack_count;
+
+  u8 DT;
+  u8 ST;
+  
+  u8 SP;
+  u16 I;
+
+  u8 Vx[16];
+} chip8_vm;
+
+extern chip8_vm vm;
diff --git a/roms/Breakout [Carmelo Cortez, 1979].ch8 b/roms/Breakout [Carmelo Cortez, 1979].ch8
new file mode 100644
index 0000000..70b50db
--- /dev/null
+++ b/roms/Breakout [Carmelo Cortez, 1979].ch8
diff --git a/roms/a.ch8 b/roms/a.ch8
new file mode 100644
index 0000000..f445d49
--- /dev/null
+++ b/roms/a.ch8
diff --git a/roms/e.asm b/roms/e.asm
new file mode 100644
index 0000000..2dd3761
--- /dev/null
+++ b/roms/e.asm
@@ -0,0 +1,22 @@
+CLS
+
+LD V0, 0
+LD V1, 0
+LD V2, 0
+
+loop:
+
+LD   F, V0
+LD   I, esprite
+DRW V1, V2, 5
+ADD V1, 5
+ADD V2, 6
+
+JP loop
+
+esprite:
+db  %11110000,
+    %10000000,
+    %11110000,
+    %10000000,
+    %11110000,
diff --git a/roms/e.ch8 b/roms/e.ch8
new file mode 100644
index 0000000..e890b81
--- /dev/null
+++ b/roms/e.ch8
diff --git a/ui.c b/ui.c
new file mode 100644
index 0000000..d48f3e1
--- /dev/null
+++ b/ui.c
@@ -0,0 +1,35 @@
+#include <ncurses.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "chip8.h"
+
+void init_curses() {
+  initscr();
+  curs_set(0);
+  noecho();
+  nodelay(stdscr, 1);
+  clear();
+}
+
+void curses_thread(void* v) {
+  char c;
+  while(1) {
+    c = getch();
+    if (c == 'q') {
+      endwin();
+      exit(1);
+    }
+    mvaddstr(0, 0, "V0  V1  V2  V3  V4  V5  V6  V7  V8  V9  VA  VB  VC  VD  VE  VF");
+    char buf[5];
+    for (int i = 0; i < 16; i++) {
+      sprintf(buf, "%i", vm.Vx[i]);
+      mvaddstr(1, i * 4, buf);
+    }
+    usleep(100);
+  }
+}
+    
+  
diff --git a/ui.h b/ui.h
new file mode 100644
index 0000000..ea588df
--- /dev/null
+++ b/ui.h
@@ -0,0 +1,4 @@
+#pragma once
+
+void curses_thread(void* v);
+void init_curses();
diff --git a/util.c b/util.c
new file mode 100644
index 0000000..a8c2f94
--- /dev/null
+++ b/util.c
@@ -0,0 +1,14 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "util.h"
+
+u16 hex_str(char* str) {
+  return (u16)strtol(str, NULL, 16);
+}
+
+u16 hex_char(char c) {
+  char buf[2];
+  sprintf(buf, "%c", c);
+  return (u16)strtol(buf, NULL, 16);
+}
diff --git a/util.h b/util.h
new file mode 100644
index 0000000..17760b6
--- /dev/null
+++ b/util.h
@@ -0,0 +1,9 @@
+#include <stdint.h>
+
+#define u8  uint8_t
+#define u16 uint16_t
+#define s8  int8_t
+#define s16 int16_t
+
+u16 hex_char(char c);
+u16 hex_str(char* str);