1 files changed, 102 insertions, 0 deletions
diff --git a/emulator.cpp b/emulator.cpp
new file mode 100644
index 0000000..0e3fb29
--- /dev/null
+++ b/emulator.cpp
@@ -0,0 +1,102 @@
+/* SPDX-License-Identifier: Unlicense
+ */
+
+#include "bus.hpp"
+#include "musashi-m68k/m68k.h"
+
+#include <cstdio>
+#include <cstdlib>
+#include <cstdarg>
+#include <ctime>
+
+#if !defined(DEBUG_TRACE_INSTRUCTIONS)
+#   define DEBUG_TRACE_INSTRUCTIONS 0
+#endif
+
+static void exit_error(const char* fmt, ...)
+{
+    va_list args;
+    va_start(args, fmt);
+    vfprintf(stderr, fmt, args);
+    va_end(args);
+    fprintf(stderr, "\n");
+    exit(EXIT_FAILURE);
+}
+
+/* Called when the CPU pulses the RESET line */
+void m68k_reset_callback(void)
+{
+    // TODO
+}
+
+/* Called when the CPU acknowledges an interrupt */
+int m68k_irq_ack(int level)
+{
+    (void) level;
+    // TODO
+    exit_error("IRQ ack");
+    return M68K_INT_ACK_SPURIOUS;
+}
+
+static void make_hex(char* buff, unsigned int pc, unsigned int length)
+{
+    char* ptr = buff;
+
+    for (;length>0;length -= 2)
+    {
+        sprintf(ptr, "%04x", m68k_read_disassembler_16(pc));
+        pc += 2;
+        ptr += 4;
+        if (length > 2)
+            *ptr++ = ' ';
+    }
+}
+
+void m68k_instr_callback(int pc)
+{
+    if (!DEBUG_TRACE_INSTRUCTIONS)
+        return;
+    char buff[100];
+    unsigned int instr_size =
+        m68k_disassemble(buff, pc, M68K_CPU_TYPE_68000);
+    char buff2[100];
+    make_hex(buff2, pc, instr_size);
+    printf("E %08X: %-20s: %s\n", pc, buff2, buff);
+    fflush(stdout);
+}
+
+int main(int argc, char* argv[])
+{
+    if (argc != 2)
+    {
+        printf("Usage: sim <program file>\n");
+        exit(-1);
+    }
+
+    FILE* const fhandle = fopen(argv[1], "rb");
+
+    if (fhandle == NULL)
+        exit_error("Unable to open %s", argv[1]);
+
+    const size_t fread_ret = fread(g_rom, 1, ROM_SIZE, fhandle);
+    if (fread_ret <= 0)
+        exit_error("Error reading %s", argv[1]);
+    printf("Read into ROM %zu bytes\n", fread_ret);
+
+    m68k_init();
+    m68k_set_cpu_type(M68K_CPU_TYPE_68000);
+    m68k_pulse_reset();
+
+    while (1)
+    {
+        // Values to execute determine the interleave rate.
+        // Smaller values allow for more accurate interleaving with multiple
+        // devices/CPUs but is more processor intensive.
+        // 100000 is usually a good value to start at, then work from there.
+
+        // Note that I am not emulating the correct clock speed!
+        m68k_execute(100000);
+    }
+
+    return 0;
+}