Add missing file from new 68K core

1 files changed, 89 insertions, 0 deletions

diff --git a/m68k_util.c b/m68k_util.c
new file mode 100644
index 0000000..d753fdb
--- /dev/null
+++ b/m68k_util.c
@@ -0,0 +1,89 @@
+#include <string.h>
+
+void m68k_read_8(m68k_context *context)
+{
+	context->cycles += 4 * context->opts->gen.clock_divider;
+	context->scratch1 = read_byte(context->scratch1, context->mem_pointers, &context->opts->gen, context);
+}
+
+void m68k_read_16(m68k_context *context)
+{
+	context->cycles += 4 * context->opts->gen.clock_divider;
+	context->scratch1 = read_word(context->scratch1, context->mem_pointers, &context->opts->gen, context);
+}
+
+void m68k_write_8(m68k_context *context)
+{
+	context->cycles += 4 * context->opts->gen.clock_divider;
+	write_byte(context->scratch2, context->scratch1, context->mem_pointers, &context->opts->gen, context);
+}
+
+void m68k_write_16(m68k_context *context)
+{
+	context->cycles += 4 * context->opts->gen.clock_divider;
+	write_word(context->scratch2, context->scratch1, context->mem_pointers, &context->opts->gen, context);
+}
+
+void m68k_sync_cycle(m68k_context *context, uint32_t target_cycle)
+{
+	//TODO: interrupt stuff
+	context->sync_cycle = target_cycle;
+}
+
+void init_m68k_opts(m68k_options *opts, memmap_chunk * memmap, uint32_t num_chunks, uint32_t clock_divider)
+{
+	memset(opts, 0, sizeof(*opts));
+	opts->gen.memmap = memmap;
+	opts->gen.memmap_chunks = num_chunks;
+	opts->gen.address_mask = 0xFFFFFF;
+	opts->gen.byte_swap = 1;
+	opts->gen.max_address = 0x1000000;
+	opts->gen.bus_cycles = 4;
+	opts->gen.clock_divider = clock_divider;
+}
+
+m68k_context *init_68k_context(m68k_options * opts, m68k_reset_handler reset_handler)
+{
+	m68k_context *context = calloc(1, sizeof(m68k_context));
+	context->opts = opts;
+	context->reset_handler = reset_handler;
+	context->int_cycle = 0xFFFFFFFFU;
+	return context;
+}
+
+void m68k_reset(m68k_context *context)
+{
+	//read initial SP
+	context->scratch1 = 0;
+	m68k_read_16(context);
+	context->aregs[7] = context->scratch1 << 16;
+	context->scratch1 = 2;
+	m68k_read_16(context);
+	context->aregs[7] |= context->scratch1;
+	
+	//read initial PC
+	context->scratch1 = 4;
+	m68k_read_16(context);
+	context->pc = context->scratch1 << 16;
+	context->scratch1 = 6;
+	m68k_read_16(context);
+	context->pc |= context->scratch1;
+	
+	context->scratch1 = context->pc;
+	m68k_read_16(context);
+	context->prefetch = context->scratch1;
+	context->pc += 2;
+	
+	context->status = 0x27;
+}
+
+void m68k_print_regs(m68k_context *context)
+{
+	printf("XNZVC\n%d%d%d%d%d\n", context->xflag != 0, context->nflag != 0, context->zflag != 0, context->vflag != 0, context->cflag != 0);
+	for (int i = 0; i < 8; i++) {
+		printf("d%d: %X\n", i, context->dregs[i]);
+	}
+	for (int i = 0; i < 8; i++) {
+		printf("a%d: %X\n", i, context->aregs[i]);
+	}
+}