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Another tiny optimization.

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This commit is contained in:
mycroft 1994-09-08 21:56:14 +00:00
parent a90cca9558
commit 289bc175c6
1 changed files with 8 additions and 11 deletions
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19
sys/arch/i386/i386/locore.s
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@ -37,7 +37,7 @@
* SUCH DAMAGE.
*
* from: @(#)locore.s 7.3 (Berkeley) 5/13/91
* $Id: locore.s,v 1.81 1994/09/07 20:32:00 mycroft Exp $
* $Id: locore.s,v 1.82 1994/09/08 21:56:14 mycroft Exp $
*/
/*
@ -1468,11 +1468,11 @@ ENTRY(setrunqueue)
shrl $2,%edx
btsl %edx,_whichqs # set q full bit
leal _qs(,%edx,8),%edx # locate q hdr
movl %edx,P_FORW(%eax) # link process on tail of q
movl P_BACK(%edx),%ecx
movl %edx,P_FORW(%eax) # link process on tail of q
movl %eax,P_BACK(%edx)
movl %ecx,P_BACK(%eax)
movl %eax,P_FORW(%ecx)
movl %ecx,P_BACK(%eax)
ret
#ifdef DIAGNOSTIC
1: pushl $2f
@ -1496,9 +1496,9 @@ ENTRY(remrq)
#endif /* DIAGNOSTIC */
movl P_FORW(%esi),%ecx # unlink process
movl P_BACK(%esi),%edx
movl %edx,P_BACK(%ecx)
movl %ecx,P_FORW(%edx)
movl $0,P_BACK(%esi) # zap reverse link to indicate off list
movl %edx,P_BACK(%ecx)
movl $0,P_BACK(%esi) # zap reverse link to indicate off list
cmpl %edx,%ecx # q still has something?
jne 2f
btrl %eax,_whichqs # no; clear bit
@ -1576,22 +1576,19 @@ sw1: bsfl %ecx,%ebx # find a full q
movl P_FORW(%eax),%edi # unlink from front of process q
#ifdef DIAGNOSTIC
cmpl %edi,%eax # linked to self (e.g. nothing queued)?
cmpl %edi,%eax # linked to self (i.e. nothing queued)?
je _switch_error # not possible
#endif /* DIAGNOSTIC */
movl P_FORW(%edi),%edx
movl %edx,P_FORW(%eax)
movl %eax,P_BACK(%edx)
cmpl %edx,%eax # q empty
jne 3f
btrl %ebx,%ecx # yes, clear to indicate empty
3: movl P_BACK(%edi),%eax
movl %eax,P_BACK(%edx)
movl %ecx,_whichqs # update q status
/* We just did it. */
3: /* We just did it. */
xorl %eax,%eax
movl %eax,_want_resched