sb16.c

qemu虚拟机代码

            retval = s->out_data[--s->out_data_len];
            s->last_read_byte = retval;
        }
        else {
            if (s->cmd != -1) {
                dolog ("empty output buffer for command %#x\n",
                       s->cmd);
            }
            retval = s->last_read_byte;
            /* goto error; */
        }
        break;

    case 0x0c:                  /* 0 can write */
        retval = s->can_write ? 0 : 0x80;
        break;

    case 0x0d:                  /* timer interrupt clear */
        /* dolog ("timer interrupt clear\n"); */
        retval = 0;
        break;

    case 0x0e:                  /* data available status | irq 8 ack */
        retval = (!s->out_data_len || s->highspeed) ? 0 : 0x80;
        if (s->mixer_regs[0x82] & 1) {
            ack = 1;
            s->mixer_regs[0x82] &= 1;
            pic_set_irq (s->irq, 0);
        }
        break;

    case 0x0f:                  /* irq 16 ack */
        retval = 0xff;
        if (s->mixer_regs[0x82] & 2) {
            ack = 1;
            s->mixer_regs[0x82] &= 2;
            pic_set_irq (s->irq, 0);
        }
        break;

    default:
        goto error;
    }

    if (!ack) {
        ldebug ("read %#x -> %#x\n", nport, retval);
    }

    return retval;

 error:
    dolog ("warning: dsp_read %#x error\n", nport);
    return 0xff;
}

static void reset_mixer (SB16State *s)
{
    int i;

    memset (s->mixer_regs, 0xff, 0x7f);
    memset (s->mixer_regs + 0x83, 0xff, sizeof (s->mixer_regs) - 0x83);

    s->mixer_regs[0x02] = 4;    /* master volume 3bits */
    s->mixer_regs[0x06] = 4;    /* MIDI volume 3bits */
    s->mixer_regs[0x08] = 0;    /* CD volume 3bits */
    s->mixer_regs[0x0a] = 0;    /* voice volume 2bits */

    /* d5=input filt, d3=lowpass filt, d1,d2=input source */
    s->mixer_regs[0x0c] = 0;

    /* d5=output filt, d1=stereo switch */
    s->mixer_regs[0x0e] = 0;

    /* voice volume L d5,d7, R d1,d3 */
    s->mixer_regs[0x04] = (4 << 5) | (4 << 1);
    /* master ... */
    s->mixer_regs[0x22] = (4 << 5) | (4 << 1);
    /* MIDI ... */
    s->mixer_regs[0x26] = (4 << 5) | (4 << 1);

    for (i = 0x30; i < 0x48; i++) {
        s->mixer_regs[i] = 0x20;
    }
}

static IO_WRITE_PROTO(mixer_write_indexb)
{
    SB16State *s = opaque;
    (void) nport;
    s->mixer_nreg = val;
}

static IO_WRITE_PROTO(mixer_write_datab)
{
    SB16State *s = opaque;

    (void) nport;
    ldebug ("mixer_write [%#x] <- %#x\n", s->mixer_nreg, val);

    switch (s->mixer_nreg) {
    case 0x00:
        reset_mixer (s);
        break;

    case 0x80:
        {
            int irq = irq_of_magic (val);
            ldebug ("setting irq to %d (val=%#x)\n", irq, val);
            if (irq > 0) {
                s->irq = irq;
            }
        }
        break;

    case 0x81:
        {
            int dma, hdma;

            dma = lsbindex (val & 0xf);
            hdma = lsbindex (val & 0xf0);
            if (dma != s->dma || hdma != s->hdma) {
                dolog (
                    "attempt to change DMA "
                    "8bit %d(%d), 16bit %d(%d) (val=%#x)\n",
                    dma, s->dma, hdma, s->hdma, val);
            }
#if 0
            s->dma = dma;
            s->hdma = hdma;
#endif
        }
        break;

    case 0x82:
        dolog ("attempt to write into IRQ status register (val=%#x)\n",
               val);
        return;

