344 lines
8.9 KiB
C
344 lines
8.9 KiB
C
/*
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* 86Box A hypervisor and IBM PC system emulator that specializes in
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* running old operating systems and software designed for IBM
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* PC systems and compatibles from 1981 through fairly recent
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* system designs based on the PCI bus.
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*
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* This file is part of the 86Box distribution.
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*
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* Implementation of the ISA Bus (de)Bugger expansion card
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* sold as a DIY kit in the late 1980's in The Netherlands.
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* This card was a assemble-yourself 8bit ISA addon card for
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* PC and AT systems that had several tools to aid in low-
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* level debugging (mostly for faulty BIOSes, bootloaders
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* and system kernels...)
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*
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* The standard version had a total of 16 LEDs (8 RED, plus
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* 8 GREEN), two 7-segment displays and one 8-position DIP
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* switch block on board for use as debugging tools.
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*
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* The "Plus" version, added an extra 2 7-segment displays,
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* as well as a very simple RS-232 serial interface that
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* could be used as a mini-console terminal.
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*
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* Two I/O ports were used; one for control, at offset 0 in
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* I/O space, and one for data, at offset 1 in I/O space.
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* Both registers could be read from and written to. Although
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* the author has a vague memory of a DIP switch to set the
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* board's I/O address, comments in old software seems to
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* indicate that it was actually fixed to 0x7A (and 0x7B.)
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*
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* A READ on the data register always returned the actual
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* state of the DIP switch. Writing data to the LEDs was done
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* in two steps.. first, the block number (RED or GREEN) was
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* written to the CTRL register, and then the actual LED data
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* was written to the DATA register. Likewise, data for the
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* 7-segment displays was written.
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*
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* The serial port was a bit different, and its operation is
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* not verified, but two extra bits in the control register
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* were used to set up parameters, and also the actual data
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* input and output.
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*
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* TODO: Still have to implement the RS232 Serial Port Parameters
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* configuration register (CTRL_SPCFG bit set) but have to
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* remember that stuff first...
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*
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* Version: @(#)bugger.c 1.0.9 2017/10/28
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*
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* Author: Fred N. van Kempen, <decwiz@yahoo.com>
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* Copyright 1989-2017 Fred N. van Kempen.
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*/
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#include <stdio.h>
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#include <stdint.h>
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#include <string.h>
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#include <wchar.h>
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#include "86box.h"
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#include "io.h"
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#include "device.h"
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#include "plat.h"
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#include "ui.h"
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#include "bugger.h"
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/* BugBugger registers. */
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#define BUG_CTRL 0
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# define CTRL_RLED 0x00 /* write to the RED LED block */
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# define CTRL_GLED 0x01 /* write to the GREEN LED block */
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# define CTRL_SEG1 0x02 /* write to the RIGHT 7SEG displays */
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# define CTRL_SEG2 0x04 /* write to the LEFT 7SEG displays */
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# define CTRL_SPORT 0x20 /* enable the serial port */
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# define CTRL_SPCFG 0x40 /* set up the serial port */
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# define CTRL_INIT 0x80 /* enable and reset the card */
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# define CTRL_RESET 0xff /* this resets the board */
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#define BUG_DATA 1
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static uint8_t bug_ctrl, /* control register */
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bug_data, /* data register */
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bug_ledr, bug_ledg, /* RED and GREEN LEDs */
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bug_seg1, bug_seg2, /* LEFT and RIGHT 7SEG displays */
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bug_spcfg; /* serial port configuration */
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# define FIFO_LEN 256
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static uint8_t bug_buff[FIFO_LEN], /* serial port data buffer */
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*bug_bptr;
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# define UISTR_LEN 24
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static char bug_str[UISTR_LEN]; /* UI output string */
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extern void ui_sb_bugui(char *__str);
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/* Update the system's UI with the actual Bugger status. */
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static void
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bug_setui(void)
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{
