Initial commit

1 files changed, 195 insertions, 0 deletions

diff --git a/src/pico1541.c b/src/pico1541.c
new file mode 100644
index 0000000..5c16e0a
--- /dev/null
+++ b/src/pico1541.c
@@ -0,0 +1,195 @@
+#include <hardware/clocks.h>
+#include <hardware/gpio.h>
+#include <hardware/timer.h>
+
+#include "6502.h"
+#include "6522.h"
+#include "drive.h"
+
+const uint32_t GPIO_CLK = 2;
+const uint32_t GPIO_DATA = 3;
+const uint32_t GPIO_DATA2 = 5;
+const uint32_t GPIO_ATN = 4;
+const uint32_t GPIO_LED = 25;
+
+const uint8_t DEVICE = 8;
+
+static uint8_t ram[2048];
+extern uint8_t _binary__Users_max_Documents_c64_roms_dos1541_start[16384];
+extern uint8_t _binary__Users_max_Downloads_blackbird_1_2_Blackbird_1_2_d64_start[174848];
+// extern uint8_t _binary__Users_max_Downloads_3sira_still_human_by_arise_3sira_by_arise_A_d64_start[174848];
+
+static uint32_t ts;
+static cpu_t cpu;
+static via_t via1;
+static via_t via2;
+static drive_t drive;
+
+int8_t track_step;
+
+void via_pa_read(via_t *via, uint8_t cycle) {
+	if (via == &via2) {
+		via->ira = drive.latched[(drive.current_idx + cycle) & (DRIVE_LOOKAHEAD - 1)];
+	} else {
+		via->ira = via->ora;
+	}
+}
+
+void via_pb_read(via_t *via, uint8_t cycle) {
+	if (via == &via1) {
+		while (ts + cycle > time_us_32()) {}
+		uint8_t clk = gpio_get(GPIO_CLK) ? 0 : 0b00000100;
+		uint8_t data = gpio_get(GPIO_DATA) ? 0 : 0b00000001;
+		uint8_t atn = gpio_get(GPIO_ATN) ? 0 : 0b10000000;
+		uint8_t dev = (DEVICE - 8) << 5;
+		uint8_t atna = via->orb & 0b00010000;
+
+		via->irb = clk | data | atn | dev | atna;
+	} else {
+		uint8_t low = via->orb & 0b00001111;
+		uint8_t sync = drive.sync[(drive.current_idx + cycle) & (DRIVE_LOOKAHEAD - 1)] ? 0 : 0b10000000;
+
+		via->irb = low | sync | 0b00010000;
+	}
+}
+
+void via_pa_write(via_t *via, uint8_t cycle) {
+}
+
+void via_pb_write(via_t *via, uint8_t cycle) {
+	if (via == &via1) {
+		while (ts + cycle > time_us_32()) {}
+		gpio_set_dir(GPIO_CLK, (via->orb & 0b00001000) > 0 && (via->ddrb & 0b00001000) > 0);
+		gpio_set_dir(GPIO_DATA, (via->orb & 0b00000010) > 0 && (via->ddrb & 0b00000010) > 0);
+		if ((via->orb & 0b00010000) && (via->ddrb & 0b00010000)) {
+			gpio_set_dir(GPIO_DATA2, gpio_get(GPIO_ATN));
+		} else {
+			gpio_set_dir(GPIO_DATA2, !gpio_get(GPIO_ATN));
+		}
+	} else if (via == &via2) {
+		if ((via->ddrb & 3) == 3) {
+			int8_t step = via->orb & 3;
+			if (step - track_step > 0) {
+				drive_step_up(&drive);
+			} else if (step - track_step < 0) {
+				drive_step_down(&drive);
+			}
+			track_step = step;
+		}
+
+		drive.spinning = ((via->ddrb & via->orb) & 4) > 0;
+
+		gpio_put(GPIO_LED, (via->orb & 0b00001000) > 0 && (via->ddrb & 0b00001000) > 0);
+	}
+}
+
