102 lines
3.0 KiB
C
102 lines
3.0 KiB
C
#include <pico/stdlib.h>
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#include "common/config.h"
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#include "vga/hires_color_patterns.h"
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#include "vga/hires_dot_patterns.h"
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#include "vga/vgabuf.h"
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#include "vga/render.h"
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#include "vga/vgaout.h"
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static void render_shr_line(uint16_t line);
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#ifdef ANALOG_GS
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#define rgb444(a) (a)
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#else
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static inline uint16_t rgb444(uint16_t a) {
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return ((a & 0xe00) >> 3) | ((a & 0xe0) >> 2) | ((a & 0xe) >> 1);
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}
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#endif
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void DELAYED_COPY_CODE(render_shr)() {
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vga_prepare_frame();
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render_border(40);
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for(uint line=0; line < 200; line++) {
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render_shr_line(line);
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}
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render_border(40);
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}
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static void DELAYED_COPY_CODE(render_shr_line)(uint16_t line) {
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struct vga_scanline *sl = vga_prepare_scanline();
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uint sl_pos = 0;
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uint i;
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uint8_t control = private_memory[0x9D00 + line];
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uint32_t line_palette_offset = (control & 0xF) << 5;
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volatile uint16_t *shr_palette = (volatile uint16_t*)(private_memory + 0x9E00 + line_palette_offset);
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volatile uint8_t *line_mem = (volatile uint8_t *)(private_memory + 0x2000 + (line * 160));
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// SHR is weird. Nuff said.
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uint32_t dots = 0;
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uint32_t pixeldata;
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uint16_t color_a = 0, color_b = 0;
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int j;
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i = 0;
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if(control & 0x80) { // 640 Pixels
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while(i < 160) {
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// Load in the next 2 pixels
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dots = (line_mem[i++] & 0xff);
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color_a = ((dots >> 4) & 0xf);
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color_b = ((dots >> 0) & 0xf);
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// Consume 2 pixels
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pixeldata = rgb444(shr_palette[color_a]) | THEN_EXTEND_1;
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pixeldata |= (rgb444(shr_palette[color_b]) | THEN_EXTEND_1) << 16;
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sl->data[sl_pos++] = pixeldata;
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}
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} else if(control & 0x40) { // 320 Pixels w/ color fill
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while(i < 160) {
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// Load in the next 4 subpixels
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dots = (line_mem[i++] & 0xff);
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// Consume 2 pixels
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if(dots & 0xf0) {
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color_a = ((dots >> 4) & 0xf);
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} else {
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color_a = color_b;
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}
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if(dots & 0x0f) {
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color_b = ((dots >> 0) & 0xf);
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} else {
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color_b = color_a;
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}
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pixeldata = rgb444(shr_palette[color_a]) | THEN_EXTEND_1;
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pixeldata |= (rgb444(shr_palette[color_b]) | THEN_EXTEND_1) << 16;
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sl->data[sl_pos++] = pixeldata;
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}
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} else { // 320 Pixels
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while(i < 160) {
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// Load in the next 2 pixels
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dots = (line_mem[i++] & 0xff);
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color_a = ((dots >> 4) & 0xf);
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color_b = ((dots >> 0) & 0xf);
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// Consume 2 pixels
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pixeldata = rgb444(shr_palette[color_a]) | THEN_EXTEND_1;
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pixeldata |= (rgb444(shr_palette[color_b]) | THEN_EXTEND_1) << 16;
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sl->data[sl_pos++] = pixeldata;
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}
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}
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sl->length = sl_pos;
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sl->repeat_count = 1;
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vga_submit_scanline(sl);
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}
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