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Make DMA on_unmask states restorable

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Instead of registering an on_unmask listener every time we want a
transfer, and unregistering the listener every time we're done with it,
SB16 now registers a handler during init, and keeps this handler
registered throughout the session. The handler function is moved to SB16's
prototype.

The dma_waiting_transfer flag indicates whether the handler should
actually carry out the transfer.
This commit is contained in:
Ernest Wong 2017-12-12 11:08:32 +13:00 committed by Fabian
parent 1c092c215c
commit dd7f845e57
2 changed files with 43 additions and 23 deletions
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21
src/dma.js
View file

@ -17,7 +17,7 @@ function DMA(cpu)
this.channel_count_init = new Uint16Array(8);
this.channel_mask = new Uint8Array(8);
this.channel_mode = new Uint8Array(8);
this.channel_on_unmask = [];
this.unmask_listeners = [];
this.lsb_msb_flipflop = 0;
@ -235,9 +235,12 @@ DMA.prototype.portC_write = function(data_byte)
this.lsb_msb_flipflop = 0;
};
DMA.prototype.on_unmask = function(channel, fn)
DMA.prototype.on_unmask = function(fn, this_value)
{
this.channel_on_unmask[channel] = fn;
this.unmask_listeners.push({
fn: fn,
this_value: this_value,
});
};
DMA.prototype.update_mask = function(channel, value)
@ -246,10 +249,16 @@ DMA.prototype.update_mask = function(channel, value)
{
this.channel_mask[channel] ^= 1;
if(!value && this.channel_on_unmask[channel])
if(!value)
{
dbg_log("firing on_unmask[" + channel + "]", LOG_DMA);
this.channel_on_unmask[channel]();
dbg_log("firing on_unmask(" + channel + ")", LOG_DMA);
for(var i = 0; i < this.unmask_listeners.length; i++)
{
this.unmask_listeners[i].fn.call(
this.unmask_listeners[i].this_value,
channel
);
}
}
}
};

45
src/sb16.js
View file

@ -143,6 +143,7 @@ function SB16(cpu, bus)
this.dma_buffer_int16 = new Int16Array(this.dma_buffer);
this.dma_buffer_uint16 = new Uint16Array(this.dma_buffer);
this.dma_syncbuffer = new SyncBuffer(this.dma_buffer);
this.dma_waiting_transfer = false;
this.sampling_rate = 22050;
this.bytes_per_sample = 1;
@ -212,6 +213,8 @@ function SB16(cpu, bus)
cpu.io.register_write(0x330, this, this.port3x0_write);
cpu.io.register_write(0x331, this, this.port3x1_write);
this.dma.on_unmask(this.dma_on_unmask, this);
bus.register("speaker-tell-samplerate", function(rate)
{
this.audio_samplerate = rate;
@ -256,6 +259,7 @@ SB16.prototype.reset_dsp = function()
this.dma_channel = 0;
this.dma_autoinit = false;
this.dma_buffer_uint8.fill(0);
this.dma_waiting_transfer = false;
this.e2_value = 0xAA;
this.e2_count = 0;
@ -306,20 +310,21 @@ SB16.prototype.get_state = function()
state[22] = this.dma_channel_16bit;
state[23] = this.dma_autoinit;
state[24] = this.dma_buffer_uint8;
state[25] = this.sampling_rate;
state[26] = this.bytes_per_sample;
state[25] = this.dma_waiting_transfer;
state[26] = this.sampling_rate;
state[27] = this.bytes_per_sample;
state[27] = this.e2_value;
state[28] = this.e2_count;
state[28] = this.e2_value;
state[29] = this.e2_count;
state[29] = this.asp_registers;
state[30] = this.asp_registers;
// state[30] = this.mpu_read_buffer;
state[31] = this.mpu_read_buffer_last_value;
// state[31] = this.mpu_read_buffer;
state[32] = this.mpu_read_buffer_last_value;
state[32] = this.irq;
state[33] = this.irq_triggered;
state[34] = this.audio_samplerate;
state[33] = this.irq;
state[34] = this.irq_triggered;
state[35] = this.audio_samplerate;
return state;
};
@ -1413,16 +1418,22 @@ SB16.prototype.dma_transfer_start = function()
this.dma_bytes_count = this.dma_sample_count * this.bytes_per_sample;
this.dma_bytes_block = DMA_BLOCK_SAMPLES * this.bytes_per_sample;
// (2) Configure amount of bytes left to transfer and begin first
// block of transfer when the DMA channel has been unmasked.
// (2) Wait for unmask event.
this.dma_waiting_transfer = true;
};
this.dma.on_unmask(this.dma_channel, () =>
SB16.prototype.dma_on_unmask = function(channel)
{
if(channel !== this.dma_channel || !this.dma_waiting_transfer)
{
this.dma.on_unmask(this.dma_channel, undefined);
this.dma_bytes_left = this.dma_bytes_count;
return;
}
this.dma_transfer_next();
});
// (3) Configure amount of bytes left to transfer and begin first
// block of transfer when the DMA channel has been unmasked.
this.dma_waiting_transfer = false;
this.dma_bytes_left = this.dma_bytes_count;
this.dma_transfer_next();
};
SB16.prototype.dma_transfer_next = function()