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Attempts to implement LSBALT and MSBALT.

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This commit is contained in:
Thomas Harte 2021-06-19 21:57:26 -04:00
parent 4968ccf46d
commit fadb04f3f3
2 changed files with 60 additions and 27 deletions
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86
Machines/Enterprise/Nick.cpp
View File

@ -159,15 +159,41 @@ void Nick::run_for(Cycles duration) {
palette_[c] = mapped_colour(line_parameters_[8 + c]);
}
// Use ALTIND0 and ALTIND1 to pick the alt_ind_palettes.
//
// ALTIND1 = b6 of params[3], if set => character codes with bit 7 set should use palette indices 2 and 3.
// ALTIND0 = b7 of params[3], if set => character codes with bit 6 set should use palette indices 4... instead of 0... .
alt_ind_palettes[0] = palette_;
alt_ind_palettes[2] = alt_ind_palettes[0] + ((line_parameters_[3] & 0x40) ? 2 : 0);
switch(mode_) {
default:
break;
alt_ind_palettes[1] = alt_ind_palettes[0] + ((line_parameters_[3] & 0x80) ? 4 : 0);
alt_ind_palettes[3] = alt_ind_palettes[2] + ((line_parameters_[3] & 0x80) ? 4 : 0);
// NB: LSBALT/MSBALT and ALTIND0/ALTIND1 appear to have opposite effects on palette selection.
case Mode::Pixel:
case Mode::LPixel:
// Use MSBALT and LSBALT to pick the alt_ind_palettes.
//
// LSBALT = b6 of params[2], if set => character codes with bit 6 set should use palette indices 4... instead of 0... .
// MSBALT = b7 of params[2], if set => character codes with bit 7 set should use palette indices 2 and 3.
two_colour_mask_ = 0xff &~ (((line_parameters_[2]&0x80) >> 7) | ((line_parameters_[2]&0x40) << 1));
alt_ind_palettes[0] = palette_;
alt_ind_palettes[2] = alt_ind_palettes[0] + ((line_parameters_[2] & 0x80) ? 2 : 0);
alt_ind_palettes[1] = alt_ind_palettes[0] + ((line_parameters_[2] & 0x40) ? 4 : 0);
alt_ind_palettes[3] = alt_ind_palettes[2] + ((line_parameters_[2] & 0x40) ? 4 : 0);
break;
case Mode::CH64:
case Mode::CH128:
case Mode::CH256:
// Use ALTIND0 and ALTIND1 to pick the alt_ind_palettes.
//
// ALTIND1 = b6 of params[3], if set => character codes with bit 7 set should use palette indices 2 and 3.
// ALTIND0 = b7 of params[3], if set => character codes with bit 6 set should use palette indices 4... instead of 0... .
alt_ind_palettes[0] = palette_;
alt_ind_palettes[2] = alt_ind_palettes[0] + ((line_parameters_[3] & 0x40) ? 2 : 0);
alt_ind_palettes[1] = alt_ind_palettes[0] + ((line_parameters_[3] & 0x80) ? 4 : 0);
alt_ind_palettes[3] = alt_ind_palettes[2] + ((line_parameters_[3] & 0x80) ? 4 : 0);
break;
}
}
}
@ -382,36 +408,42 @@ template <int bpp, bool is_lpixel> void Nick::output_pixel(uint16_t *target, int
static_assert(bpp == 1 || bpp == 2 || bpp == 4 || bpp == 8);
for(int c = 0; c < columns; c++) {
const uint8_t pixels[2] = { ram_[line_data_pointer_[0]], ram_[(line_data_pointer_[0]+1) & 0xffff] };
uint8_t pixels[2] = { ram_[line_data_pointer_[0]], ram_[(line_data_pointer_[0]+1) & 0xffff] };
line_data_pointer_[0] += is_lpixel ? 1 : 2;
switch(bpp) {
default:
case 1:
target[0] = palette_[(pixels[0] & 0x80) >> 7];
target[1] = palette_[(pixels[0] & 0x40) >> 6];
target[2] = palette_[(pixels[0] & 0x20) >> 5];
target[3] = palette_[(pixels[0] & 0x10) >> 4];
target[4] = palette_[(pixels[0] & 0x08) >> 3];
target[5] = palette_[(pixels[0] & 0x04) >> 2];
target[6] = palette_[(pixels[0] & 0x02) >> 1];
target[7] = palette_[(pixels[0] & 0x01) >> 0];
case 1: {
const uint16_t *palette = alt_ind_palettes[((pixels[0] >> 6) & 0x02) | (pixels[0]&1)];
pixels[0] &= two_colour_mask_;
target[0] = palette[(pixels[0] & 0x80) >> 7];
target[1] = palette[(pixels[0] & 0x40) >> 6];
target[2] = palette[(pixels[0] & 0x20) >> 5];
target[3] = palette[(pixels[0] & 0x10) >> 4];
target[4] = palette[(pixels[0] & 0x08) >> 3];
target[5] = palette[(pixels[0] & 0x04) >> 2];
target[6] = palette[(pixels[0] & 0x02) >> 1];
target[7] = palette[(pixels[0] & 0x01) >> 0];
if constexpr (!is_lpixel) {
target[8] = palette_[(pixels[1] & 0x80) >> 7];
target[9] = palette_[(pixels[1] & 0x40) >> 6];
target[10] = palette_[(pixels[1] & 0x20) >> 5];
target[11] = palette_[(pixels[1] & 0x10) >> 4];
target[12] = palette_[(pixels[1] & 0x08) >> 3];
target[13] = palette_[(pixels[1] & 0x04) >> 2];
target[14] = palette_[(pixels[1] & 0x02) >> 1];
target[15] = palette_[(pixels[1] & 0x01) >> 0];
palette = alt_ind_palettes[((pixels[1] >> 6) & 0x02) | (pixels[1]&1)];
pixels[1] &= two_colour_mask_;
target[8] = palette[(pixels[1] & 0x80) >> 7];
target[9] = palette[(pixels[1] & 0x40) >> 6];
target[10] = palette[(pixels[1] & 0x20) >> 5];
target[11] = palette[(pixels[1] & 0x10) >> 4];
target[12] = palette[(pixels[1] & 0x08) >> 3];
target[13] = palette[(pixels[1] & 0x04) >> 2];
target[14] = palette[(pixels[1] & 0x02) >> 1];
target[15] = palette[(pixels[1] & 0x01) >> 0];
target += 8;
}
target += 8;
break;
} break;
case 2:
target[0] = palette_[((pixels[0] & 0x80) >> 6) | ((pixels[0] & 0x08) >> 3)];

1
Machines/Enterprise/Nick.hpp
View File

@ -55,6 +55,7 @@ class Nick {
// Current mode line parameters.
uint8_t lines_remaining_ = 0x00;
uint8_t two_colour_mask_ = 0xff;
int left_margin_ = 0, right_margin_ = 0;
const uint16_t *alt_ind_palettes[4];
enum class Mode {