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Implement VGA DAC color palette read. Fixes #58

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copy 2015-04-30 03:01:36 +02:00
parent 62704f9aea
commit d335931869
1 changed files with 18 additions and 5 deletions
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23
src/vga.js
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@ -139,7 +139,8 @@ function VGAScreen(cpu, bus, vga_memory_size)
this.index_crtc = 0;
// index for setting colors through port 3C9h
this.dac_color_index = 0;
this.dac_color_index_write = 0;
this.dac_color_index_read = 0;
this.attribute_controller_index = -1;
@ -184,6 +185,7 @@ function VGAScreen(cpu, bus, vga_memory_size)
io.register_write(0x3C7, this, this.port3C7_write);
io.register_write(0x3C8, this, this.port3C8_write);
io.register_write(0x3C9, this, this.port3C9_write);
io.register_read(0x3C9, this, this.port3C9_read);
io.register_read(0x3CC, this, this.port3CC_read);
@ -813,17 +815,18 @@ VGAScreen.prototype.port3C7_write = function(index)
{
// index for reading the DAC
dbg_log("3C7 write: " + h(index), LOG_VGA);
this.dac_color_index_read = index * 3;
};
VGAScreen.prototype.port3C8_write = function(index)
{
this.dac_color_index = index * 3;
this.dac_color_index_write = index * 3;
};
VGAScreen.prototype.port3C9_write = function(color_byte)
{
var index = this.dac_color_index / 3 | 0,
offset = this.dac_color_index % 3,
var index = this.dac_color_index_write / 3 | 0,
offset = this.dac_color_index_write % 3,
color = this.vga256_palette[index];
color_byte = color_byte * 255 / 63 & 0xFF;
@ -843,12 +846,22 @@ VGAScreen.prototype.port3C9_write = function(color_byte)
}
this.vga256_palette[index] = color;
this.dac_color_index++;
this.dac_color_index_write++;
// Needs to be throttled:
//this.complete_redraw();
};
VGAScreen.prototype.port3C9_read = function()
{
var index = this.dac_color_index_read / 3 | 0;
var offset = this.dac_color_index_read % 3;
var color = this.vga256_palette[index];
this.dac_color_index_read++;
return (color >> (2 - offset) * 8 & 0xFF) / 255 * 63 | 0;
}
VGAScreen.prototype.port3CC_read = function()
{
return this.miscellaneous_output_register;