86Box/src/pit.c

/*IBM AT -
  Write B0
  Write aa55
  Expects aa55 back*/
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <wchar.h>
#include "86box.h"
#include "cpu/cpu.h"
#include "dma.h"
#include "io.h"
#include "nmi.h"
#include "pic.h"
#include "pit.h"
#include "ppi.h"
#include "device.h"
#include "timer.h"
#include "machine/machine.h"
#include "sound/sound.h"
#include "sound/snd_speaker.h"
#include "video/video.h"


/*B0 to 40, two writes to 43, then two reads - value does not change!*/
/*B4 to 40, two writes to 43, then two reads - value _does_ change!*/
int64_t displine;

PIT	pit,
	pit2;
float cpuclock;
float isa_timing, bus_timing;

double	PITCONST;
float	CGACONST;
float	MDACONST;
float	VGACONST1,
	VGACONST2;
float	RTCCONST;

int64_t firsttime=1;
void setpitclock(float clock)
{
        cpuclock=clock;
        PITCONST=clock/(1193181.0 + (2.0 / 3.0));
        CGACONST=(clock/(19687503.0/11.0));
        MDACONST=(clock/2032125.0);
        VGACONST1=(clock/25175000.0);
        VGACONST2=(clock/28322000.0);
        isa_timing = clock/8000000.0;
        bus_timing = clock/(double)cpu_busspeed;
        video_update_timing();
        
        xt_cpu_multi = (int64_t)((14318184.0*(double)(1 << TIMER_SHIFT)) / (double)machines[machine].cpu[cpu_manufacturer].cpus[cpu].rspeed);
        RTCCONST=clock/32768.0;
        TIMER_USEC = (int64_t)((clock / 1000000.0f) * (float)(1 << TIMER_SHIFT));
        device_speed_changed();
}

void pit_reset(PIT *pit)
{
	void (*old_set_out_funcs[3])(int64_t new_out, int64_t old_out);
	PIT_nr old_pit_nr[3];

	memcpy(old_set_out_funcs, pit->set_out_funcs, 3 * sizeof(void *));
	memcpy(old_pit_nr, pit->pit_nr, 3 * sizeof(PIT_nr));
        memset(pit, 0, sizeof(PIT));
	memcpy(pit->set_out_funcs, old_set_out_funcs, 3 * sizeof(void *));
	memcpy(pit->pit_nr, old_pit_nr, 3 * sizeof(PIT_nr));

        pit->l[0] = 0xFFFF; pit->c[0] = 0xFFFFLL*PITCONST;
        pit->l[1] = 0xFFFF; pit->c[1] = 0xFFFFLL*PITCONST;
        pit->l[2] = 0xFFFF; pit->c[2] = 0xFFFFLL*PITCONST;
        pit->m[0] = pit->m[1] = pit->m[2] = 0;
        pit->ctrls[0] = pit->ctrls[1] = pit->ctrls[2] = 0;
        pit->thit[0]=1;
        pit->gate[0] = pit->gate[1] = 1;
        pit->gate[2] = 0;
        pit->using_timer[0] = pit->using_timer[1] = pit->using_timer[2] = 1;
}

void clearpit()
{
        pit.c[0]=(pit.l[0]<<2);
}

float pit_timer0_freq()
{
        if (pit.l[0])
                return (1193181.0 + (2.0 / 3.0))/(float)pit.l[0];
        else
                return (1193181.0 + (2.0 / 3.0))/(float)0x10000;
}

static void pit_set_out(PIT *pit, int64_t t, int64_t out)
{
        pit->set_out_funcs[t](out, pit->out[t]);
        pit->out[t] = out;
}

