void pgdown()
{
curbp->b_page = curbp->b_point = upup(curbp, curbp->b_epage);
while (0 < curbp->b_row--)
down();
curbp->b_epage = pos(curbp, curbp->b_ebuf);
}
void pgup()
{
int i = curwp->w_rows;
while (0 < --i) {
curbp->b_page = upup(curbp, curbp->b_page);
up();
}
}
void forward_page()
{
curbp->b_page = curbp->b_point = upup(curbp, curbp->b_epage);
while (0 < curbp->b_row--)
down();
/* this stops a reframe in display(), and epage is recalculated during display() */
curbp->b_epage = pos(curbp, curbp->b_ebuf);
}
void up()
{
curbp->b_point = lncolumn(curbp, upup(curbp, curbp->b_point),curbp->b_col);
}
