timings.c

/* timings.c: Timing routines
   Copyright (c) 2003 Philip Kendall
   Copyright (c) 2016 Stuart Brady

   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.,
   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

   Author contact information:

   E-mail: philip-fuse@shadowmagic.org.uk

*/

#include <config.h>

#include <string.h>

#include "internals.h"

typedef struct timings_frame_t {
    // Line timings in tstates
    libspectrum_word left_border, horizontal_screen, right_border, horizontal_retrace;

    // Frame timings in lines
    libspectrum_word top_border, vertical_screen, bottom_border, vertical_retrace;

    // How long does an interrupt last in tstates
    libspectrum_word interrupt_length;

    // How long after interrupt is the top-level pixel of the main screen displayed
    libspectrum_dword top_left_pixel;
} timings_frame_t;

static const timings_frame_t timings_frame_ferranti_5c_6c = {
    24, 128, 24, 48, // Horizontal, 224 clocks per line
    48, 192, 48, 24, // Vertical, 312 lines per frame
    32, 14336
};

static const timings_frame_t timings_frame_ferranti_60hz = {
    24, 128, 24, 48, // Horizontal, 224 clocks per line
    24, 192, 25, 23, // Vertical, 264 lines per frame
    32, 8960
};

static const timings_frame_t timings_frame_ferranti_7c = {
    24, 128, 24, 52, // Horizontal, 228 clocks per line
    48, 192, 48, 23, // Vertical, 311 lines per frame
    36, 14362
};

static const timings_frame_t timings_frame_amstrad_asic = {
    24, 128, 24, 52, // Horizontal, 228 clocks per line
    48, 192, 48, 23, // Vertical, 311 lines per frame
    32, 14365
};

static const timings_frame_t timings_frame_timex_scld_50hz = {
    24, 128, 24, 48, // Horizontal, 224 clocks per line
    48, 192, 48, 24, // Vertical, 312 lines per frame
    32, 14321
};

static const timings_frame_t timings_frame_timex_scld_60hz = {
    24, 128, 24, 48, // Horizontal, 224 clocks per line
    24, 192, 25, 21, // Vertical, 262 lines per frame
    32, 9169
};

static const timings_frame_t timings_frame_se = {
    24, 128, 24, 48, // Horizontal, 224 clocks per line
    47, 192, 48, 25, // Vertical, 312 lines per frame
    32, 14336
};

static const timings_frame_t timings_frame_pentagon = {
    36, 128, 28, 32, // Horizontal, 224 clocks per line
    64, 192, 48, 16, // Vertical 320 lines per frame
    36, 17988
};

static const timings_frame_t timings_frame_scorpion = {
    24, 128, 32, 40, // Horizontal, 224 clocks per line
    48, 192, 48, 24, // Vertical, 312 lines per frame
    36, 14336
};

// The frame timings of a machine
typedef struct timings_t {

    // Processor speed in Hz
    libspectrum_dword processor_speed;

    // AY clock speed in Hz
    libspectrum_dword ay_speed;

    const timings_frame_t *frame_timings;

} timings_t;

// The actual data from which the full timings are constructed
static const timings_t base_timings[] = {

    // 48K
    {3500000, 0, &timings_frame_ferranti_5c_6c},
    // TC2048
    {3500000, 0, &timings_frame_timex_scld_50hz},
    // 128K
    {3546900, 1773400, &timings_frame_ferranti_7c},
    // +2
    {3546900, 1773400, &timings_frame_ferranti_7c},
    // Pentagon
    {3584000, 1792000, &timings_frame_pentagon},
    // +2A
    {3546900, 1773400, &timings_frame_amstrad_asic},
    // +3
    {3546900, 1773400, &timings_frame_amstrad_asic},
    // Unknown machine
    {0, 0, NULL},
    // 16K
    {3500000, 0, &timings_frame_ferranti_5c_6c},
    // TC2068
    {3500000, 1750000, &timings_frame_timex_scld_50hz},
    // Scorpion
    {3500000, 1750000, &timings_frame_scorpion},
    // +3e
    {3546900, 1773400, &timings_frame_amstrad_asic},
    // SE
    {3500000, 1750000, &timings_frame_se},
    // TS2068
    {3528000, 1764000, &timings_frame_timex_scld_60hz},
    // Pentagon 512K
    {3584000, 1792000, &timings_frame_pentagon},
    // Pentagon 1024K
    {3584000, 1792000, &timings_frame_pentagon},
    // 48K NTSC
    {3527500, 0, &timings_frame_ferranti_60hz},
    // 128Ke
    {3546900, 1773400, &timings_frame_amstrad_asic},
};