static void pit_load(PIT *pit, int64_t t)
{
        int64_t l = pit->l[t] ? pit->l[t] : 0x10000LL;
        timer_clock();
        pit->newcount[t] = 0;
        pit->disabled[t] = 0;
        switch (pit->m[t])
        {
                case 0: /*Interrupt on terminal count*/
                pit->count[t] = l;
                pit->c[t] = (int64_t)((l << TIMER_SHIFT) * PITCONST);
                pit_set_out(pit, t, 0);
                pit->thit[t] = 0;
                pit->enabled[t] = pit->gate[t];
                break;
                case 1: /*Hardware retriggerable one-shot*/
                pit->enabled[t] = 1;
                break;
                case 2: /*Rate generator*/
                if (pit->initial[t])
                {
                        pit->count[t] = l - 1;
                        pit->c[t] = (int64_t)(((l - 1) << TIMER_SHIFT) * PITCONST);
                        pit_set_out(pit, t, 1);
                        pit->thit[t] = 0;
                }
                pit->enabled[t] = pit->gate[t];
                break;
                case 3: /*Square wave mode*/
                if (pit->initial[t])
                {
                        pit->count[t] = l;
                        pit->c[t] = (int64_t)((((l + 1) >> 1) << TIMER_SHIFT) * PITCONST);
                        pit_set_out(pit, t, 1);
                        pit->thit[t] = 0;
                }
                pit->enabled[t] = pit->gate[t];
                break;
                case 4: /*Software triggered stobe*/
                if (!pit->thit[t] && !pit->initial[t])
                        pit->newcount[t] = 1;
                else
                {
                        pit->count[t] = l;
                        pit->c[t] = (int64_t)((l << TIMER_SHIFT) * PITCONST);
                        pit_set_out(pit, t, 0);
                        pit->thit[t] = 0;
                }
                pit->enabled[t] = pit->gate[t];
                break;
                case 5: /*Hardware triggered stobe*/
                pit->enabled[t] = 1;
                break;
        }
        pit->initial[t] = 0;
        pit->running[t] = pit->enabled[t] && pit->using_timer[t] && !pit->disabled[t];
        timer_update_outstanding();
}

void pit_set_gate_no_timer(PIT *pit, int64_t t, int64_t gate)
{
        int64_t l = pit->l[t] ? pit->l[t] : 0x10000LL;

        if (pit->disabled[t])
        {
                pit->gate[t] = gate;
                return;
        }
                
        switch (pit->m[t])
        {
                case 0: /*Interrupt on terminal count*/
                case 4: /*Software triggered stobe*/
                pit->enabled[t] = gate;
                break;
                case 1: /*Hardware retriggerable one-shot*/
                case 5: /*Hardware triggered stobe*/
                if (gate && !pit->gate[t])
                {
                        pit->count[t] = l;
                        pit->c[t] = (int64_t)((l << TIMER_SHIFT) * PITCONST);
                        pit_set_out(pit, t, 0);
                        pit->thit[t] = 0;
                        pit->enabled[t] = 1;
                }
                break;
                case 2: /*Rate generator*/
                if (gate && !pit->gate[t])
                {
                        pit->count[t] = l - 1;
                        pit->c[t] = (int64_t)(((l - 1) << TIMER_SHIFT) * PITCONST);
                        pit_set_out(pit, t, 1);
                        pit->thit[t] = 0;
                }                
                pit->enabled[t] = gate;
                break;
                case 3: /*Square wave mode*/
                if (gate && !pit->gate[t])
                {
                        pit->count[t] = l;
                        pit->c[t] = (int64_t)((((l + 1) >> 1) << TIMER_SHIFT) * PITCONST);
                        pit_set_out(pit, t, 1);
                        pit->thit[t] = 0;
                }
                pit->enabled[t] = gate;
                break;
        }
        pit->gate[t] = gate;
        pit->running[t] = pit->enabled[t] && pit->using_timer[t] && !pit->disabled[t];
}

void pit_set_gate(PIT *pit, int64_t t, int64_t gate)
{
        if (pit->disabled[t])
        {
                pit->gate[t] = gate;
                return;
        }
                
        timer_process();

        pit_set_gate_no_timer(pit, t, gate);
        
        timer_update_outstanding();
}

static void pit_over(PIT *pit, int64_t t)
{
        int64_t l = pit->l[t] ? pit->l[t] : 0x10000LL;
        if (pit->disabled[t])
        {
                pit->count[t] += 0xffff;
                pit->c[t] += (int64_t)((0xffff << TIMER_SHIFT) * PITCONST);
                return;
        }
                
