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Makes substantial optimisations to text mode.

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Character optimisations to come.
This commit is contained in:
Thomas Harte 2017-12-04 22:18:51 -05:00
parent ec266d6c8e
commit 6eedc99286
2 changed files with 189 additions and 190 deletions
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78
Components/9918/9918.cpp
View File

@ -103,38 +103,27 @@ void TMS9918::run_for(const HalfCycles cycles) {
const int access_slot = column_ >> 1; // There are only 171 available memory accesses per line.
switch(line_mode_) {
case LineMode::Text:
while(access_pointer_ < access_slot) {
if(access_pointer_ < 29) {
access_pointer_ = std::min(29, access_slot);
}
if(access_pointer_ >= 29) {
int row_base = pattern_name_address_ + (row_ >> 3) * 40;
int character_column = (access_pointer_ - 29) / 3;
access_pointer_ = std::min(30, access_slot);
if(access_pointer_ >= 30 && access_pointer_ < 150) {
const int row_base = pattern_name_address_ + (row_ >> 3) * 40;
const int start_column = (access_pointer_ - 30) / 3;
const int end = std::min(150, access_slot);
const int end = std::min(149, access_slot);
// Pattern names are collected every third window starting from window 30.
const int pattern_names_end = (end - 30) / 3;
for(int column = start_column; column < pattern_names_end; ++column) {
pattern_names_[column] = ram_[row_base + column];
}
while(access_pointer_ < end) {
switch(access_pointer_%3) {
case 0:
pattern_buffer_[character_column] = ram_[pattern_generator_table_address_ + (pattern_name_ << 3) + (row_ & 7)];
character_column++;
break;
case 1: break; // TODO: CPU access.
case 2:
pattern_name_ = ram_[row_base + character_column];
break;
}
access_pointer_++;
}
}
if(access_pointer_ >= 149) {
access_pointer_ = access_slot;
// Patterns are collected every third window starting from window 32.
const int pattern_buffer_end = (end - 32) / 3;
for(int column = start_column; column < pattern_buffer_end; ++column) {
pattern_buffer_[column] = ram_[pattern_generator_table_address_ + (pattern_names_[column] << 3) + (row_ & 7)];
}
}
break;
case LineMode::Character:
while(access_pointer_ < access_slot) {
// Four access windows: no collection.
access_pointer_ = std::min(4, access_slot);
@ -147,7 +136,6 @@ void TMS9918::run_for(const HalfCycles cycles) {
const int target = 2 + (offset / 6);
const int sprite = active_sprites_[target] & 31;
const int subcycle = offset % 6;
// printf("%d: %d %d\n", access_pointer_, target, subcycle);
switch(subcycle) {
case 0: sprites_[target].y = ram_[sprite_attribute_table_address_ + (sprite << 2)]; break;
case 1: sprites_[target].x = ram_[sprite_attribute_table_address_ + (sprite << 2) + 1]; break;
@ -203,7 +191,7 @@ void TMS9918::run_for(const HalfCycles cycles) {
int character_column = ((access_pointer_ - 26) >> 2);
switch(access_pointer_&3) {
case 2:
pattern_name_ = ram_[row_base + character_column];
pattern_names_[character_column] = ram_[row_base + character_column];
break;
case 3: {
const int slot = (access_pointer_ - 31) >> 2;
@ -214,13 +202,13 @@ void TMS9918::run_for(const HalfCycles cycles) {
} break;
case 0:
if(screen_mode_ != 1) {
colour_buffer_[character_column] = ram_[colour_base + (pattern_name_ >> 3)];
colour_buffer_[character_column] = ram_[colour_base + (pattern_names_[character_column] >> 3)];
} else {
colour_buffer_[character_column] = ram_[colour_base + (pattern_name_ << 3) + (row_ & 7)];
colour_buffer_[character_column] = ram_[colour_base + (pattern_names_[character_column] << 3) + (row_ & 7)];
}
break;
case 1:
pattern_buffer_[character_column] = ram_[pattern_base + (pattern_name_ << 3) + (row_ & 7)];
pattern_buffer_[character_column] = ram_[pattern_base + (pattern_names_[character_column] << 3) + (row_ & 7)];
break;
}
access_pointer_++;
@ -272,7 +260,6 @@ void TMS9918::run_for(const HalfCycles cycles) {
const int target = (access_pointer_ - 156) / 6;
const int sprite = active_sprites_[target] & 31;
const int subcycle = access_pointer_ % 6;
// printf("%d: %d %d\n", access_pointer_, target, subcycle);
switch(subcycle) {
case 0: sprites_[target].y = ram_[sprite_attribute_table_address_ + (sprite << 2)]; break;
case 1: sprites_[target].x = ram_[sprite_attribute_table_address_ + (sprite << 2) + 1]; break;
@ -293,7 +280,6 @@ void TMS9918::run_for(const HalfCycles cycles) {
// There's a single unused access window here.
access_pointer_ = std::min(171, access_slot);
}
break;
}
}
@ -344,17 +330,29 @@ void TMS9918::run_for(const HalfCycles cycles) {
if(output_column_ < pixels_end) {
switch(line_mode_) {
case LineMode::Text:
while(output_column_ < pixels_end) {
const int base = (output_column_ - first_pixel_column_);
const int address = base / 6;
const int pattern = pattern_buffer_[address] << (base % 6);
case LineMode::Text: {
const uint32_t colours[2] = { palette[background_colour_], palette[text_colour_] };
*pixel_target_ = (pattern&0x80) ? palette[text_colour_] : palette[background_colour_];
const int shift = (output_column_ - first_pixel_column_) % 6;
int byte_column = (output_column_ - first_pixel_column_) / 6;
int pattern = pattern_buffer_[byte_column] << shift;
int pixels_left = pixels_end - output_column_;
int length = std::min(pixels_left, 6 - shift);
while(true) {
pixels_left -= length;
while(length--) {
*pixel_target_ = colours[(pattern >> 7)&0x01];
pixel_target_++;
output_column_ ++;
pattern <<= 1;
}
break;
if(!pixels_left) break;
length = std::min(6, pixels_left);
byte_column++;
pattern = pattern_buffer_[byte_column];
}
output_column_ = pixels_end;
} break;
case LineMode::Character:
while(output_column_ < pixels_end) {

3
Components/9918/9918.hpp
View File

@ -93,12 +93,13 @@ class TMS9918 {
} line_mode_ = LineMode::Text;
int first_pixel_column_, first_right_border_column_;
uint8_t pattern_names_[40];
uint8_t pattern_buffer_[40];
uint8_t colour_buffer_[40];
uint8_t sprite_locations_[32];
int active_sprites_[4];
int access_pointer_ = 0;
uint8_t pattern_name_ = 0;
struct Sprite {
uint8_t x, y;