From a5d7e68af96d9b62821d8fd47f5039c5bae5d421 Mon Sep 17 00:00:00 2001
From: Reiner Herrmann <reiner@reiner-h.de>
Date: Fri, 10 Feb 2012 14:25:38 +0100
Subject: added original sam_player code

---
 c64/c64.c | 207 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 207 insertions(+)
 create mode 100644 c64/c64.c

(limited to 'c64/c64.c')

diff --git a/c64/c64.c b/c64/c64.c
new file mode 100644
index 0000000..2cbbfe9
--- /dev/null
+++ b/c64/c64.c
@@ -0,0 +1,207 @@
+// c64.c
+//
+// 20060803 Markku Alén
+
+#include "c64.h"
+#include "cpu.h"
+#include "mem.h"
+#include "sid.h"
+#include "cia.h"
+#include "tape.h"
+
+unsigned int total_cycles;
+
+static cia_t cia1;
+
+static int on_chip_port_pins;
+static int on_chip_port_input;
+static int on_chip_port_output;
+static int on_chip_port_direction;
+#define UPDATE_ON_CHIP_PORT_PINS()			(on_chip_port_pins = (on_chip_port_output & on_chip_port_direction) | (on_chip_port_input & ~on_chip_port_direction))
+
+static int page_read(int address)
+{
+	switch(address & 0xffff)
+	{
+	case 0x0000:
+		return on_chip_port_direction;
+	case 0x0001:
+		return on_chip_port_output;
+	default:
+		return ram[address & 0xffff];
+	}
+}
+
+static void page_write(int address, int data)
+{
+	switch(address & 0xffff)
+	{
+	case 0x0000:
+		on_chip_port_direction = data;
+		UPDATE_ON_CHIP_PORT_PINS();
+		break;
+	case 0x0001:
+		on_chip_port_output = data;
+		UPDATE_ON_CHIP_PORT_PINS();
+		break;
+	default:
+		ram[address & 0xffff] = data;
+	}
+}
+
+static int io_read(int address)
+{
+	switch(address & 0x0c00)
+	{
+	case 0x0000:
+		return 0;
+	case 0x0400:
+		return sid_read(address);
+	case 0x0800:
+		return color[address % sizeof(color)];
+	default:
+		switch(address & 0x0300)
+		{
+		case 0x0000:
+			return cia_read(&cia1, address);
+		case 0x0100:
+			return 0;
+		default:
+			return 0x00;
+		}
+	}
+}
+
+static void io_write(int address, int data)
+{
+	switch(address & 0x0c00)
+	{
+	case 0x0000:
+		break;
+	case 0x0400:
+		sid_write(address, data);
+		break;
+	case 0x0800:
+		color[address % sizeof(color)] = data;
+		break;
+	default:
+		switch(address & 0x0300)
+		{
+		case 0x0000:
+			cia_write(&cia1, address, data);
+			if((address & 0x000f) == 0x00)
+				cia_port_b_input(&cia1, kbd_data(cia_a_port_output(&cia1)));
+			break;
+		case 0x0100:
+			break;
+		}
+	}
+}
+
+static int cpu_read(int address)
+{
+	switch(address & 0xf000)
+	{
+	case 0xa000:
+	case 0xb000:
+		switch(on_chip_port_pins & 0x07)
+		{
+		case 0x03:
+		case 0x07:
+			return basic[address % sizeof(basic)];
+		default:
+			return page_read(address);
+		}
+		break;
+	case 0xd000:
+		switch(on_chip_port_pins & 0x07)
+		{
+		case 0x01:
+		case 0x02:
+		case 0x03:
+			return chars[address % sizeof(chars)];
+		case 0x05:
+		case 0x06:
+		case 0x07:
+			return io_read(address);
+		default:
+			return page_read(address);
+		}
+		break;
+	case 0xe000:
+	case 0xf000:
+		switch(on_chip_port_pins & 0x07)
+		{
+		case 0x02:
+		case 0x03:
+		case 0x06:
+		case 0x07:
+			return kernel[address % sizeof(kernel)];
+		default:
+			return page_read(address);
+		}
+		break;
+	default:
+		return page_read(address);
+	}
+}
+
+static void cpu_write(int address, int data)
+{
+	switch(address & 0xf000)
+	{
+	case 0xd000:
+		switch(on_chip_port_pins & 0x07)
+		{
+		case 0x05:
+		case 0x06:
+		case 0x07:
+			io_write(address, data);
+			break;
+		default:
+			page_write(address, data);
+		}
+		break;
+	default:
+		page_write(address, data);
+	}
+}
+
+static void cpu_jam(int address, int op_code)
+{
+	reset_cpu();
+}
+
+void c64_init(void)
+{
+	total_cycles = 0;
+	on_chip_port_input = 0xff;
+	on_chip_port_output = 0x00;
+	on_chip_port_direction = 0x00;
+	UPDATE_ON_CHIP_PORT_PINS();
+	kbd_init();
+	sid_init();
+	cia_init(&cia1);
+	init_cpu(cpu_read, cpu_write, page_read, page_write, cpu_jam);
+	init_tape();
+	reset_cpu();
+}
+
+void c64_run(unsigned int cycle_count)
+{
+	unsigned int elapsed_cycles;
+	for(;;)
+	{
+		elapsed_cycles = cycles;
+		exec_cpu();
+		elapsed_cycles = cycles - elapsed_cycles;
+		if(cycle_count <= elapsed_cycles)
+			break;
+		cycle_count -= elapsed_cycles;
+		total_cycles += elapsed_cycles;
+		cia_exec(&cia1, elapsed_cycles);
+		if(cia1.irq_pin)
+			raise_irq();
+	}
+}
+
-- 
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