        switch (pit->m[t])
        {
                case 0: /*Interrupt on terminal count*/
                case 1: /*Hardware retriggerable one-shot*/
                if (!pit->thit[t])
                        pit_set_out(pit, t, 1);
                pit->thit[t] = 1;
                pit->count[t] += 0xffff;
                pit->c[t] += (int64_t)((0xffff << TIMER_SHIFT) * PITCONST);
                break;
                case 2: /*Rate generator*/
                pit->count[t] += l;
                pit->c[t] += (int64_t)((l << TIMER_SHIFT) * PITCONST);
                pit_set_out(pit, t, 0);
                pit_set_out(pit, t, 1);
                break;
                case 3: /*Square wave mode*/
                if (pit->out[t])
                {
                        pit_set_out(pit, t, 0);
                        pit->count[t] += (l >> 1);
                        pit->c[t] += (int64_t)(((l >> 1) << TIMER_SHIFT) * PITCONST);
                }
                else
                {
                        pit_set_out(pit, t, 1);
                        pit->count[t] += ((l + 1) >> 1);
                        pit->c[t] = (int64_t)((((l + 1) >> 1) << TIMER_SHIFT) * PITCONST);
                }
                break;
                case 4: /*Software triggered strove*/
                if (!pit->thit[t])
                {
                        pit_set_out(pit, t, 0);
                        pit_set_out(pit, t, 1);
                }
                if (pit->newcount[t])
                {
                        pit->newcount[t] = 0;
                        pit->count[t] += l;
                        pit->c[t] += (int64_t)((l << TIMER_SHIFT) * PITCONST);
                }
                else
                {
                        pit->thit[t] = 1;
                        pit->count[t] += 0xffff;
                        pit->c[t] += (int64_t)((0xffff << TIMER_SHIFT) * PITCONST);
                }
                break;
                case 5: /*Hardware triggered strove*/
                if (!pit->thit[t])
                {
                        pit_set_out(pit, t, 0);
                        pit_set_out(pit, t, 1);
                }
                pit->thit[t] = 1;
                pit->count[t] += 0xffff;
                pit->c[t] += (int64_t)((0xffff << TIMER_SHIFT) * PITCONST);
                break;
        }
        pit->running[t] = pit->enabled[t] && pit->using_timer[t] && !pit->disabled[t];
}

int64_t pit_get_timer_0()
{
        int64_t read = (int64_t)((pit.c[0] + ((1 << TIMER_SHIFT) - 1)) / PITCONST) >> TIMER_SHIFT;
        if (pit.m[0] == 2)
                read++;
        if (read < 0LL)
                read = 0LL;
        if (read > 0x10000LL)
                read = 0x10000LL;
        if (pit.m[0] == 3LL)
                read <<= 1LL;
        return read;
}
        
static int64_t pit_read_timer(PIT *pit, int64_t t)
{
        timer_clock();
        if (pit->using_timer[t])
        {
                int64_t read = (int64_t)((pit->c[t] + ((1 << TIMER_SHIFT) - 1)) / PITCONST) >> TIMER_SHIFT;
                if (pit->m[t] == 2)
                        read++;
                if (read < 0LL)
                        read = 0LL;
                if (read > 0x10000LL)
                        read = 0x10000LL;
                if (pit->m[t] == 3LL)
                        read <<= 1LL;
                return read;
        }
        if (pit->m[t] == 2LL)
                return pit->count[t] + 1LL;
        return pit->count[t];
}
        
void pit_write(uint16_t addr, uint8_t val, void *p)
{
        PIT *pit = (PIT *)p;
        int64_t t;
        cycles -= (int64_t)PITCONST;
        