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/* Format all current info in a string. */
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sprintf(bug_str, "%02X:%02X %c%c%c%c%c%c%c%c-%c%c%c%c%c%c%c%c",
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bug_seg2, bug_seg1,
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(bug_ledg&0x80)?'G':'g', (bug_ledg&0x40)?'G':'g',
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(bug_ledg&0x20)?'G':'g', (bug_ledg&0x10)?'G':'g',
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(bug_ledg&0x08)?'G':'g', (bug_ledg&0x04)?'G':'g',
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(bug_ledg&0x02)?'G':'g', (bug_ledg&0x01)?'G':'g',
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(bug_ledr&0x80)?'R':'r', (bug_ledr&0x40)?'R':'r',
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(bug_ledr&0x20)?'R':'r', (bug_ledr&0x10)?'R':'r',
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(bug_ledr&0x08)?'R':'r', (bug_ledr&0x04)?'R':'r',
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(bug_ledr&0x02)?'R':'r', (bug_ledr&0x01)?'R':'r');
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/* Send formatted string to the UI. */
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ui_sb_bugui(bug_str);
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}
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/* Flush the serial port. */
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static void
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bug_spflsh(void)
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{
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*bug_bptr = '\0';
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pclog("BUGGER- serial port [%s]\n", bug_buff);
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bug_bptr = bug_buff;
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}
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/* Handle a write to the Serial Port Data register. */
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static void
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bug_wsport(uint8_t val)
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{
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uint8_t old = bug_ctrl;
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/* Clear the SPORT bit to indicate we are busy. */
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bug_ctrl &= ~CTRL_SPORT;
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/* Delay while processing byte.. */
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if (bug_bptr == &bug_buff[FIFO_LEN-1]) {
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/* Buffer full, gotta flush. */
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bug_spflsh();
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}
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/* Write (store) the byte. */
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*bug_bptr++ = val;
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/* Restore the SPORT bit. */
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bug_ctrl |= (old & CTRL_SPORT);
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pclog("BUGGER- sport %02x\n", val);
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}
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/* Handle a write to the Serial Port Configuration register. */
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static void
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bug_wspcfg(uint8_t val)
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{
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bug_spcfg = val;
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pclog("BUGGER- spcfg %02x\n", bug_spcfg);
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}
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/* Handle a write to the control register. */
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static void
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bug_wctrl(uint8_t val)
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{
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if (val == CTRL_RESET) {
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/* User wants us to reset. */
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bug_ctrl = CTRL_INIT;
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bug_spcfg = 0x00;
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bug_bptr = NULL;
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} else {
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/* If turning off the serial port, flush it. */
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if ((bug_ctrl & CTRL_SPORT) && !(val & CTRL_SPORT))
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bug_spflsh();
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/* FIXME: did they do this using an XOR of operation bits? --FvK */
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if (val & CTRL_SPCFG) {
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/* User wants to configure the serial port. */
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bug_ctrl &= ~(CTRL_SPORT|CTRL_SEG2|CTRL_SEG1|CTRL_GLED);
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bug_ctrl |= CTRL_SPCFG;
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} else if (val & CTRL_SPORT) {
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/* User wants to talk to the serial port. */
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bug_ctrl &= ~(CTRL_SPCFG|CTRL_SEG2|CTRL_SEG1|CTRL_GLED);
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bug_ctrl |= CTRL_SPORT;
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if (bug_bptr == NULL)
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bug_bptr = bug_buff;
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} else if (val & CTRL_SEG2) {
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/* User selected SEG2 (LEFT, Plus only) for output. */
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bug_ctrl &= ~(CTRL_SPCFG|CTRL_SPORT|CTRL_SEG1|CTRL_GLED);
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bug_ctrl |= CTRL_SEG2;
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} else if (val & CTRL_SEG1) {
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/* User selected SEG1 (RIGHT) for output. */
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bug_ctrl &= ~(CTRL_SPCFG|CTRL_SPORT|CTRL_SEG2|CTRL_GLED);
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bug_ctrl |= CTRL_SEG1;
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} else if (val & CTRL_GLED) {
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/* User selected the GREEN LEDs for output. */
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bug_ctrl &= ~(CTRL_SPCFG|CTRL_SPORT|CTRL_SEG2|CTRL_SEG1);
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bug_ctrl |= CTRL_GLED;
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} else {
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/* User selected the RED LEDs for output. */
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bug_ctrl &=
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~(CTRL_SPCFG|CTRL_SPORT|CTRL_SEG2|CTRL_SEG1|CTRL_GLED);
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}
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}
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/* Update the UI with active settings. */
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pclog("BUGGER- ctrl %02x\n", bug_ctrl);
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bug_setui();
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}
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/* Handle a write to the data register. */
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static void
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bug_wdata(uint8_t val)
