From 912d2e3c7eb1baa71dda2c0a28aa5809eaa96f27 Mon Sep 17 00:00:00 2001 From: dzwdz Date: Sat, 16 Jul 2022 13:33:00 +0200 Subject: amd64: barely boot into kernel code --- src/kernel/arch/amd64/tty/vga.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 src/kernel/arch/amd64/tty/vga.c (limited to 'src/kernel/arch/amd64/tty/vga.c') diff --git a/src/kernel/arch/amd64/tty/vga.c b/src/kernel/arch/amd64/tty/vga.c new file mode 100644 index 0000000..e5f2274 --- /dev/null +++ b/src/kernel/arch/amd64/tty/vga.c @@ -0,0 +1,33 @@ +#include + +struct vga_cell { + unsigned char c; + unsigned char style; +} __attribute__((__packed__)); + +static const size_t vga_len = 80 * 25; +static struct vga_cell *vga = (void*) 0xB8000; +static size_t vga_pos = 0; + +static void vga_scroll(void) { + for (size_t i = 0; i < vga_len - 80; i++) + vga[i] = vga[i + 80]; + vga_pos -= 80; +} + +static void vga_putchar(char c) { + if (vga_pos >= vga_len - 80) + vga_scroll(); + vga[vga_pos++].c = c; +} + +void vga_write(const char *buf, size_t len) { + for (size_t i = 0; i < len; i++) + vga_putchar(buf[i]); +} + +void vga_clear(void) { + for (size_t i = 0; i < vga_len; i++) + vga[i].c = ' '; + vga_pos = 0; +} -- cgit v1.2.3