/*
 * ted-mem.c - Memory interface for the TED emulation.
 *
 * Written by
 *  Andreas Boose <viceteam@t-online.de>
 *  Ettore Perazzoli <ettore@comm2000.it>
 *  Tibor Biczo <crown@axelero.hu>
 *
 * This file is part of VICE, the Versatile Commodore Emulator.
 * See README for copyright notice.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 *  02111-1307  USA.
 *
 */

#include "vice.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "alarm.h"
#include "interrupt.h"
#include "joyport.h"
#include "keyboard.h"
#include "log.h"
#include "maincpu.h"
#include "mem.h"
#include "plus4mem.h"
#include "plus4pio2.h"
#include "raster-changes.h"
#include "ted-badline.h"
#include "ted-fetch.h"
#include "ted-irq.h"
#include "ted-mem.h"
#include "ted-resources.h"
#include "ted-sound.h"
#include "ted-timer.h"
#include "ted.h"
#include "tedtypes.h"
#include "types.h"


/* Unused bits in TED registers: these are always 1 when read.  */
static int unused_bits_in_registers[64] =
{
    0x00 /* $FF00 */, 0x00 /* $FF01 */, 0x00 /* $FF02 */, 0x00 /* $FF03 */,
    0x00 /* $FF04 */, 0x00 /* $FF05 */, 0x00 /* $FF06 */, 0x00 /* $FF07 */,
    0x00 /* $FF08 */, 0x00 /* $FF09 */, 0xa0 /* $FF0A */, 0x00 /* $FF0B */,
    0xfc /* $FF0C */, 0x00 /* $FF0D */, 0x00 /* $FF0E */, 0x00 /* $FF0F */,
    0x00 /* $FF10 */, 0x00 /* $FF11 */, 0x00 /* $FF12 */, 0x00 /* $FF13 */,
    0x00 /* $FF14 */, 0x80 /* $FF15 */, 0x80 /* $FF16 */, 0x80 /* $FF17 */,
    0x80 /* $FF18 */, 0x80 /* $FF19 */, 0x00 /* $FF1A */, 0x00 /* $FF1B */,
    0x00 /* $FF1C */, 0x00 /* $FF1D */, 0x00 /* $FF1E */, 0x00 /* $FF1F */,
    0x00 /* $FF20 */, 0x00 /* $FF21 */, 0x00 /* $FF22 */, 0x00 /* $FF23 */,
    0x00 /* $FF24 */, 0x00 /* $FF25 */, 0x00 /* $FF26 */, 0x00 /* $FF27 */,
    0x00 /* $FF28 */, 0x00 /* $FF29 */, 0x00 /* $FF2A */, 0x00 /* $FF2B */,
    0x00 /* $FF2C */, 0x00 /* $FF2D */, 0x00 /* $FF2E */, 0x00 /* $FF2F */,
    0x00 /* $FF30 */, 0x00 /* $FF31 */, 0x00 /* $FF32 */, 0x00 /* $FF33 */,
    0x00 /* $FF34 */, 0x00 /* $FF35 */, 0x00 /* $FF36 */, 0x00 /* $FF37 */,
    0x00 /* $FF38 */, 0x00 /* $FF39 */, 0x00 /* $FF3A */, 0x00 /* $FF3B */,
    0x00 /* $FF3C */, 0x00 /* $FF3D */, 0xFF /* $FF3E */, 0xFF    /* $FF3F */
};


inline static void ted_local_store_vbank(uint16_t addr, uint8_t value)
{
    unsigned int f;

    ted_delay_clk();

    do {
        CLOCK mclk;

        /* WARNING: Assumes `maincpu_rmw_flag' is 0 or 1.  */
        mclk = maincpu_clk - maincpu_rmw_flag - 1;
        f = 0;

        if (mclk >= ted.draw_clk) {
            ted_raster_draw_alarm_handler(0, NULL);
            f = 1;
        }

        if (mclk >= ted.fetch_clk) {
            /* If the fetch starts here, the sprite fetch routine should
               get the new value, not the old one.  */
            if (mclk == ted.fetch_clk) {
                mem_ram[addr] = value;
            }
            ted_fetch_alarm_handler(maincpu_clk - ted.fetch_clk, NULL);
            f = 1;
            /* WARNING: Assumes `maincpu_rmw_flag' is 0 or 1.  */
            mclk = maincpu_clk - maincpu_rmw_flag - 1;
        }

        ted_delay_clk();
    } while (f);

    mem_ram[addr] = value;
}

inline static void ted_local_store_vbank_32k(uint16_t addr, uint8_t value)
{
    unsigned int f;

    ted_delay_clk();

    do {
        CLOCK mclk;

