diff options
Diffstat (limited to 'src/pico1541.c')
| -rw-r--r-- | src/pico1541.c | 195 |
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; +} |