92 lines
2.2 KiB
C
92 lines
2.2 KiB
C
#include <stddef.h>
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#include <stdint.h>
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#include <brados/string.h>
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#include <video/vga.h>
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// Create a VGA color
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uint8_t make_color(enum vga_color fg, enum vga_color bg)
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{
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return fg | bg << 4;
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}
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// Create a VGA character
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uint16_t make_vgaEntry(char c, uint8_t color)
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{
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uint16_t c16 = c;
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uint16_t color16 = color;
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return c16 | color16 << 8;
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}
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// Initialize a VGA term
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void term_init(struct vgastate *state)
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{
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state->term_row = state->term_col = 0;
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state->term_color = make_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK);
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state->term_buf = (uint16_t *) VGA_BUF;
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for (size_t y = 0; y < VGA_HEIGHT; y++) {
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for (size_t x = 0; x < VGA_WIDTH; x++) {
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const size_t index = y * VGA_WIDTH + x;
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state->term_buf[index] = make_vgaEntry(' ', state->term_color);
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}
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}
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}
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// Write a character to a VGA term
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void term_putChar(struct vgastate *state, char c)
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{
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if (c == '\n')
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state->term_col = VGA_WIDTH - 1;
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else
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term_putEntryAt(state, c, state->term_color, state->term_col, state->term_row);
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if (++state->term_col == VGA_WIDTH) {
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state->term_col = 0;
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if (++state->term_row == VGA_HEIGHT) {
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state->term_row--;
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term_scroll(state);
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}
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}
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}
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// Place a character in a VGA term's buffer
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void term_putEntryAt(struct vgastate *state, char c, uint8_t color, size_t x, size_t y)
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{
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const size_t index = y * VGA_WIDTH + x;
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state->term_buf[index] = make_vgaEntry(c, color);
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}
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// Scroll the term down 1 line
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void term_scroll(struct vgastate *state)
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{
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// Move each row up
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for (size_t y = 1; y < VGA_HEIGHT; y++) {
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for (size_t x = 0; x < VGA_WIDTH; x++) {
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const size_t index = y * VGA_WIDTH + x;
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const size_t indexBelow = (y - 1) * VGA_WIDTH + x;
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state->term_buf[indexBelow] = state->term_buf[index];
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}
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}
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// Clear the last line
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for (size_t x = 0; x < VGA_WIDTH; x++) {
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const size_t index = (VGA_HEIGHT - 1) * VGA_WIDTH + x;
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state->term_buf[index] = ' ';
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}
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}
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// Set VGA term color
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void term_setColor(struct vgastate *state, uint8_t color)
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{
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state->term_color = color;
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}
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// Write a string to a VGA term
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void term_writeStr(struct vgastate *state, const char *data)
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{
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size_t dataLen = strlen(data);
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for (size_t i = 0; i < dataLen; i++)
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term_putChar(state, data[i]);
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}
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