        /* WARNING: Assumes `maincpu_rmw_flag' is 0 or 1.  */
        mclk = maincpu_clk - maincpu_rmw_flag - 1;
        f = 0;

        if (mclk >= ted.draw_clk) {
            ted_raster_draw_alarm_handler(0, NULL);
            f = 1;
        }

        if (mclk >= ted.fetch_clk) {
            /* If the fetch starts here, the sprite fetch routine should
               get the new value, not the old one.  */
            if (mclk == ted.fetch_clk) {
                mem_ram[addr & 0x7fff] = value;
            }
            ted_fetch_alarm_handler(maincpu_clk - ted.fetch_clk, NULL);
            f = 1;
            /* WARNING: Assumes `maincpu_rmw_flag' is 0 or 1.  */
            mclk = maincpu_clk - maincpu_rmw_flag - 1;
        }

        ted_delay_clk();
    } while (f);

    mem_ram[addr & 0x7fff] = value;
}

inline static void ted_local_store_vbank_16k(uint16_t addr, uint8_t value)
{
    unsigned int f;

    ted_delay_clk();

    do {
        CLOCK mclk;

        /* WARNING: Assumes `maincpu_rmw_flag' is 0 or 1.  */
        mclk = maincpu_clk - maincpu_rmw_flag - 1;
        f = 0;

        if (mclk >= ted.draw_clk) {
            ted_raster_draw_alarm_handler(0, NULL);
            f = 1;
        }

        if (mclk >= ted.fetch_clk) {
            /* If the fetch starts here, the sprite fetch routine should
               get the new value, not the old one.  */
            if (mclk == ted.fetch_clk) {
                mem_ram[addr & 0x3fff] = value;
            }
            ted_fetch_alarm_handler(maincpu_clk - ted.fetch_clk, NULL);
            f = 1;
            /* WARNING: Assumes `maincpu_rmw_flag' is 0 or 1.  */
            mclk = maincpu_clk - maincpu_rmw_flag - 1;
        }

        ted_delay_clk();
    } while (f);

    mem_ram[addr & 0x3fff] = value;
}

/* Encapsulate inlined function for other modules */
void ted_mem_vbank_store(uint16_t addr, uint8_t value)
{
    ted_local_store_vbank(addr, value);
}

void ted_mem_vbank_store_32k(uint16_t addr, uint8_t value)
{
    ted_local_store_vbank_32k(addr, value);
}

void ted_mem_vbank_store_16k(uint16_t addr, uint8_t value)
{
    ted_local_store_vbank_16k(addr, value);
}

#if 0
/* As `store_vbank()', but for the $3900...$39FF address range.  */
void ted_mem_vbank_39xx_store(uint16_t addr, uint8_t value)
{
    ted_local_store_vbank(addr, value);

    if (ted.idle_data_location == IDLE_39FF && (addr & 0x3fff) == 0x39ff) {
        raster_changes_foreground_add_int
            (&ted.raster,
            TED_RASTER_CHAR(TED_RASTER_CYCLE(maincpu_clk)),
            &ted.idle_data,
            value);
    }
}

/* As `store_vbank()', but for the $3F00...$3FFF address range.  */
void ted_mem_vbank_3fxx_store(uint16_t addr, uint8_t value)
{
    ted_local_store_vbank (addr, value);

    if (ted.idle_data_location == IDLE_3FFF && (addr & 0x3fff) == 0x3fff) {
        raster_changes_foreground_add_int
            (&ted.raster,
            TED_RASTER_CHAR(TED_RASTER_CYCLE(maincpu_clk)),
            &ted.idle_data,
            value);
    }
}
#endif

inline static void check_lower_upper_border(const uint8_t value,
                                            unsigned int line, int cycle)
{
    if ((value ^ ted.regs[0x06]) & 8) {
        if (value & 0x8) {
            /* 24 -> 25 row mode switch.  */

            if (line == ted.row_24_stop_line && cycle > 0) {
                /* If on the first line of the 24-line border, we
                   still see the 25-line (lowmost) border because the
                   border flip flop has already been turned on.  */
                ted.raster.blank_enabled = 1;
            } else {
                if (!ted.raster.blank && line == ted.row_24_start_line
                    && cycle > 0) {
                    /* A 24 -> 25 switch somewhere on the first line of
                       the 24-row mode is enough to disable screen
                       blanking.  */
                    ted.raster.blank_enabled = 0;
                }
            }
            TED_DEBUG_REGISTER(("25 line mode enabled"));
        } else {
            /* 25 -> 24 row mode switch.  */