libspectrum_dword libspectrum_timings_processor_speed(libspectrum_machine machine)
{
    return base_timings[machine].processor_speed;
}


libspectrum_dword libspectrum_timings_ay_speed(libspectrum_machine machine)
{
    return base_timings[machine].ay_speed;
}


libspectrum_word libspectrum_timings_left_border(libspectrum_machine machine)
{
    const timings_frame_t *f = base_timings[machine].frame_timings;
    if (!f) {
        return 0;
    }
    return f->left_border;
}


libspectrum_word libspectrum_timings_horizontal_screen(libspectrum_machine machine)
{
    const timings_frame_t *f = base_timings[machine].frame_timings;
    if (!f) {
        return 0;
    }
    return f->horizontal_screen;
}


libspectrum_word libspectrum_timings_right_border(libspectrum_machine machine)
{
    const timings_frame_t *f = base_timings[machine].frame_timings;
    if (!f) {
        return 0;
    }
    return f->right_border;
}


libspectrum_word libspectrum_timings_horizontal_retrace(libspectrum_machine machine)
{
    const timings_frame_t *f = base_timings[machine].frame_timings;
    if (!f) {
        return 0;
    }
    return f->horizontal_retrace;
}


libspectrum_word libspectrum_timings_top_border(libspectrum_machine machine)
{
    const timings_frame_t *f = base_timings[machine].frame_timings;
    if (!f) {
        return 0;
    }
    return f->top_border;
}


libspectrum_word libspectrum_timings_vertical_screen(libspectrum_machine machine)
{
    const timings_frame_t *f = base_timings[machine].frame_timings;
    if (!f) {
        return 0;
    }
    return f->vertical_screen;
}


libspectrum_word libspectrum_timings_bottom_border(libspectrum_machine machine)
{
    const timings_frame_t *f = base_timings[machine].frame_timings;
    if (!f) {
        return 0;
    }
    return f->bottom_border;
}


libspectrum_word libspectrum_timings_vertical_retrace(libspectrum_machine machine)
{
    const timings_frame_t *f = base_timings[machine].frame_timings;
    if (!f) {
        return 0;
    }
    return f->vertical_retrace;
}


libspectrum_word libspectrum_timings_interrupt_length(libspectrum_machine machine)
{
    const timings_frame_t *f = base_timings[machine].frame_timings;
    if (!f) {
        return 0;
    }
    return f->interrupt_length;
}


libspectrum_word libspectrum_timings_top_left_pixel(libspectrum_machine machine)
{
    const timings_frame_t *f = base_timings[machine].frame_timings;
    if (!f) {
        return 0;
    }
    return f->top_left_pixel;
}


libspectrum_word libspectrum_timings_tstates_per_line(libspectrum_machine machine)
{
    const timings_frame_t *f = base_timings[machine].frame_timings;
    if (!f) {
        return 0;
    }
    return f->left_border + f->horizontal_screen + f->right_border + f->horizontal_retrace;
}


libspectrum_word libspectrum_timings_lines_per_frame(libspectrum_machine machine)
{
    const timings_frame_t *f = base_timings[machine].frame_timings;
    if (!f) {
        return 0;
    }
    return f->top_border + f->vertical_screen + f->bottom_border + f->vertical_retrace;
}


libspectrum_dword libspectrum_timings_tstates_per_frame(libspectrum_machine machine)
{
    const timings_frame_t *f = base_timings[machine].frame_timings;
    if (!f) {
        return 0;
    }
    return libspectrum_timings_tstates_per_line(machine) *
           ((libspectrum_dword)libspectrum_timings_lines_per_frame(machine));
}