    default:
        if (s->mixer_nreg >= 0x80) {
            ldebug ("attempt to write mixer[%#x] <- %#x\n", s->mixer_nreg, val);
        }
        break;
    }

    s->mixer_regs[s->mixer_nreg] = val;
}

static IO_WRITE_PROTO(mixer_write_indexw)
{
    mixer_write_indexb (opaque, nport, val & 0xff);
    mixer_write_datab (opaque, nport, (val >> 8) & 0xff);
}

static IO_READ_PROTO(mixer_read)
{
    SB16State *s = opaque;

    (void) nport;
#ifndef DEBUG_SB16_MOST
    if (s->mixer_nreg != 0x82) {
        ldebug ("mixer_read[%#x] -> %#x\n",
                s->mixer_nreg, s->mixer_regs[s->mixer_nreg]);
    }
#else
    ldebug ("mixer_read[%#x] -> %#x\n",
            s->mixer_nreg, s->mixer_regs[s->mixer_nreg]);
#endif
    return s->mixer_regs[s->mixer_nreg];
}

static int write_audio (SB16State *s, int nchan, int dma_pos,
                        int dma_len, int len)
{
    int temp, net;
    uint8_t tmpbuf[4096];

    temp = len;
    net = 0;

    while (temp) {
        int left = dma_len - dma_pos;
        int copied;
        size_t to_copy;

        to_copy = audio_MIN (temp, left);
        if (to_copy > sizeof (tmpbuf)) {
            to_copy = sizeof (tmpbuf);
        }

        copied = DMA_read_memory (nchan, tmpbuf, dma_pos, to_copy);
        copied = AUD_write (s->voice, tmpbuf, copied);

        temp -= copied;
        dma_pos = (dma_pos + copied) % dma_len;
        net += copied;

        if (!copied) {
            break;
        }
    }

    return net;
}

static int SB_read_DMA (void *opaque, int nchan, int dma_pos, int dma_len)
{
    SB16State *s = opaque;
    int till, copy, written, free;

    if (s->left_till_irq < 0) {
        s->left_till_irq = s->block_size;
    }

    if (s->voice) {
        free = s->audio_free & ~s->align;
        if ((free <= 0) || !dma_len) {
            return dma_pos;
        }
    }
    else {
        free = dma_len;
    }

    copy = free;
    till = s->left_till_irq;

#ifdef DEBUG_SB16_MOST
    dolog ("pos:%06d %d till:%d len:%d\n",
           dma_pos, free, till, dma_len);
#endif

    if (till <= copy) {
        if (0 == s->dma_auto) {
            copy = till;
        }
    }

    written = write_audio (s, nchan, dma_pos, dma_len, copy);
    dma_pos = (dma_pos + written) % dma_len;
    s->left_till_irq -= written;

    if (s->left_till_irq <= 0) {
        s->mixer_regs[0x82] |= (nchan & 4) ? 2 : 1;
        pic_set_irq (s->irq, 1);
        if (0 == s->dma_auto) {
            control (s, 0);
            speaker (s, 0);
        }
    }

#ifdef DEBUG_SB16_MOST
    ldebug ("pos %5d free %5d size %5d till % 5d copy %5d written %5d size %5d\n",
            dma_pos, free, dma_len, s->left_till_irq, copy, written,
            s->block_size);
#endif

    while (s->left_till_irq <= 0) {
        s->left_till_irq = s->block_size + s->left_till_irq;
    }

    return dma_pos;
}

static void SB_audio_callback (void *opaque, int free)
{
    SB16State *s = opaque;
    s->audio_free = free;
}

static void SB_save (QEMUFile *f, void *opaque)
{
    SB16State *s = opaque;