            /* If on the last line of the 25-line border, we still see the
               24-line (upmost) border because the border flip flop has
               already been turned off.  */
            if (!ted.raster.blank && line == ted.row_25_start_line
                && (cycle > 0)) {
                ted.raster.blank_enabled = 0;
            } else {
                if ((line == ted.row_25_stop_line) && (cycle > 0)) {
                    ted.raster.blank_enabled = 1;
                }
            }

            TED_DEBUG_REGISTER(("24 line mode enabled"));
        }
    }
}

inline static void ted06_store(const uint8_t value)
{
    int cycle;
    unsigned int line;
    int old_value;

/*    log_debug(LOG_DEFAULT, "FF06 %03x, %02x",ted.ted_raster_counter, value);*/

    cycle = TED_RASTER_CYCLE(maincpu_clk);
    line = TED_RASTER_Y(maincpu_clk);

    TED_DEBUG_REGISTER(("Control register: $%02X", value));
    TED_DEBUG_REGISTER(("$FF06 tricks at cycle %d, line $%04X, "
                        "value $%02X", cycle, line, value));

    /* This is the funniest part... handle bad line tricks.  */

    if ((line == ted.first_dma_line) && (value & 0x10) != 0) {
        ted.allow_bad_lines = 1;
        ted.raster.ycounter = 0;         /* should be 7 actually */
    }

    if ((ted.raster.ysmooth != (value & 7))
        && (line >= ted.first_dma_line)
        && (line <= ted.last_dma_line)) {
        ted_badline_check_state(value, cycle, line);
    }

    ted.raster.ysmooth = value & 0x7;

    /* Check for 24 <-> 25 line mode switch.  */
    check_lower_upper_border(value, line, cycle);

    ted.raster.blank = !(value & 0x10);        /* `DEN' bit.  */

    old_value = ted.regs[0x06];
    ted.regs[0x06] = value;

    if ((old_value & 0x40) != (value & 0x40)) {
        ted_update_memory_ptrs(cycle);
    }

    /* FIXME: save time.  */
    ted_update_video_mode(cycle);
}

inline static void check_lateral_border(const uint8_t value, int cycle,
                                        raster_t *raster)
{
    if ((value & 0x8) != (ted.regs[0x07] & 0x8)) {
        if (value & 0x8) {
            /* 40 column mode.  */
            if (cycle <= 17) {
                raster->display_xstart = TED_40COL_START_PIXEL;
            } else {
                raster_changes_next_line_add_int(raster,
                                                 &raster->display_xstart,
                                                 TED_40COL_START_PIXEL);
            }
            if (cycle <= 56) {
                raster->display_xstop = TED_40COL_STOP_PIXEL;
            } else {
                raster_changes_next_line_add_int(raster,
                                                 &raster->display_xstop,
                                                 TED_40COL_STOP_PIXEL);
            }
            TED_DEBUG_REGISTER(("40 column mode enabled"));

            /* If CSEL changes from 0 to 1 at cycle 17, the border is
               not turned off and this line is blank.  */
            if ((cycle == 17) && !(ted.regs[0x07] & 0x8)) {
                raster->blank_this_line = 1;
            }
        } else {
            /* 38 column mode.  */
            if (cycle <= 17) {
                raster->display_xstart = TED_38COL_START_PIXEL;
            } else {
                raster_changes_next_line_add_int(raster,
                                                 &raster->display_xstart,
                                                 TED_38COL_START_PIXEL);
            }
            if (cycle <= 56) {
                raster->display_xstop = TED_38COL_STOP_PIXEL;
            } else {
                raster_changes_next_line_add_int(raster,
                                                 &raster->display_xstop,
                                                 TED_38COL_STOP_PIXEL);
            }
            TED_DEBUG_REGISTER(("38 column mode enabled"));

