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Adds support for fill mode.

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This commit is contained in:
Thomas Harte 2020-11-22 21:55:21 -05:00
parent 8ace258fbc
commit 46f7ff07f7
2 changed files with 16 additions and 7 deletions
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20
Machines/Apple/AppleIIgs/Video.cpp
View File

@ -235,6 +235,11 @@ void VideoBase::output_row(int row, int start, int end) {
set_interrupts(0x20);
}
// Set up appropriately for fill mode (or not).
for(int c = 0; c < 4; c++) {
palette_zero_[c] = (line_control_ & 0x20) ? &palette_[c * 4] : &palette_throwaway_;
}
// Reset NTSC decoding and total line buffering.
ntsc_delay_ = 4;
pixels_start_column_ = start;
@ -431,21 +436,22 @@ uint16_t *VideoBase::output_double_text(uint16_t *target, int start, int end, in
uint16_t *VideoBase::output_super_high_res(uint16_t *target, int start, int end, int row) const {
const int row_address = row * 160 + 0x12000;
// TODO: line_control_ & 0x20 should enable or disable colour fill mode.
// The palette_zero_ writes ensure that palette colour 0 is replaced by whatever was last output,
// if fill mode is enabled. Otherwise they go to throwaway storage.
if(line_control_ & 0x80) {
for(int c = start * 4; c < end * 4; c++) {
const uint8_t source = ram_[row_address + c];
target[0] = palette_[0x8 + ((source >> 6) & 0x3)];
target[1] = palette_[0xc + ((source >> 4) & 0x3)];
target[2] = palette_[0x0 + ((source >> 2) & 0x3)];
target[3] = palette_[0x4 + ((source >> 0) & 0x3)];
*palette_zero_[3] = target[0] = palette_[0x8 + ((source >> 6) & 0x3)];
*palette_zero_[0] = target[1] = palette_[0xc + ((source >> 4) & 0x3)];
*palette_zero_[1] = target[2] = palette_[0x0 + ((source >> 2) & 0x3)];
*palette_zero_[2] = target[3] = palette_[0x4 + ((source >> 0) & 0x3)];
target += 4;
}
} else {
for(int c = start * 4; c < end * 4; c++) {
const uint8_t source = ram_[row_address + c];
target[0] = palette_[(source >> 4) & 0xf];
target[1] = palette_[source & 0xf];
*palette_zero_[0] = target[0] = palette_[(source >> 4) & 0xf];
*palette_zero_[0] = target[1] = palette_[source & 0xf];
target += 2;
}
}

3
Machines/Apple/AppleIIgs/Video.hpp
View File

@ -144,6 +144,9 @@ class VideoBase: public Apple::II::VideoSwitches<Cycles> {
uint8_t line_control_;
uint16_t palette_[16];
// Storage used for fill mode.
uint16_t *palette_zero_[4] = {nullptr, nullptr, nullptr, nullptr}, palette_throwaway_;
// Lookup tables and state to assist in the IIgs' mapping from NTSC to RGB.
//
// My understanding of the real-life algorithm is: maintain a four-bit buffer.