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{
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bug_data = val;
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if (bug_ctrl & CTRL_SPCFG)
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bug_wspcfg(val);
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else if (bug_ctrl & CTRL_SPORT)
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bug_wsport(val);
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else {
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if (bug_ctrl & CTRL_SEG2)
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bug_seg2 = val;
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else if (bug_ctrl & CTRL_SEG1)
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bug_seg1 = val;
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else if (bug_ctrl & CTRL_GLED)
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bug_ledg = val;
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else
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bug_ledr = val;
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pclog("BUGGER- data %02x\n", bug_data);
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}
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/* Update the UI with active settings. */
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bug_setui();
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}
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/* Reset the ISA BusBugger controller. */
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static void
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bug_reset(void)
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{
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/* Clear the data register. */
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bug_data = 0x00;
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/* Clear the RED and GREEN LEDs. */
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bug_ledr = 0x00; bug_ledg = 0x00;
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/* Clear both 7SEG displays. */
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bug_seg1 = 0x00; bug_seg2 = 0x00;
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/* Reset the control register (updates UI.) */
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bug_wctrl(CTRL_RESET);
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}
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/* Handle a WRITE operation to one of our registers. */
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static void
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bug_write(uint16_t port, uint8_t val, void *priv)
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{
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switch (port-BUGGER_ADDR) {
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case BUG_CTRL: /* control register */
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if (val == CTRL_RESET) {
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/* Perform a full reset. */
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bug_reset();
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} else if (bug_ctrl & CTRL_INIT) {
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/* Only allow writes if initialized. */
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bug_wctrl(val);
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}
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break;
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case BUG_DATA: /* data register */
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if (bug_ctrl & CTRL_INIT) {
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bug_wdata(val);
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}
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break;
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}
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}
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/* Handle a READ operation from one of our registers. */
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static uint8_t
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bug_read(uint16_t port, void *priv)
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{
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uint8_t ret = 0xff;
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if (bug_ctrl & CTRL_INIT) switch (port-BUGGER_ADDR) {
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case BUG_CTRL: /* control register */
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ret = bug_ctrl;
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break;
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case BUG_DATA: /* data register */
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if (bug_ctrl & CTRL_SPCFG) {
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ret = bug_spcfg;
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} else if (bug_ctrl & CTRL_SPORT) {
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ret = 0x00; /* input not supported */
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} else {
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/* Just read the DIP switch. */
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ret = bug_data;
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}
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break;
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default:
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break;
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}
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return(ret);
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}
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/* Initialize the ISA BusBugger emulator. */
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static void *
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bug_init(device_t *info)
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{
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pclog("%s, I/O=%04x\n", info->name, BUGGER_ADDR);
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/* Initialize local registers. */
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bug_reset();
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io_sethandler(BUGGER_ADDR, BUGGER_ADDRLEN,
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bug_read, NULL, NULL, bug_write, NULL, NULL, NULL);
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/* Just so its not NULL. */
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return(info);
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}
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/* Remove the ISA BusBugger emulator from the system. */
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static void
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bug_close(UNUSED(void *priv))
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{
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io_removehandler(BUGGER_ADDR, BUGGER_ADDRLEN,
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bug_read, NULL, NULL, bug_write, NULL, NULL, NULL);
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}
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device_t bugger_device = {
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"ISA/PCI Bus Bugger",
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DEVICE_ISA | DEVICE_AT,
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0,
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bug_init, bug_close, NULL,
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NULL, NULL, NULL, NULL,
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NULL
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};
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