            /* If CSEL changes from 1 to 0 at cycle 56, the lateral
               border is open.  */
            if ((cycle == 56) && (ted.regs[0x07] & 0x8)
                && (!raster->blank_enabled || raster->open_left_border)) {
                raster->open_right_border = 1;
            }
        }
    }
}

inline static void ted07_store(uint8_t value)
{
    raster_t *raster;
    int cycle;
    int old_value;

    TED_DEBUG_REGISTER(("Control register: $%02X", value));

    raster = &ted.raster;
    cycle = TED_RASTER_CYCLE(maincpu_clk);

    /* FIXME: Line-based emulation!  */
    if ((value & 7) != (ted.regs[0x07] & 7)) {
#if 1
        if (TED_RASTER_CHAR(cycle) <= 1) {
            raster->xsmooth = value & 0x7;
        } else {
            raster_changes_next_line_add_int(raster,
                                             &raster->xsmooth,
                                             value & 0x7);
        }
#else
        raster_changes_foreground_add_int(raster,
                                          TED_RASTER_CHAR(cycle),
                                          &raster->xsmooth,
                                          value & 7);
#endif
    }

    /* Bit 4 (CSEL) selects 38/40 column mode.  */
    check_lateral_border(value, cycle, raster);

    ted.reverse_mode = value & 0x80;

    old_value = ted.regs[0x07];

    ted.regs[0x07] = value;

    if ((old_value & 0x90) != (value & 0x90)) {
        ted_update_memory_ptrs(cycle);
    }

    ted_update_video_mode(cycle);
}

inline static void ted08_store(const uint8_t value)
{
    uint8_t val = 0xff;
    uint8_t msk = pio2_kbd;
    uint8_t m;
    uint8_t joy1 = ~read_joyport_dig(JOYPORT_1);
    uint8_t joy2 = ~read_joyport_dig(JOYPORT_2);
    int i;

    for (m = 0x1, i = 0; i < 8; m <<= 1, i++) {
        if (!(msk & m)) {
            val &= ~keyarr[i];
        }
    }

    if (!(value & 4)) {
        val = val & ~(joy1 & 15);
        if (joy1 & 16) {
            val = val & ~64;
        }
    }

    if (!(value & 2)) {
        val = val & ~(joy2 & 15);
        if (joy2 & 16) {
            val = val & ~128;
        }
    }

    ted.kbdval = val;
}

/* IRQ Status

   write bits = 1 to ACK IRQ

   bit 0
   bit 1    raster compare irq
   bit 2
   bit 3    timer 1
   bit 4    timer 2
   bit 5
   bit 6    timer 3
   bit 7    any IRQ triggered
 */
inline static void ted09_store(const uint8_t value)
{
    /* Emulates Read-Modify-Write behaviour. */
    if (maincpu_rmw_flag) {
        ted.irq_status &= ~((ted.last_read & 0x5e) | 0x80);
        if (((maincpu_clk - 1) > (ted.raster_irq_clk)) &&
            (ted.raster_irq_line < ted.screen_height)) {
            ted_irq_next_frame();
        }
    }

    if ((value & 2) && (maincpu_clk > ted.raster_irq_clk)
        && (ted.raster_irq_line < ted.screen_height)) {
        ted_irq_next_frame();
    }

    ted.irq_status &= ~((value & 0x5e) | 0x80);
    ted_irq_set_line();

    TED_DEBUG_REGISTER(("IRQ flag register: $%02X", ted.irq_status));
}

/* IRQ Mask

   bit 0    bit 8 of raster irq compare value
   bit 1    raster compare irq
   bit 2
   bit 3    timer 1
   bit 4    timer 2
   bit 5
   bit 6    timer 3
   bit 7    0: clear mask 1: set mask
 */
inline static void ted0a_store(uint8_t value)
{
    ted.regs[0x0a] = value & 0x5f;

    ted_irq_set_line();

    ted_irq_check_state(value, 1);

    TED_DEBUG_REGISTER(("IRQ mask register: $%02X", ted.regs[0x0a]));
}

/* bit 0-7: bit 0-7 of raster irq compare value */
inline static void ted0b_store(uint8_t value)
{
    TED_DEBUG_REGISTER(("Raster compare register: $%02X", value));

    if (value == ted.regs[0x0b]) {
        return;
    }

    ted.regs[0x0b] = value;

    ted_irq_check_state(value, 0);

