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Implement an optimization for INTREN/INTRDIS that bde pointed out last

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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]
This commit is contained in:
Peter Wemm 2001-01-15 04:18:58 +00:00
parent 10185bdc57
commit 194b08ffc3
3 changed files with 42 additions and 0 deletions
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14
sys/amd64/isa/icu_ipl.S
View File

@ -55,19 +55,33 @@ _imen: .long HWI_MASK
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

14
sys/amd64/isa/icu_ipl.s
View File

@ -55,19 +55,33 @@ _imen: .long HWI_MASK
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

14
sys/i386/isa/icu_ipl.s
View File

@ -55,19 +55,33 @@ _imen: .long HWI_MASK
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