mirror of
https://github.com/dschmenk/apple2pi.git
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94 lines
3.2 KiB
C
94 lines
3.2 KiB
C
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/*
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MIT License
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Copyright (c) 2022 Oliver Schmidt (https://a2retro.de/)
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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*/
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#include "bus.pio.h"
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extern const __attribute__((aligned(4))) uint8_t firmware[];
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static bool __not_in_flash( "active") active;
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static uint32_t __not_in_flash("command") command;
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static uint32_t __not_in_flash("control") control;
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void __not_in_flash_func(board)() {
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while (true) {
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uint32_t enbl = pio_sm_get_blocking(pio0, sm_enbl);
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uint32_t addr = enbl & 0x0FFF;
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uint32_t io = enbl & 0x0F00; // IOSTRB or IOSEL
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uint32_t strb = enbl & 0x0800; // IOSTRB
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uint32_t read = enbl & 0x1000; // R/W
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if (addr == 0x0FFF) {
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active = false;
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}
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if (read) {
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if (!io) { // DEVSEL
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switch (addr & 0xF) {
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case 0x8:
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pio_sm_put(pio0, sm_read, sio_hw->fifo_rd);
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break;
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case 0x9:
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// SIO_FIFO_ST_VLD_BITS _u(0x00000001)
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// SIO_FIFO_ST_RDY_BITS _u(0x00000002)
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pio_sm_put(pio0, sm_read, (sio_hw->fifo_st & 3) << 3);
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break;
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case 0xA:
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pio_sm_put(pio0, sm_read, command);
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break;
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case 0xB:
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pio_sm_put(pio0, sm_read, control);
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break;
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}
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} else {
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if (!strb || active) {
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pio_sm_put(pio0, sm_read, firmware[addr]);
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}
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}
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} else {
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uint32_t data = pio_sm_get_blocking(pio0, sm_write);
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if (!io) { // DEVSEL
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switch (addr & 0xF) {
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case 0x8:
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sio_hw->fifo_wr = data;
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break;
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case 0xA:
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command = data;
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break;
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case 0xB:
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control = data;
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break;
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}
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}
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}
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if (io && !strb) {
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active = true;
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}
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gpio_put(gpio_led, active);
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}
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}
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