        switch (addr&3)
        {
                case 3: /*CTRL*/
                if ((val&0xC0)==0xC0)
                {
                        if (!(val&0x20))
                        {
                                if (val & 2)
                                        pit->rl[0] = pit_read_timer(pit, 0);
                                if (val & 4)
                                        pit->rl[1] = pit_read_timer(pit, 1);
                                if (val & 8)
                                        pit->rl[2] = pit_read_timer(pit, 2);
                        }
                        if (!(val & 0x10))
                        {
                                if (val & 2)
                                {
                                        pit->read_status[0] = (pit->ctrls[0] & 0x3f) | (pit->out[0] ? 0x80 : 0);
                                        pit->do_read_status[0] = 1;
                                }
                                if (val & 4)
                                {
                                        pit->read_status[1] = (pit->ctrls[1] & 0x3f) | (pit->out[1] ? 0x80 : 0);
                                        pit->do_read_status[1] = 1;
                                }
                                if (val & 8)
                                {
                                        pit->read_status[2] = (pit->ctrls[2] & 0x3f) | (pit->out[2] ? 0x80 : 0);
                                        pit->do_read_status[2] = 1;
                                }
                        }
                        return;
                }
                t = val >> 6;
                pit->ctrl=val;
                if ((val>>7)==3)
                {
                        return;
                }
                if (!(pit->ctrl&0x30))
                {
                        pit->rl[t] = pit_read_timer(pit, t);
                        pit->ctrl |= 0x30;
                        pit->rereadlatch[t] = 0;
                        pit->rm[t] = 3;
                        pit->latched[t] = 1;
                }
                else
                {
                        pit->ctrls[t] = val;
                        pit->rm[t]=pit->wm[t]=(pit->ctrl>>4)&3;
                        pit->m[t]=(val>>1)&7;
                        if (pit->m[t]>5)
                                pit->m[t]&=3;
                        if (!(pit->rm[t]))
                        {
                                pit->rm[t]=3;
                                pit->rl[t] = pit_read_timer(pit, t);
                        }
                        pit->rereadlatch[t]=1;
                        pit->initial[t] = 1;
                        if (!pit->m[t])
                                pit_set_out(pit, t, 0);
                        else
                                pit_set_out(pit, t, 1);
                        pit->disabled[t] = 1;
                }
                pit->wp=0;
                pit->thit[t]=0;
                break;
                case 0: case 1: case 2: /*Timers*/
                t=addr&3;
                switch (pit->wm[t])
                {
                        case 1:
                        pit->l[t]=val;
                        pit_load(pit, t);
                        break;
                        case 2:
                        pit->l[t]=(val<<8);
                        pit_load(pit, t);
                        break;
                        case 0:
                        pit->l[t]&=0xFF;
                        pit->l[t]|=(val<<8);
                        pit_load(pit, t);
                        pit->wm[t]=3;
                        break;
                        case 3:
                        pit->l[t]&=0xFF00;
                        pit->l[t]|=val;
                        pit->wm[t]=0;
                        break;
                }
                speakval=(((float)pit->l[2]/(float)pit->l[0])*0x4000)-0x2000;
                if (speakval>0x2000) speakval=0x2000;
                break;
        }
}

uint8_t pit_read(uint16_t addr, void *p)
{
        PIT *pit = (PIT *)p;
        int64_t t;
        uint8_t temp = 0xff;
        cycles -= (int64_t)PITCONST;        
        switch (addr&3)
        {
                case 0: case 1: case 2: /*Timers*/
                t = addr & 3;
                if (pit->do_read_status[t])
                {
                        pit->do_read_status[t] = 0;
                        temp = pit->read_status[t];
                        break;
                }
                if (pit->rereadlatch[addr & 3] && !pit->latched[addr & 3])
                {
                        pit->rereadlatch[addr & 3] = 0;
                        pit->rl[t] = pit_read_timer(pit, t);
                }
                switch (pit->rm[addr & 3])
                {
                        case 0:
                        temp = pit->rl[addr & 3] >> 8;
                        pit->rm[addr & 3] = 3;
                        pit->latched[addr & 3] = 0;
                        pit->rereadlatch[addr & 3] = 1;
                        break;
                        case 1:
                        temp = (pit->rl[addr & 3]) & 0xFF;
                        pit->latched[addr & 3] = 0;
                        pit->rereadlatch[addr & 3] = 1;
                        break;
                        case 2:
                        temp = (pit->rl[addr & 3]) >> 8;
                        pit->latched[addr & 3] = 0;
                        pit->rereadlatch[addr & 3] = 1;
                        break;
                        case 3:
                        temp = (pit->rl[addr & 3]) & 0xFF;
                        if (pit->m[addr & 3] & 0x80)
                                pit->m[addr & 3] &= 7;
                        else
                                pit->rm[addr & 3] = 0;
                        break;
                }
                break;
                case 3: /*Control*/
                temp = pit->ctrl;
                break;
        }
        return temp;
}

void pit_timer_over(void *p)
{
        PIT_nr *pit_nr = (PIT_nr *)p;
        PIT *pit = pit_nr->pit;
        int64_t timer = pit_nr->nr;

        pit_over(pit, timer);
}

void pit_clock(PIT *pit, int64_t t)
{
        if (pit->thit[t] || !pit->enabled[t])
                return;
        
        if (pit->using_timer[t])
                return;
                
        pit->count[t] -= (pit->m[t] == 3) ? 2 : 1;
        if (!pit->count[t])
                pit_over(pit, t);
}

