Initial Commit

src/io.c

@@ -0,0 +1,14 @@
+#include "io.h"
+
+#include <stdio.h>
+
+int putChar(uint8_t c) {
+  int _c = putchar(c);
+  fflush(stdout);
+  return _c;
+}
+
+int getChar(void) {
+  clearerr(stdin);
+  return getchar();
+}

src/main.c

@@ -0,0 +1,83 @@
+#include "cpu.h"
+#include "ram.h"
+#include "rom.h"
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <termios.h>
+#include <unistd.h>
+
+static struct termios orig_termios;
+
+void restore_terminal(void) { tcsetattr(STDIN_FILENO, TCSANOW, &orig_termios); }
+
+void set_nonblocking_input(void) {
+  struct termios raw;
+
+  tcgetattr(STDIN_FILENO, &orig_termios);
+  atexit(restore_terminal);
+
+  raw = orig_termios;
+  raw.c_lflag &= ~(ICANON | ECHO); // disable line buffering and echo
+  raw.c_cc[VMIN] = 0;              // don't block waiting for input
+  raw.c_cc[VTIME] = 0;
+  tcsetattr(STDIN_FILENO, TCSANOW, &raw);
+
+  // make stdin reads non-blocking too
+  int flags = fcntl(STDIN_FILENO, F_GETFL, 0);
+  fcntl(STDIN_FILENO, F_SETFL, flags | O_NONBLOCK);
+}
+
+int main(void) {
+  uint8_t *ram = NULL;
+  CPU cpu;
+
+  set_nonblocking_input();
+
+  initRom(rom);
+
+  if (createRAM(&ram) != 0) {
+    printf("Could not create RAM\n");
+    return 1;
+  }
+
+  /* DEBUG */
+
+  FILE *fp = fopen("/Users/Kili2/Documents/Projekte/6502pc/6502_65C02_functional_tests/6502_functional_test.bin", "rb");
+  if (!fp) {
+    perror("fopen");
+    return 1;
+  }
+
+  fread(ram, 1, 64 * 1024, fp);
+  if (ferror(fp)) {
+    perror("fread");
+    fclose(fp);
+    return 1;
+  }
+
+  fclose(fp);
+
+  /* DEBUG END*/
+
+  initCPU(&cpu);
+  resetCPU(&cpu, rom);
+
+  while (1) {
+    //printf("\tPC: 0x%x\tOP: 0x%x\n", cpu.ProgrammeCounter, ram[cpu.ProgrammeCounter]);
+    useconds_t sleep = runCycle(&cpu, ram, rom);
+    if (sleep == 1) {
+      printf("opcode missing: 0x%X\n", ram[cpu.ProgrammeCounter - 1]);
+      return 1;
+    }
+    fflush(stdout);
+    usleep(sleep);
+  }
+
+  /* CPU WORK */
+
+  destroyRAM(ram);
+
+  return 0;
+}

src/memoryMap.c

@@ -0,0 +1,44 @@
+#include "memoryMap.h"
+
+uint8_t readMemory(uint16_t address, uint8_t *ram, uint8_t *rom) {
+  if (address < RAM_SIZE || address >= IO_BASE + IO_SIZE) { // FIXME: Expanded for debug
+    return ram[address];
+  } else if (address < RAM_SIZE + IO_SIZE) {
+    uint16_t _address = address - RAM_SIZE;
+    switch (_address) {
+      case KEYBOARD_ADDRESS: {
+        return getChar();
+      }
+
+      default:
+        break;
+    }
+
+    return 0;
+  } else {
+    return rom[address - RAM_SIZE - IO_SIZE];
+  }
+}
+
+void writeMemory(uint16_t address, uint8_t value, uint8_t *ram, uint8_t *rom) {
+  if (address < RAM_SIZE) {
+    ram[address] = value;
+  } else if (address < RAM_SIZE + IO_SIZE || address >= IO_BASE + IO_SIZE) { // FIXME: Expanded for debug
+    uint16_t _address = address - RAM_SIZE;
+    switch (_address) {
+      case SCREEN_ADDRESS: {
+        putChar(value);
+        break;
+      }
+
+      default:
+        break;
+    }
+  } else {
+    rom[address - RAM_SIZE - IO_SIZE] = value;
+  }
+}
+
+uint8_t readStack(uint8_t address, uint8_t *ram) { return ram[0x100 + address]; }
+
+void writeStack(uint8_t address, uint8_t value, uint8_t *ram) { ram[0x100 + address] = value; }

src/ram.c

@@ -0,0 +1,12 @@
+#include "ram.h"
+
+#include <stdlib.h>
+
+int createRAM(uint8_t **ram) {
+  *ram = (uint8_t *)malloc(RAM_SIZE);
+
+  if (*ram == NULL) return -1;
+  return 0;
+}
+
+void destroyRAM(uint8_t *ram) { free(ram); }

src/rom.c

@@ -0,0 +1,17 @@
+#include "rom.h"
+
+uint8_t rom[ROM_SIZE] = {0};
+
+void initRom(uint8_t *rom) {
+  rom[0] = 0xa9,                                             // LDA
+      rom[1] = 'H',                                          // H literal
+      rom[2] = 0x8d,                                         // STA
+      rom[3] = (uint8_t)((IO_BASE + SCREEN_ADDRESS) & 0xFF), // Lower byte of screen
+      rom[4] = (uint8_t)((IO_BASE + SCREEN_ADDRESS) >> 8),   // Upper byte of screen
+      rom[6] = 
+                                                             /* Reset Vector */
+      rom[0xFFFC - ROM_BASE] = 0x00,                         // Lower byte base of ROM
+      rom[0xFFFD - ROM_BASE] = 0x04,                         // Upper byte of base of ROM
+      rom[0xFFFE - ROM_BASE] = 0x00,                         // Lower byte base of ROM
+      rom[0xFFFF - ROM_BASE] = 0x00;                         // Upper byte of base of ROM
+}