From df899527e67c6c02fd317eeae25a9e7d7f6b3e8a Mon Sep 17 00:00:00 2001 From: Freya Murphy Date: Sat, 19 Apr 2025 16:36:51 -0400 Subject: UEFI and republicans --- kernel/drivers/gpu/vga_text.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) create mode 100644 kernel/drivers/gpu/vga_text.c (limited to 'kernel/drivers/gpu/vga_text.c') diff --git a/kernel/drivers/gpu/vga_text.c b/kernel/drivers/gpu/vga_text.c new file mode 100644 index 0000000..e3359c3 --- /dev/null +++ b/kernel/drivers/gpu/vga_text.c @@ -0,0 +1,27 @@ +#include +#include +#include +#include +#include + +#define VGA_ADDR 0xB8000 +#define VGA_WIDTH 80 +#define VGA_HEIGHT 25 +static volatile uint16_t *buffer = (uint16_t *)VGA_ADDR; + +// color +static uint8_t fg = 15, bg = 0; + +void vga_text_draw_char(char c, uint16_t x, uint16_t y) +{ + // output character + const size_t index = y * VGA_WIDTH + x; + buffer[index] = c | bg << 12 | fg << 8; + + // set cursor position on screen + const uint16_t pos = y * VGA_HEIGHT + x; + outb(0x3D4, 0x0F); + outb(0x3D5, (uint8_t)(pos & 0xFF)); + outb(0x3D4, 0x0E); + outb(0x3D5, (uint8_t)((pos >> 8) & 0xFF)); +} -- cgit v1.2.3-freya