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/* -*- c++ -*- */
/*
* Copyright 2003 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* GNU Radio is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3, or (at your option)
* any later version.
*
* GNU Radio is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU Radio; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
/*
* Delay approximately 1 microsecond (including overhead in udelay).
*/
static void
udelay1 (void) _naked
{
_asm ; lcall that got us here took 4 bus cycles
ret ; 4 bus cycles
_endasm;
}
/*
* delay for approximately usecs microseconds
*/
void
udelay (unsigned char usecs)
{
do {
udelay1 ();
} while (--usecs != 0);
}
/*
* Delay approximately 1 millisecond.
* We're running at 48 MHz, so we need 48,000 clock cycles.
*
* Note however, that each bus cycle takes 4 clock cycles (not obvious,
* but explains the factor of 4 problem below).
*/
static void
mdelay1 (void) _naked
{
_asm
mov dptr,#(-1200 & 0xffff)
002$:
inc dptr ; 3 bus cycles
mov a, dpl ; 2 bus cycles
orl a, dph ; 2 bus cycles
jnz 002$ ; 3 bus cycles
ret
_endasm;
}
void
mdelay (unsigned int msecs)
{
do {
mdelay1 ();
} while (--msecs != 0);
}
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