Advertisement
Not a member of Pastebin yet?
Sign Up,
it unlocks many cool features!
- // Implementation of cprintf console output for user environments,
- // based on printfmt() and the sys_cputs() system call.
- //
- // cprintf is a debugging statement, not a generic output statement.
- // It is very important that it always go to the console, especially when
- // debugging file descriptor code!
- #include <inc/types.h>
- #include <inc/stdio.h>
- #include <inc/stdarg.h>
- #include <inc/lib.h>
- // Collect up to 256 characters into a buffer
- // and perform ONE system call to print all of them,
- // in order to make the lines output to the console atomic
- // and prevent interrupts from causing context switches
- // in the middle of a console output line and such.
- struct printbuf {
- int idx; // current buffer index
- int cnt; // total bytes printed so far
- char buf[256];
- };
- static void
- putch(int ch, struct printbuf *b)
- {
- b->buf[b->idx++] = ch;
- if (b->idx == 256-1) {
- sys_cputs(b->buf, b->idx);
- b->idx = 0;
- }
- b->cnt++;
- }
- int
- vcprintf(const char *fmt, va_list ap)
- {
- struct printbuf b;
- b.idx = 0;
- b.cnt = 0;
- vprintfmt((void*)putch, &b, fmt, ap);
- sys_cputs(b.buf, b.idx);
- return b.cnt;
- }
- int
- cprintf(const char *fmt, ...)
- {
- va_list ap;
- int cnt;
- va_start(ap, fmt);
- cnt = vcprintf(fmt, ap);
- va_end(ap);
- return cnt;
- }
Advertisement
Add Comment
Please, Sign In to add comment
Advertisement