    TED_DEBUG_REGISTER(("Raster interrupt line set to $%04X",
                        ted.raster_irq_line));
}

inline static void ted0c0d_store(const uint16_t addr, const uint8_t value)
{
    int pos;

    if (ted.regs[addr] == value) {
        return;
    }

    if (addr & 1) {
        pos = (ted.crsrpos & 0x300) | value;
    } else {
        pos = (ted.crsrpos & 0xff) | ((value & 3) << 8);
    }

#if 0
    raster_changes_background_add_int(&ted.raster,
                                      TED_RASTER_CHAR(TED_RASTER_CYCLE(maincpu_clk)),
                                      &ted.crsrpos,
                                      pos);
#else
    ted.crsrpos = pos;
#endif
    ted.regs[addr] = value;
}

inline static void ted12_store(uint8_t value)
{
    value &= 0x3c;

    if (ted.regs[0x12] == value) {
        return;
    }

    ted.regs[0x12] = value;
    ted_update_memory_ptrs(TED_RASTER_CYCLE(maincpu_clk));
}

inline static void ted13_store(const uint8_t value)
{
    if ((ted.regs[0x13] & 0xfe) == (value & 0xfe)) {
        return;
    }

    if ((ted.regs[0x13] & 2) ^ (value & 2)) {
        if (value & 2) {
            ted.fastmode = 0;
/*            log_debug(LOG_DEFAULT, "Slow mode");*/
        } else {
            ted.fastmode = 1;
/*            log_debug(LOG_DEFAULT, "Fast mode");*/
        }
    }

    ted.regs[0x13] = (ted.regs[0x13] & 0x01) | (value & 0xfe);
    ted_update_memory_ptrs(TED_RASTER_CYCLE(maincpu_clk));
}

inline static void ted14_store(const uint8_t value)
{
    if (ted.regs[0x14] == value) {
        return;
    }

    ted.regs[0x14] = value;
    ted_update_memory_ptrs(TED_RASTER_CYCLE(maincpu_clk));
}

inline static void ted15_store(uint8_t value)
{
    int x_pos;

    value &= 0x7f;

    TED_DEBUG_REGISTER(("Background #0 color register: $%02X", value));

    if (maincpu_rmw_flag) {
        x_pos = TED_RASTER_X(TED_RASTER_CYCLE(first_write_cycle));
        raster_changes_background_add_int(&ted.raster, x_pos,
                                          (int *)&ted.raster.background_color,
                                          0x7f);
        raster_changes_background_add_int(&ted.raster, x_pos + 1,
                                          (int *)&ted.raster.background_color,
                                          ted.regs[0x15]);
    }

    x_pos = TED_RASTER_X(TED_RASTER_CYCLE(last_write_cycle));

    /* FIXME: Check whether this is true on Plus4 */
    if (!ted.force_black_overscan_background_color) {
        raster_changes_background_add_int
            (&ted.raster, x_pos,
            &ted.raster.idle_background_color, value);
        raster_changes_background_add_int
            (&ted.raster, x_pos,
            &ted.raster.xsmooth_color, value);
    }

    raster_changes_background_add_int(&ted.raster, x_pos,
                                      (int *)&ted.raster.background_color,
                                      0x7f);
    raster_changes_background_add_int(&ted.raster, x_pos + 1,
                                      (int *)&ted.raster.background_color,
                                      value);
    ted.regs[0x15] = value;
}

inline static void ted161718_store(uint16_t addr, uint8_t value)
{
    int char_num;

    value &= 0x7f;

    TED_DEBUG_REGISTER(("Background color #%d register: $%02X",
                        addr - 0x15, value));

    ted.regs[addr] = value;

    /* FIXME add sparkle effect */
    char_num = TED_RASTER_CHAR(TED_RASTER_CYCLE(last_write_cycle));

    raster_changes_foreground_add_int(&ted.raster,
                                      char_num,
                                      &ted.ext_background_color[addr - 0x16],
                                      value);
}

inline static void ted19_store(uint8_t value)
{
    int x_pos;

