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GC i8254_microtime.

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This commit is contained in:
joerg 2008-01-22 12:41:38 +00:00
parent da1555e6a7
commit 2e737299d6
2 changed files with 1 additions and 108 deletions
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106
sys/arch/amd64/amd64/microtime.S
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@ -1,106 +0,0 @@
/* $NetBSD: microtime.S,v 1.3 2005/12/11 12:16:21 christos Exp $ */
/*-
* Copyright (c) 1993 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <machine/asm.h>
#include <dev/isa/isareg.h>
#include <dev/ic/i8253reg.h>
#include "assym.h"
#define IRQ_BIT(irq_num) (1 << ((irq_num) & 7))
#define IRQ_BYTE(irq_num) ((irq_num) >> 3)
ENTRY(i8254_microtime)
# clear registers and do whatever we can up front
xorl %edx,%edx
movl $(TIMER_SEL0|TIMER_LATCH),%eax
cli # disable interrupts
# select timer 0 and latch its counter
outb %al,$IO_TIMER1+TIMER_MODE
inb $IO_ICU1,%al # as close to timer latch as possible
movb %al,%ch # %ch is current ICU mask
# Read counter value into [%al %dl], LSB first
inb $IO_TIMER1+TIMER_CNTR0,%al
movb %al,%dl # %dl has LSB
inb $IO_TIMER1+TIMER_CNTR0,%al # %al has MSB
# save state of IIR in ICU, and of ipending, for later perusal
movb CPUVAR(IPENDING) + IRQ_BYTE(0),%cl
# save the current value of _time
movq _C_LABEL(time)(%rip),%r8 # get time.tv_sec
movq (_C_LABEL(time)+8)(%rip),%r9 # and time.tv_usec
sti # enable interrupts, we're done
# At this point we've collected all the state we need to
# compute the time. First figure out if we've got a pending
# interrupt. If the IRQ0 bit is set in ipending we've taken
# a clock interrupt without incrementing time, so we bump
# time.tv_usec by a tick. Otherwise if the ICU shows a pending
# interrupt for IRQ0 we (or the caller) may have blocked an interrupt
# with the cli. If the counter is not a very small value (3 as
# a heuristic), i.e. in pre-interrupt state, we add a tick to
# time.tv_usec
testb $IRQ_BIT(0),%cl # pending interrupt?
jnz 1f # yes, increment count
testb $IRQ_BIT(0),%ch # hardware interrupt pending?
jz 2f # no, continue
testb %al,%al # MSB zero?
jnz 1f # no, add a tick
cmpb $3,%dl # is this small number?
jbe 2f # yes, continue
1: addq _C_LABEL(isa_timer_tick)(%rip),%r9 # add a tick
# We've corrected for pending interrupts. Now do a table lookup
# based on each of the high and low order counter bytes to increment
# time.tv_usec
2: leaq _C_LABEL(isa_timer_msb_table)(%rip),%rsi
movw (%rsi,%rax,2),%ax
subw (%rsi,%rdx,2),%ax
addq %rax,%r9 # add msb increment
# Normalize the struct timeval. We know the previous increments
# will be less than a second, so we'll only need to adjust accordingly
cmpq $1000000,%r9 # carry in timeval?
jb 3f
subq $1000000,%r9 # adjust usec
incq %r8 # bump sec
3: movq %r8,(%rdi) # tvp->tv_sec = sec
movq %r9,8(%rdi) # tvp->tv_usec = usec
ret

3
sys/arch/amd64/include/cpu.h
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@ -1,4 +1,4 @@
/* $NetBSD: cpu.h,v 1.43 2008/01/05 21:52:02 yamt Exp $ */
/* $NetBSD: cpu.h,v 1.44 2008/01/22 12:41:38 joerg Exp $ */
/*-
* Copyright (c) 1990 The Regents of the University of California.
@ -336,7 +336,6 @@ void xen_initclocks(void);
void initrtclock(u_long);
void startrtclock(void);
void i8254_delay(unsigned int);
void i8254_microtime(struct timeval *);
void i8254_initclocks(void);
#endif