    qemu_put_be32s (f, &s->irq);
    qemu_put_be32s (f, &s->dma);
    qemu_put_be32s (f, &s->hdma);
    qemu_put_be32s (f, &s->port);
    qemu_put_be32s (f, &s->ver);
    qemu_put_be32s (f, &s->in_index);
    qemu_put_be32s (f, &s->out_data_len);
    qemu_put_be32s (f, &s->fmt_stereo);
    qemu_put_be32s (f, &s->fmt_signed);
    qemu_put_be32s (f, &s->fmt_bits);
    qemu_put_be32s (f, &s->fmt);
    qemu_put_be32s (f, &s->dma_auto);
    qemu_put_be32s (f, &s->block_size);
    qemu_put_be32s (f, &s->fifo);
    qemu_put_be32s (f, &s->freq);
    qemu_put_be32s (f, &s->time_const);
    qemu_put_be32s (f, &s->speaker);
    qemu_put_be32s (f, &s->needed_bytes);
    qemu_put_be32s (f, &s->cmd);
    qemu_put_be32s (f, &s->use_hdma);
    qemu_put_be32s (f, &s->highspeed);
    qemu_put_be32s (f, &s->can_write);
    qemu_put_be32s (f, &s->v2x6);

    qemu_put_8s (f, &s->csp_param);
    qemu_put_8s (f, &s->csp_value);
    qemu_put_8s (f, &s->csp_mode);
    qemu_put_8s (f, &s->csp_param);
    qemu_put_buffer (f, s->csp_regs, 256);
    qemu_put_8s (f, &s->csp_index);
    qemu_put_buffer (f, s->csp_reg83, 4);
    qemu_put_be32s (f, &s->csp_reg83r);
    qemu_put_be32s (f, &s->csp_reg83w);

    qemu_put_buffer (f, s->in2_data, sizeof (s->in2_data));
    qemu_put_buffer (f, s->out_data, sizeof (s->out_data));
    qemu_put_8s (f, &s->test_reg);
    qemu_put_8s (f, &s->last_read_byte);

    qemu_put_be32s (f, &s->nzero);
    qemu_put_be32s (f, &s->left_till_irq);
    qemu_put_be32s (f, &s->dma_running);
    qemu_put_be32s (f, &s->bytes_per_second);
    qemu_put_be32s (f, &s->align);

    qemu_put_be32s (f, &s->mixer_nreg);
    qemu_put_buffer (f, s->mixer_regs, 256);
}

static int SB_load (QEMUFile *f, void *opaque, int version_id)
{
    SB16State *s = opaque;

    if (version_id != 1) {
        return -EINVAL;
    }

    qemu_get_be32s (f, &s->irq);
    qemu_get_be32s (f, &s->dma);
    qemu_get_be32s (f, &s->hdma);
    qemu_get_be32s (f, &s->port);
    qemu_get_be32s (f, &s->ver);
    qemu_get_be32s (f, &s->in_index);
    qemu_get_be32s (f, &s->out_data_len);
    qemu_get_be32s (f, &s->fmt_stereo);
    qemu_get_be32s (f, &s->fmt_signed);
    qemu_get_be32s (f, &s->fmt_bits);
    qemu_get_be32s (f, &s->fmt);
    qemu_get_be32s (f, &s->dma_auto);
    qemu_get_be32s (f, &s->block_size);
    qemu_get_be32s (f, &s->fifo);
    qemu_get_be32s (f, &s->freq);
    qemu_get_be32s (f, &s->time_const);
    qemu_get_be32s (f, &s->speaker);
    qemu_get_be32s (f, &s->needed_bytes);
    qemu_get_be32s (f, &s->cmd);
    qemu_get_be32s (f, &s->use_hdma);
    qemu_get_be32s (f, &s->highspeed);
    qemu_get_be32s (f, &s->can_write);
    qemu_get_be32s (f, &s->v2x6);