    TED_DEBUG_REGISTER(("Border color register: $%02X", value));

    value &= 0x7f;

    if (maincpu_rmw_flag) {
        x_pos = TED_RASTER_X(TED_RASTER_CYCLE(first_write_cycle));
        raster_changes_border_add_int(&ted.raster,
                                      x_pos,
                                      (int *)&ted.raster.border_color,
                                      0x7f);
        raster_changes_border_add_int(&ted.raster,
                                      x_pos + 1,
                                      (int *)&ted.raster.border_color,
                                      ted.regs[0x19]);
    }

    ted.regs[0x19] = value;

    x_pos = TED_RASTER_X(TED_RASTER_CYCLE(last_write_cycle));

    raster_changes_border_add_int(&ted.raster,
                                  x_pos,
                                  (int *)&ted.raster.border_color,
                                  0x7f);
    raster_changes_border_add_int(&ted.raster,
                                  x_pos + 1,
                                  (int *)&ted.raster.border_color,
                                  value);
}

inline static void ted1a1b_store(uint16_t addr, uint8_t value)
{
    unsigned int new_counter;

    ted.regs[addr] = value;
    if (addr == 0x1a) {
        new_counter = ((value & 1) << 8) + (ted.mem_counter & 0xff);
    } else {
        new_counter = (ted.mem_counter & 0x100) | value;
    }
    ted.mem_counter = new_counter;
}

inline static void ted1c1d_store(uint16_t addr, uint8_t value)
{
    unsigned int new_raster;
    int diff;

    ted.regs[addr] = value;
    if (addr == 0x1c) {
        new_raster = ((value & 1) << 8) + (ted.ted_raster_counter & 0xff);
    } else {
        new_raster = (ted.ted_raster_counter & 0x100) + value;
    }

/*    log_debug(LOG_DEFAULT, "Raster change old %03x, new %03x",ted.ted_raster_counter, new_raster);*/
    if ((new_raster >= ted.first_dma_line) &&
        (new_raster <= ted.last_dma_line)) {
        ted.fetch_clk = ted.last_emulate_line_clk + TED_FETCH_CYCLE + ted.cycles_per_line;
        alarm_set(ted.raster_fetch_alarm, ted.fetch_clk);
    } else {
        if (new_raster >= ted.screen_height) {
            diff = 512 - new_raster;
        } else {
            diff = ted.screen_height - new_raster;
        }
        ted.fetch_clk = ted.last_emulate_line_clk + TED_FETCH_CYCLE + diff * ted.cycles_per_line;

        alarm_set(ted.raster_fetch_alarm, ted.fetch_clk);
    }

    if (ted.raster_irq_line < ted.screen_height) {
        /* int casts are to ensure that subtraction can become negative */
        ted.raster_irq_clk = (TED_LINE_START_CLK(maincpu_clk)
                              + TED_RASTER_IRQ_DELAY - INTERRUPT_DELAY
                              + (ted.cycles_per_line
                                 * ((int)ted.raster_irq_line - (int)new_raster)));

        /* Raster interrupts on line 0 are delayed by 1 cycle.  */
        /* FIXME this needs to be checked */
        /*if (ted.raster_irq_line == 0)
            ted.raster_irq_clk++;*/

        if (ted.raster_irq_line <= new_raster) {
            ted.raster_irq_clk += ((new_raster >= ted.screen_height ? 512 : ted.screen_height)
                                   * ted.cycles_per_line);
        }
        alarm_set(ted.raster_irq_alarm, ted.raster_irq_clk);
    } else {
        if (new_raster >= ted.screen_height) {
            /* int casts are to ensure that subtraction can become negative */
            ted.raster_irq_clk = (TED_LINE_START_CLK(maincpu_clk)
                                  + TED_RASTER_IRQ_DELAY - INTERRUPT_DELAY
                                  + (ted.cycles_per_line
                                     * ((int)ted.raster_irq_line - (int)new_raster)));

            if (ted.raster_irq_line <= new_raster) {
                ted.raster_irq_clk = CLOCK_MAX;
                alarm_unset(ted.raster_irq_alarm);
            } else {
                alarm_set(ted.raster_irq_alarm, ted.raster_irq_clk);
            }
        } else {
            ted.raster_irq_clk = CLOCK_MAX;
            alarm_unset(ted.raster_irq_alarm);
        }
    }

    ted.ted_raster_counter = new_raster;
}

inline static void ted1e_store(uint8_t value)
{
    /* FIXME */
    /* int new_hcount = (~value & 0xfc) >> 1; */
}

inline static void ted1f_store(uint8_t value)
{
    int current_cursor_phase;
    int new_cursor_count;

    new_cursor_count = (value >> 3) & 0x0f;
    current_cursor_phase = ted.cursor_phase & 0x10;