+uint8_t bus_read(uint16_t addr, uint8_t cycle) {
+	if (addr < 2048) {
+		return ram[addr];
+	} else if (addr >= 0xc000) {
+		return _binary__Users_max_Documents_c64_roms_dos1541_start[addr - 0xc000];
+	} else if (addr >= 0x1800 && addr < 0x1810) {
+		uint8_t v = 0;
+		via_read(&via1, addr - 0x1800, &v, cycle);
+		return v;
+	} else if (addr >= 0x1c00 && addr < 0x1c10) {
+		uint8_t v = 0;
+		via_read(&via2, addr - 0x1c00, &v, cycle);
+		return v;
+	} else {
+		return 0;
+	}
+}
+
+void bus_write(uint16_t addr, uint8_t v, uint8_t cycle) {
+	if (addr < 2048) {
+		ram[addr] = v;
+	} else if (addr >= 0x1800 && addr < 0x1810) {
+		via_write(&via1, addr - 0x1800, v, cycle);
+	} else if (addr >= 0x1c00 && addr < 0x1c10) {
+		via_write(&via2, addr - 0x1c00, v, cycle);
+	}
+}
+
+void atn_irq_callback(uint pin, uint32_t flags) {
+	if (flags & GPIO_IRQ_EDGE_RISE) {
+		if (!(via1.pcr & 1)) {
+			via1.ifr |= 0b10000010;
+		}
+		if ((via1.orb & 0b00010000) && (via1.ddrb & 0b00010000)) {
+			gpio_set_dir(GPIO_DATA2, 1);
+		} else {
+			gpio_set_dir(GPIO_DATA2, 0);
+		}
+	} else {
+		if (via1.pcr & 1) {
+			via1.ifr |= 0b10000010;
+		}
+		if ((via1.orb & 0b00010000) && (via1.ddrb & 0b00010000)) {
+			gpio_set_dir(GPIO_DATA2, 0);
+		} else {
+			gpio_set_dir(GPIO_DATA2, 1);
+		}
+	}
+}
+
+int main() {
+	set_sys_clock_khz(250000, true);
+
+	gpio_init(GPIO_CLK);
+	gpio_init(GPIO_DATA);
+	gpio_init(GPIO_ATN);
+	gpio_init(GPIO_DATA2);
+	gpio_init(25);
+
+	gpio_put(GPIO_CLK, 0);
+	gpio_put(GPIO_DATA, 0);
+	gpio_put(GPIO_LED, 0);
+	gpio_put(GPIO_DATA2, 0);
+
+	gpio_set_dir(GPIO_CLK, GPIO_IN);
+	gpio_set_dir(GPIO_DATA, GPIO_IN);
+	gpio_set_dir(GPIO_ATN, GPIO_IN);
+	gpio_set_dir(GPIO_LED, GPIO_OUT);
+	gpio_set_dir(GPIO_DATA2, GPIO_IN);
+
+	gpio_set_pulls(GPIO_CLK, true, false);
+	gpio_set_pulls(GPIO_DATA, true, false);
+	gpio_set_pulls(GPIO_DATA2, true, false);
+	gpio_set_pulls(GPIO_ATN, true, false);
+
+	gpio_set_irq_enabled_with_callback(GPIO_ATN, GPIO_IRQ_EDGE_RISE | GPIO_IRQ_EDGE_FALL, true, &atn_irq_callback);
+
+	track_step = 0;
+	drive_init(&drive);
+	drive.image = _binary__Users_max_Downloads_blackbird_1_2_Blackbird_1_2_d64_start;
+
+	cpu_reset(&cpu);
+	via_init(&via1);
+	via_init(&via2);
+
+	ts = time_us_32();
+	uint16_t osc2 = 0xffff;
+	while (!cpu.jammed) {
+		if (ts + 100 < time_us_32()) {
+			break;
+		}
+
+		uint8_t cycles = cpu_step(&cpu);
+
+		via_cycle(&via1, cycles);
+		via_cycle(&via2, cycles);
+		cpu.irq = via_irq(&via1) | via_irq(&via2);
+
+		if (drive_cycle(&drive, cycles, true) && (via2.pcr & 0b1110) == 0b1110) {
+			cpu.flags |= 1 << FLAG_V_BIT;
+		}
+
+		ts += cycles;
+		while (ts > time_us_32()) {}
+	}
+
+	gpio_put(GPIO_LED, 1);
+
+	return 0;
+}