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Implement DMA autoinit mode

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Ernest Wong 2017-11-19 16:29:29 +13:00 committed by Fabian
parent 43bc6836fc
commit 7733452fa8
1 changed files with 49 additions and 15 deletions
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64
src/dma.js
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@ -9,9 +9,11 @@ function DMA(cpu)
/** @const @type {CPU} */
this.cpu = cpu;
this.channel_addr = new Uint16Array(8);
this.channel_page = new Uint8Array(8);
this.channel_addr = new Uint16Array(8);
this.channel_addr_init = new Uint16Array(8);
this.channel_count = new Int32Array(8);
this.channel_count_init = new Int32Array(8);
this.channel_mask = new Uint8Array(8);
this.channel_mode = new Uint8Array(8);
this.channel_on_unmask = [];
@ -108,7 +110,12 @@ DMA.prototype.set_state = function(state)
DMA.prototype.port_count_write = function(channel, data_byte)
{
dbg_log("count write [" + channel + "] = " + h(data_byte), LOG_DMA);
this.channel_count[channel] = this.flipflop_get(this.channel_count[channel], data_byte);
this.channel_count[channel] =
this.flipflop_get(this.channel_count[channel], data_byte, false);
this.channel_count_init[channel] =
this.flipflop_get(this.channel_count_init[channel], data_byte, true);
}
DMA.prototype.port_count_read = function(channel)
@ -120,7 +127,12 @@ DMA.prototype.port_count_read = function(channel)
DMA.prototype.port_addr_write = function(channel, data_byte)
{
dbg_log("addr write [" + channel + "] = " + h(data_byte), LOG_DMA);
this.channel_addr[channel] = this.flipflop_get(this.channel_addr[channel], data_byte);
this.channel_addr[channel] =
this.flipflop_get(this.channel_addr[channel], data_byte, false);
this.channel_addr_init[channel] =
this.flipflop_get(this.channel_addr_init[channel], data_byte, true);
}
DMA.prototype.port_addr_read = function(channel)
@ -267,7 +279,7 @@ DMA.prototype.port81_write = function(data_byte)
// read data, write to memory
DMA.prototype.do_read = function(buffer, start, len, channel, fn)
{
var read_count = this.count_get_8bit(channel) + 1,
var read_count = this.count_get_8bit(channel),
addr = this.address_get_8bit(channel);
dbg_log("DMA write channel " + channel, LOG_DMA);
@ -297,25 +309,36 @@ DMA.prototype.do_read = function(buffer, start, len, channel, fn)
};
// write data, read memory
// start and len in bytes
DMA.prototype.do_write = function(buffer, start, len, channel, fn)
{
var read_count = this.count_get_8bit(channel),
addr = this.address_get_8bit(channel);
var read_count = this.channel_count[channel] + 1,
read_bytes = read_count,
addr = this.address_get_8bit(channel),
unfinished = false,
autoinit = this.channel_mode[channel] & 0x10;
if(channel >= 5)
{
// convert word count to byte count
read_bytes *= 2;
}
dbg_log("DMA write channel " + channel, LOG_DMA);
dbg_log("to " + h(addr) + " len " + h(read_count), LOG_DMA);
dbg_log("to " + h(addr) + " len " + h(read_bytes), LOG_DMA);
if(len < read_count)
if(len < read_bytes)
{
dbg_log("DMA should read more than provided", LOG_DMA);
read_count = len;
read_bytes = len;
unfinished = true;
}
else if(len > read_count)
else if(len > read_bytes)
{
dbg_log("DMA attempted to read more than provided", LOG_DMA);
}
if(start + read_count > buffer.byteLength)
if(start + read_bytes > buffer.byteLength)
{
dbg_log("DMA write outside of buffer", LOG_DMA);
fn(true);
@ -323,9 +346,17 @@ DMA.prototype.do_write = function(buffer, start, len, channel, fn)
else
{
this.channel_addr[channel] += read_count;
this.channel_count[channel] -= read_count;
// when complete, counter should underflow to 0xFFFF
if(!unfinished && autoinit)
{
this.channel_addr[channel] = this.channel_addr_init[channel];
this.channel_count[channel] = this.channel_count_init[channel];
}
buffer.set(start,
this.cpu.mem8.subarray(addr, addr + read_count + 1),
this.cpu.mem8.subarray(addr, addr + read_count),
function() {
fn(false);
}
@ -351,7 +382,7 @@ DMA.prototype.address_get_8bit = function(channel)
DMA.prototype.count_get_8bit = function(channel)
{
var count = this.channel_count[channel];
var count = this.channel_count[channel] + 1;
if(channel >= 5)
{
@ -361,9 +392,12 @@ DMA.prototype.count_get_8bit = function(channel)
return count;
}
DMA.prototype.flipflop_get = function(old_dword, new_byte)
DMA.prototype.flipflop_get = function(old_dword, new_byte, continuing)
{
this.lsb_msb_flipflop ^= 1;
if(!continuing)
{
this.lsb_msb_flipflop ^= 1;
}
if(this.lsb_msb_flipflop)
{