    if ((ted.cursor_phase & 0x0f) == 0x0f && (new_cursor_count & 0x0f) != 0x0f) {
        current_cursor_phase ^= 0x10;
    }
    ted.cursor_phase = current_cursor_phase | new_cursor_count;
    ted.cursor_visible = ted.cursor_phase & 0x10;
    ted.raster.ycounter = value & 7;
}

inline static void ted3e_store(void)
{
    ted.regs[0x13] |= 0x01;
    mem_config_ram_set(1);
    ted_update_memory_ptrs(TED_RASTER_CYCLE(maincpu_clk));
}

inline static void ted3f_store(void)
{
    ted.regs[0x13] &= 0xfe;
    mem_config_ram_set(0);
    ted_update_memory_ptrs(TED_RASTER_CYCLE(maincpu_clk));
}

/* Store a value in a TED register.  */
void ted_store(uint16_t addr, uint8_t value)
{
    addr &= 0x3f;

    /* WARNING: assumes `maincpu_rmw_flag' is 0 or 1.  */
    ted_handle_pending_alarms(maincpu_rmw_flag + 1);

    /* This is necessary as we must be sure that the previous line has been
       updated and `current_line' is actually set to the current Y position of
       the raster.  Otherwise we might mix the changes for this line with the
       changes for the previous one.  */
    if (maincpu_clk >= ted.draw_clk) {
        ted_raster_draw_alarm_handler(maincpu_clk - ted.draw_clk, NULL);
    }

    switch (addr) {
        case 0x00:
        case 0x01:
        case 0x02:
        case 0x03:
        case 0x04:
        case 0x05:
            ted_timer_store(addr, value);
            break;
        case 0x06:
            ted06_store(value);
            break;
        case 0x07:
            ted07_store(value);
            break;
        case 0x08:
            ted08_store(value);
            break;
        case 0x09:
            ted09_store(value);
            break;
        case 0x0a:
            ted0a_store(value);
            break;
        case 0x0b:
            ted0b_store(value);
            break;
        case 0x0c:
        case 0x0d:
            ted0c0d_store(addr, value);
            break;
        case 0x0e:
        case 0x0f:
        case 0x10:
        case 0x11:
            ted_sound_store(addr, value);
            break;
        case 0x12:
            ted12_store(value);
            ted_sound_store(addr, value);
            break;
        case 0x13:
            ted13_store(value);
            break;
        case 0x14:
            ted14_store(value);
            break;
        case 0x15:
            ted15_store(value);
            break;
        case 0x16:
        case 0x17:
        case 0x18:
            ted161718_store(addr, value);
            break;
        case 0x19:
            ted19_store(value);
            break;
        case 0x1a:
        case 0x1b:
            ted1a1b_store(addr, value);
            break;
        case 0x1c:
        case 0x1d:
            ted1c1d_store(addr, value);
            break;
        case 0x1e:
            ted1e_store(value);
            break;
        case 0x1f:
            ted1f_store(value);
            break;
        case 0x3e:
            ted3e_store();
            break;
        case 0x3f:
            ted3f_store();
            break;
    }
}

/* FIXME: unused? */
#if 0
inline static unsigned int read_raster_y(void)
{
    int raster_y;

    raster_y = TED_RASTER_Y(maincpu_clk);

    /* Line 0 is 62 cycles long, while line (SCREEN_HEIGHT - 1) is 64
       cycles long.  As a result, the counter is incremented one
       cycle later on line 0.  */
    if (raster_y == 0 && TED_RASTER_CYCLE(maincpu_clk) == 0) {
        raster_y = ted.screen_height - 1;
    }

    return raster_y;
}
#endif

inline static uint8_t ted08_read(void)
{
    return ted.kbdval;
}

/* IRQ Status

   bit 0
   bit 1    raster compare irq
   bit 2
   bit 3    timer 1
   bit 4    timer 2
   bit 5
   bit 6    timer 3
   bit 7    any IRQ triggered
 */
inline static uint8_t ted09_read(void)
{
    /* Manually set raster IRQ flag if the opcode reading $09 has crossed
       the line end and the raster IRQ alarm has not been executed yet. */
    if (TED_RASTER_Y(maincpu_clk) == ted.raster_irq_line
        && ted.raster_irq_clk != CLOCK_MAX
        && maincpu_clk >= ted.raster_irq_clk) {
        if (ted.regs[0x0a] & 0x2) {
            ted.last_read = ted.irq_status | 0xa7;
        } else {
            ted.last_read = ted.irq_status | 0x27;
        }
    } else {
        ted.last_read = ted.irq_status | 0x25;
    }

