Subversion Repositories s80186

// Copyright Jamie Iles, 2017

//

// This file is part of s80x86.

//

// s80x86 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 3 of the License, or

// (at your option) any later version.

//

// s80x86 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 s80x86.  If not, see <http://www.gnu.org/licenses/>.

#include "bda.h"

#include "bios.h"

#include "display.h"

#include "sd.h"

#include "io.h"

#include "serial.h"

#include "keyboard.h"

#include "timer.h"

#include "utils.h"

#define INT11_DISKS_PRESENT (1 << 0)

#define INT11_CGA_ADAPTOR (2 << 4)

static void equipment_check(struct callregs *regs)

{

    regs->ax.x = INT11_CGA_ADAPTOR;

}

VECTOR(0x11, equipment_check);

static void serial_services(struct callregs *regs)

{

    regs->flags |= CF;

}

VECTOR(0x14, serial_services);

static void system_services(struct callregs *regs)

{

    regs->flags |= CF;

    regs->ax.h = 0x86;

}

VECTOR(0x15, system_services);

// Printer services

static void printer_services(struct callregs *regs)

{

    regs->flags |= CF;

}

VECTOR(0x17, printer_services);

static void basic_services(struct callregs __unused *regs)

{

    panic("No basic services\n");

}

VECTOR(0x18, basic_services);

static void boostrap_loader(struct callregs __unused *regs)

{

    asm volatile("jmp $0xffff, $0x0");

}

VECTOR(0x19, boostrap_loader);

static void conventional_memory(struct callregs *regs)

{

    regs->ax.x = 640;

}

VECTOR(0x12, conventional_memory);

static void break_handler(struct callregs __unused *regs)

{

    panic("No break handler\n");

}

VECTOR(0x1b, break_handler);

static void set_vector(int vector, void *handler)

{

    writew(0, vector * 4, (unsigned short)handler);

    writew(0, vector * 4 + 2, get_cs());

}

static unsigned char vpt[] = {80, 25, 8, 4000 & 0xff, 4000 >> 8};

static void install_vectors(void)

{

    struct vector {

        unsigned short num;

        void *handler;

    };

    extern struct vector vectors_start;

    extern struct vector vectors_end;

    struct vector *v;

    for (v = &vectors_start; v < &vectors_end; ++v)

        set_vector(v->num, v->handler);

    set_vector(0x1d, vpt);

}

static void bda_init(void)

{

    int i;

    for (i = 0; i < 256; ++i)

        writeb(0x40, i, 0);

}

#define PIC_COMMAND 0x20

#define PIC_DATA 0x21

#define PIC_ICW1_INIT (1 << 4)

#define PIC_ICW1_SINGLE (1 << 1)

#define PIC_ICW1_ICW4 (1 << 0)

#define PIC_ICW4_8086 (1 << 0)

static void irq_init(void)

{

    outb(PIC_COMMAND, PIC_ICW1_INIT | PIC_ICW1_SINGLE | PIC_ICW1_ICW4);

    outb(PIC_DATA, 0x08);

    outb(PIC_DATA, PIC_ICW4_8086);

    // All IRQs initially masked.

    outb(PIC_DATA, ~0);

}

void irq_enable(int irq_num)

{

    outb(PIC_DATA, inb(PIC_DATA) & ~(1 << irq_num));

}

void irq_ack(void)

{

    outb(0x20, 0x20);

}

void root(void)

{

    install_vectors();

    irq_init();

    bda_init();

    display_init();

    putstr("s80x86 BIOS, (C) Jamie Iles, " __DATE__ " " __TIME__ "\n");

    putstr("Platform: " __PLATFORM__ "\n");

    putstr("Build: " __BUILD__ "\n");

    putstr("\n");

    keyboard_init();

    init_timer();

    sd_init();

    sd_boot();

}