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mirror of https://github.com/TomHarte/CLK.git synced 2024-11-22 12:33:29 +00:00

Improves use of const.

This commit is contained in:
Thomas Harte 2019-02-18 20:21:41 -05:00
parent 40ee215b1b
commit ac8d43cc4a

View File

@ -66,10 +66,10 @@ void VideoOutput::set_colour_rom(const std::vector<uint8_t> &rom) {
// Values in the ROM are encoded for indexing by two square waves
// in quadrature, which means that they're indexed in the order
// 0, 1, 3, 2.
colour[1] = uint8_t(rom[index] & 0xf0);
colour[0] = uint8_t((rom[index] & 0x0f) << 4);
colour[3] = uint8_t((rom[index+1] & 0x0f) << 4);
colour[1] = uint8_t(rom[index] & 0xf0);
colour[2] = uint8_t(rom[index+1] & 0xf0);
colour[3] = uint8_t((rom[index+1] & 0x0f) << 4);
// Extracting just the visible part of the stored range of values
// means etracting the range 0x40 to 0xe0.
@ -79,12 +79,12 @@ void VideoOutput::set_colour_rom(const std::vector<uint8_t> &rom) {
}
// Check for big endianness and byte swap if required.
uint32_t test_value = 0x0001;
if(*reinterpret_cast<uint8_t *>(&test_value) != 0x01) {
// uint32_t test_value = 0x0001;
// if(*reinterpret_cast<uint8_t *>(&test_value) != 0x01) {
// for(std::size_t c = 0; c < 8; c++) {
// colour_forms_[c] = static_cast<uint16_t>((colour_forms_[c] >> 8) | (colour_forms_[c] << 8));
// }
}
// }
}
void VideoOutput::run_for(const Cycles cycles) {
@ -130,7 +130,7 @@ void VideoOutput::run_for(const Cycles cycles) {
int columns = cycles_run_for;
int pixel_base_address = 0xa000 + (counter_ >> 6) * 40;
int character_base_address = 0xbb80 + (counter_ >> 9) * 40;
uint8_t blink_mask = (blink_text_ && (frame_counter_&32)) ? 0x00 : 0xff;
const uint8_t blink_mask = (blink_text_ && (frame_counter_&32)) ? 0x00 : 0xff;
while(columns--) {
uint8_t pixels, control_byte;
@ -140,11 +140,11 @@ void VideoOutput::run_for(const Cycles cycles) {
} else {
int address = character_base_address + h_counter;
control_byte = ram_[address];
int line = use_double_height_characters_ ? ((counter_ >> 7) & 7) : ((counter_ >> 6) & 7);
const int line = use_double_height_characters_ ? ((counter_ >> 7) & 7) : ((counter_ >> 6) & 7);
pixels = ram_[character_set_base_address_ + (control_byte&127) * 8 + line];
}
uint8_t inverse_mask = (control_byte & 0x80) ? 0x7 : 0x0;
const uint8_t inverse_mask = (control_byte & 0x80) ? 0x7 : 0x0;
pixels &= blink_mask;
if(control_byte & 0x60) {