freebsd-dev/sys/i386/isa/icu_ipl.s
peter 95938d30bd Implement an optimization for INTREN/INTRDIS that bde pointed out last
time I tinkered around here.  Since INTREN is called from the interrupt
critical path now, it should not be too expensive.  In this case, we
look at the bits being changed to decide which 8 bit IO port to write to
rather than unconditionally writing to both.  I could probably have gone
further and only done the write if the bits actually changed, but that
seemed overkill for the usual case in interrupt threads.

[an outb is rather expensive when it has to cross the ISA bus]
2001-01-15 04:18:58 +00:00

88 lines
2.6 KiB
ArmAsm

/*-
* Copyright (c) 1989, 1990 William F. Jolitz.
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* William Jolitz.
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*
* $FreeBSD$
*/
.data
ALIGN_DATA
/* interrupt mask enable (all h/w off) */
.globl _imen
_imen: .long HWI_MASK
.text
SUPERALIGN_TEXT
#ifdef PC98
#define MASK_OFFSET 2
#else
#define MASK_OFFSET 1
#endif
ENTRY(INTREN)
movl 4(%esp), %eax
movl %eax, %ecx
notl %eax
andl %eax, imen
movl imen, %eax
testb %cl, %cl
je 1f
outb %al, $(IO_ICU1 + MASK_OFFSET)
1:
testb %ch, %ch
je 2f
shrl $8, %eax
outb %al, $(IO_ICU2 + MASK_OFFSET)
2:
ret
ENTRY(INTRDIS)
movl 4(%esp), %eax
movl %eax, %ecx
orl %eax, imen
movl imen, %eax
testb %cl, %cl
je 1f
outb %al, $(IO_ICU1 + MASK_OFFSET)
1:
testb %ch, %ch
je 2f
shrl $8, %eax
outb %al, $(IO_ICU2 + MASK_OFFSET)
2:
ret