    qemu_get_8s (f, &s->csp_param);
    qemu_get_8s (f, &s->csp_value);
    qemu_get_8s (f, &s->csp_mode);
    qemu_get_8s (f, &s->csp_param);
    qemu_get_buffer (f, s->csp_regs, 256);
    qemu_get_8s (f, &s->csp_index);
    qemu_get_buffer (f, s->csp_reg83, 4);
    qemu_get_be32s (f, &s->csp_reg83r);
    qemu_get_be32s (f, &s->csp_reg83w);

    qemu_get_buffer (f, s->in2_data, sizeof (s->in2_data));
    qemu_get_buffer (f, s->out_data, sizeof (s->out_data));
    qemu_get_8s (f, &s->test_reg);
    qemu_get_8s (f, &s->last_read_byte);

    qemu_get_be32s (f, &s->nzero);
    qemu_get_be32s (f, &s->left_till_irq);
    qemu_get_be32s (f, &s->dma_running);
    qemu_get_be32s (f, &s->bytes_per_second);
    qemu_get_be32s (f, &s->align);

    qemu_get_be32s (f, &s->mixer_nreg);
    qemu_get_buffer (f, s->mixer_regs, 256);

    if (s->voice) {
        AUD_close_out (&s->card, s->voice);
        s->voice = NULL;
    }

    if (s->dma_running) {
        if (s->freq) {
            audsettings_t as;

            s->audio_free = 0;

            as.freq = s->freq;
            as.nchannels = 1 << s->fmt_stereo;
            as.fmt = s->fmt;

            s->voice = AUD_open_out (
                &s->card,
                s->voice,
                "sb16",
                s,
                SB_audio_callback,
                &as,
                0               /* little endian */
                );
        }

        control (s, 1);
        speaker (s, s->speaker);
    }
    return 0;
}

int SB16_init (AudioState *audio)
{
    SB16State *s;
    int i;
    static const uint8_t dsp_write_ports[] = {0x6, 0xc};
    static const uint8_t dsp_read_ports[] = {0x6, 0xa, 0xc, 0xd, 0xe, 0xf};

    if (!audio) {
        dolog ("No audio state\n");
        return -1;
    }

    s = qemu_mallocz (sizeof (*s));
    if (!s) {
        dolog ("Could not allocate memory for SB16 (%zu bytes)\n",
               sizeof (*s));
        return -1;
    }

    s->cmd = -1;
    s->irq = conf.irq;
    s->dma = conf.dma;
    s->hdma = conf.hdma;
    s->port = conf.port;
    s->ver = conf.ver_lo | (conf.ver_hi << 8);

    s->mixer_regs[0x80] = magic_of_irq (s->irq);
    s->mixer_regs[0x81] = (1 << s->dma) | (1 << s->hdma);
    s->mixer_regs[0x82] = 2 << 5;

    s->csp_regs[5] = 1;
    s->csp_regs[9] = 0xf8;

    reset_mixer (s);
    s->aux_ts = qemu_new_timer (vm_clock, aux_timer, s);
    if (!s->aux_ts) {
        dolog ("warning: Could not create auxiliary timer\n");
    }

    for (i = 0; i < LENOFA (dsp_write_ports); i++) {
        register_ioport_write (s->port + dsp_write_ports[i], 1, 1, dsp_write, s);
    }

    for (i = 0; i < LENOFA (dsp_read_ports); i++) {
        register_ioport_read (s->port + dsp_read_ports[i], 1, 1, dsp_read, s);
    }

    register_ioport_write (s->port + 0x4, 1, 1, mixer_write_indexb, s);
    register_ioport_write (s->port + 0x4, 1, 2, mixer_write_indexw, s);
    register_ioport_read (s->port + 0x5, 1, 1, mixer_read, s);
    register_ioport_write (s->port + 0x5, 1, 1, mixer_write_datab, s);

    DMA_register_channel (s->hdma, SB_read_DMA, s);
    DMA_register_channel (s->dma, SB_read_DMA, s);
    s->can_write = 1;

    register_savevm ("sb16", 0, 1, SB_save, SB_load, s);
    AUD_register_card (audio, "sb16", &s->card);
    return 0;
}