68 lines
1.4 KiB
C
68 lines
1.4 KiB
C
#include "vga.h"
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static const size_t VGA_WIDTH = 80;
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static const size_t VGA_HEIGHT = 25;
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static size_t terminal_row;
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static size_t terminal_column;
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static uint8_t terminal_color;
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/* Note the use of the volatile keyword to prevent the compiler from eliminating dead stores. */
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static volatile uint16_t *terminal_buffer;
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uint8_t vga_entry_color(enum vga_color fg, enum vga_color bg);
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uint16_t vga_entry(unsigned char uc, uint8_t color);
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static size_t
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strlen(const char *str)
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{
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size_t len = 0;
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while (str[len++])
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;
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return len;
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}
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void
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terminal_initialize(size_t startrow)
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{
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terminal_row = startrow;
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terminal_column = 0;
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terminal_color = vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK);
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terminal_buffer = (uint16_t *)0xB8000;
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}
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void
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terminal_setcolor(uint8_t color)
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{
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terminal_color = color;
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}
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void
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terminal_putentryat(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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terminal_buffer[index] = vga_entry(c, color);
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}
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void
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terminal_putchar(char c)
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{
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terminal_putentryat(c, terminal_color, terminal_column, terminal_row);
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if (++terminal_column == VGA_WIDTH) {
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terminal_column = 0;
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if (++terminal_row == VGA_HEIGHT) terminal_row = 0;
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}
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}
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void
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terminal_write(const char *data, size_t size)
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{
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for (size_t i = 0; i < size; i++) terminal_putchar(data[i]);
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}
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void
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terminal_writestring(const char *data)
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{
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terminal_write(data, strlen(data));
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}
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