uint32_t serial_cx_read(uint32_t addr) {
switch (addr & 0xFFFF) {
case 0x000:
if (!(serial_cx.rx & 1))
error("Attempted to read empty RBR");
uint8_t byte = serial_cx.rx_char;
serial_cx.rx = 0;
serial_cx.int_status &= ~0x10;
serial_cx_int_check();
xmodem_next_char();
return byte;
case 0x018: return 0x90 & ~(serial_cx.rx << 4);
case 0x024: return 0;
case 0x028: return 0;
case 0x02C: return 0;
case 0x040: return serial_cx.int_status & serial_cx.int_mask;
case 0x030: return serial_cx.cr;
case 0x038: return 0;
case 0xFE0: return 0x11;
case 0xFE4: return 0x10;
case 0xFE8: return 0x14;
case 0xFEC: return 0x00;
case 0xFF0: return 0x0d;
case 0xFF4: return 0xf0;
case 0xFF8: return 0x05;
case 0xFFC: return 0xb1;
}
return bad_read_word(addr);
}
uint32_t serial_read(uint32_t addr) {
switch (addr & 0x3F) {
case 0x00:
if (serial.LCR & 0x80)
return serial.DLL; /* Divisor Latch LSB */
if (!(serial.interrupts & 1))
error("Attempted to read empty RBR");
uint8_t byte = serial.rx_char;
serial.interrupts &= ~1;
serial_int_check();
xmodem_next_char();
return byte;
case 0x04:
if (serial.LCR & 0x80)
return serial.DLM; /* Divisor Latch MSB */
return serial.IER; /* Interrupt Enable Register */
case 0x08: /* Interrupt Identification Register */
if (serial.interrupts & serial.IER & 1) {
return 4;
} else if (serial.interrupts & serial.IER & 2) {
serial.interrupts &= ~2;
serial_int_check();
return 2;
} else {
return 1;
}
case 0x0C: /* Line Control Register */
return serial.LCR;
case 0x14: /* Line Status Register */
return 0x60 | (serial.interrupts & 1);
}
return bad_read_word(addr);
}
static void xmodem_next_packet() {
int len;
int i, sum = 0;
xmodem_buf[0] = 0x01;
xmodem_buf[1]++; // sequence number
xmodem_buf[2] = ~xmodem_buf[1]; // sequence number complement
len = fread(&xmodem_buf[3], 1, 0x80, xmodem_file);
if (len == 0) {
serial_byte_in(0x04);
fclose(xmodem_file);
xmodem_file = NULL;
return;
}
memset(&xmodem_buf[3 + len], 0x1A, 0x80 - len);
for (i = 3; i < 0x83; i++) sum += xmodem_buf[i];
xmodem_buf[0x83] = sum;
xmodem_buf_pos = 0;
xmodem_next_char();
}