    return ted.last_read;
}

/* IRQ Mask

   bit 0
   bit 1    raster compare irq
   bit 2
   bit 3    timer 1
   bit 4    timer 2
   bit 5
   bit 6    timer 3
   bit 7
 */
inline static uint8_t ted0a_read(void)
{
    return (ted.regs[0x0a] & 0x5f) | 0xa0;
}

inline static uint8_t ted12_read(void)
{
    return ted.regs[0x12] | 0xc0;
}

inline static uint8_t ted1a1b_read(uint16_t addr)
{
    if (addr == 0x1a) {
        return ((ted.mem_counter & 0x100) >> 8) | 0xfc;
    } else {
        return ted.mem_counter & 0xff;
    }
}

inline static uint8_t ted1c1d_read(uint16_t addr)
{
    unsigned int tmp = TED_RASTER_Y(maincpu_clk);

    if (addr == 0x1c) {
        return (((tmp & 0x100) >> 8) | 0xfe) & 0xff;
    } else {
        return tmp & 0xff;
    }
}

inline static uint8_t ted1e_read(void)
{
    int xpos;

    xpos = ((int)TED_RASTER_CYCLE(maincpu_clk) - 16) * 4;
    if (xpos < 0) {
        xpos = ted.cycles_per_line * 4 + xpos;
    }

    xpos = (xpos / 2) & 0xfe;


    return (uint8_t)xpos;
}

inline static uint8_t ted1f_read(void)
{
    return 0x80 | ((ted.cursor_phase & 0x0f) << 3) | ted.raster.ycounter;
}

/* Read a value from a TED register.  */
uint8_t ted_read(uint16_t addr)
{
    addr &= 0x3f;

    /* Serve all pending events.  */
    ted_handle_pending_alarms(0);

    switch (addr) {
        case 0x00:
        case 0x01:
        case 0x02:
        case 0x03:
        case 0x04:
        case 0x05:
            return ted_timer_read(addr);
        case 0x08:
            return ted08_read();
        case 0x09:
            return ted09_read();
        case 0x0a:
            return ted0a_read();
        case 0x0e:
        case 0x0f:
        case 0x10:
        case 0x11:
            return ted_sound_read(addr);
        case 0x12:
            return ted_sound_read(addr) | ted12_read();
        case 0x1a:
        case 0x1b:
            return ted1a1b_read(addr);
        case 0x1c:
        case 0x1d:
            return ted1c1d_read(addr);
        case 0x1e:
            return ted1e_read();
        case 0x1f:
            return ted1f_read();
    }

    return ted.regs[addr] | unused_bits_in_registers[addr];
}

inline static uint8_t ted09_peek(void)
{
    /* Manually set raster IRQ flag if the opcode reading $19 has crossed
       the line end and the raster IRQ alarm has not been executed yet. */
    if (TED_RASTER_Y(maincpu_clk) == ted.raster_irq_line
        && ted.raster_irq_clk != CLOCK_MAX
        && maincpu_clk >= ted.raster_irq_clk) {
        if (ted.regs[0x0a] & 0x2) {
            return ted.irq_status | 0xa3;
        } else {
            return ted.irq_status | 0x23;
        }
    } else {
        return ted.irq_status | 0x21;
    }

    return ted.irq_status;
}

uint8_t ted_peek(uint16_t addr)
{
    addr &= 0x3f;

    switch (addr) {
        case 0x00:
        case 0x01:
        case 0x02:
        case 0x03:
        case 0x04:
        case 0x05:
            return ted_timer_read(addr);
        case 0x08:
            return ted08_read();
        case 0x09:
            return ted09_peek();
        case 0x0e:
        case 0x0f:
        case 0x10:
        case 0x11:
            return ted_sound_read(addr);
        case 0x12:
            return ted_sound_read(addr) | ted12_read();
        case 0x1a:
        case 0x1b:
            return ted1a1b_read(addr);
        case 0x1c:
        case 0x1d:
            return ted1c1d_read(addr);
        case 0x1e:
            return ted1e_read();
        case 0x1f:
            return ted1f_read();
        default:
            return ted.regs[addr] | unused_bits_in_registers[addr];
    }
}