void pit_set_using_timer(PIT *pit, int64_t t, int64_t using_timer)
{
        timer_process();
        if (pit->using_timer[t] && !using_timer)
                pit->count[t] = pit_read_timer(pit, t);
        if (!pit->using_timer[t] && using_timer)
                pit->c[t] = (int64_t)((pit->count[t] << TIMER_SHIFT) * PITCONST);
        pit->using_timer[t] = using_timer;
        pit->running[t] = pit->enabled[t] && pit->using_timer[t] && !pit->disabled[t];
        timer_update_outstanding();
}

void pit_set_out_func(PIT *pit, int64_t t, void (*func)(int64_t new_out, int64_t old_out))
{
        pit->set_out_funcs[t] = func;
}

void pit_null_timer(int64_t new_out, int64_t old_out)
{
}

void pit_irq0_timer(int64_t new_out, int64_t old_out)
{
        if (new_out && !old_out)
                picint(1);
        if (!new_out)
                picintc(1);
}

void pit_irq0_timer_pcjr(int64_t new_out, int64_t old_out)
{
        if (new_out && !old_out)
        {
                picint(1);
                pit_clock(&pit, 1);
        }
        if (!new_out)
                picintc(1);
}

void pit_irq0_ps2(int64_t new_out, int64_t old_out)
{
        if (new_out && !old_out)
        {
                picint(1);
                pit_set_gate_no_timer(&pit2, 0, 1);
        }
        if (!new_out)
                picintc(1);
        if (!new_out && old_out)
                pit_clock(&pit2, 0);
}

void pit_refresh_timer_xt(int64_t new_out, int64_t old_out)
{
        if (new_out && !old_out)
                dma_channel_read(0);
}

void pit_refresh_timer_at(int64_t new_out, int64_t old_out)
{
        if (new_out && !old_out)
                ppi.pb ^= 0x10;
}

void pit_speaker_timer(int64_t new_out, int64_t old_out)
{
        int64_t l;
        
        speaker_update();
        
        l = pit.l[2] ? pit.l[2] : 0x10000;
        if (l < 25)
                speakon = 0;
        else
                speakon = new_out;
        ppispeakon = new_out;
}


void pit_nmi_ps2(int64_t new_out, int64_t old_out)
{
        nmi = new_out;
        if (nmi)
                nmi_auto_clear = 1;
}

void pit_init()
{
        pit_reset(&pit);

        io_sethandler(0x0040, 0x0004, pit_read, NULL, NULL, pit_write, NULL, NULL, &pit);
        pit.gate[0] = pit.gate[1] = 1;
        pit.gate[2] = 0;
        pit.using_timer[0] = pit.using_timer[1] = pit.using_timer[2] = 1;
        
        pit.pit_nr[0].nr = 0;
        pit.pit_nr[1].nr = 1;
        pit.pit_nr[2].nr = 2;
        pit.pit_nr[0].pit = pit.pit_nr[1].pit = pit.pit_nr[2].pit = &pit;

        timer_add(pit_timer_over, &pit.c[0], &pit.running[0], (void *)&pit.pit_nr[0]);
        timer_add(pit_timer_over, &pit.c[1], &pit.running[1], (void *)&pit.pit_nr[1]);
        timer_add(pit_timer_over, &pit.c[2], &pit.running[2], (void *)&pit.pit_nr[2]);
                
        pit_set_out_func(&pit, 0, pit_irq0_timer);
        pit_set_out_func(&pit, 1, pit_null_timer);
        pit_set_out_func(&pit, 2, pit_speaker_timer);
}

void pit_ps2_init()
{
        pit_reset(&pit2);

        io_sethandler(0x0044, 0x0001, pit_read, NULL, NULL, pit_write, NULL, NULL, &pit2);
        io_sethandler(0x0047, 0x0001, pit_read, NULL, NULL, pit_write, NULL, NULL, &pit2);

        pit2.gate[0] = 0;
        pit2.using_timer[0] = 0;
        pit2.disabled[0] = 1;
                
        pit2.pit_nr[0].nr = 0;
        pit2.pit_nr[0].pit = &pit2;

        timer_add(pit_timer_over, &pit2.c[0], &pit2.running[0], (void *)&pit2.pit_nr[0]);

        pit_set_out_func(&pit, 0, pit_irq0_ps2);
        pit_set_out_func(&pit2, 0, pit_nmi_ps2);
}