Save %fs and %gs across process switches. Leave some registers on the kernel
stack rather than in the PCB. Make savectx() do the stack copy.
This commit is contained in:
mycroft
parent
8fd9eafe10
commit
1ccad96544
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@ -35,7 +35,7 @@
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* SUCH DAMAGE.
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*
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* from: @(#)locore.s 7.3 (Berkeley) 5/13/91
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* $Id: locore.s,v 1.49 1994/04/04 03:47:20 mycroft Exp $
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* $Id: locore.s,v 1.50 1994/04/04 08:57:54 mycroft Exp $
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*/
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@ -1396,6 +1396,10 @@ badsw:
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*/
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SUPERALIGN_TEXT /* so profiling doesn't lump Idle with cpu_swtch */
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ENTRY(swtch)
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pushl %ebx
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pushl %esi
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pushl %edi
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incl _cnt+V_SWTCH
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/* switch to new process. first, save context as needed */
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@ -1405,36 +1409,33 @@ ENTRY(swtch)
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testl %ecx,%ecx
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jz sw0
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movl P_ADDR(%ecx),%ecx
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movl P_ADDR(%ecx),%esi
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movl (%esp),%eax # Hardware registers
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movl %eax,PCB_EIP(%ecx)
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movl %ebx,PCB_EBX(%ecx)
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movl %esp,PCB_ESP(%ecx)
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movl %ebp,PCB_EBP(%ecx)
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movl %esi,PCB_ESI(%ecx)
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movl %edi,PCB_EDI(%ecx)
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movl %esp,PCB_ESP(%esi)
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movl %ebp,PCB_EBP(%esi)
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movl %fs,%ax
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movl %eax,PCB_FS(%esi)
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movl %gs,%ax
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movl %eax,PCB_GS(%esi)
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movl _cpl,%eax
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movl %eax,PCB_IML(%esi)
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#if NNPX > 0
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/* have we used fp, and need a save? */
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mov _curproc,%eax
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cmp %eax,_npxproc
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movl _curproc,%edi
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cmpl %edi,_npxproc
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jne 1f
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pushl %ecx /* h/w bugs make saving complicated */
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leal PCB_SAVEFPU(%ecx),%eax
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pushl %eax
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leal PCB_SAVEFPU(%esi),%ebx
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pushl %ebx
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call _npxsave /* do it in a big C function */
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popl %eax
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popl %ecx
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addl $4,%esp
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1:
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#endif
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movl $0,_curproc # out of process
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movl _cpl,%eax # splhigh()
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movl $-1,_cpl
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movl %eax,PCB_IML(%ecx) # save ipl
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sw0: cli # splhigh doesn't do a cli
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movl _whichqs,%edi
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@ -1453,7 +1454,7 @@ sw1: bsfl %edi,%ebx # find a full q
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movl P_RLINK(%ecx),%eax
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movl %eax,P_RLINK(%edx)
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cmpl P_LINK(%ecx),%esi # q empty
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cmpl %edx,%esi # q empty
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jne 3f
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btrl %ebx,%edi # yes, clear to indicate empty
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@ -1477,19 +1478,18 @@ sw1: bsfl %edi,%ebx # find a full q
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movl %ebx,%cr3
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/* restore context */
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movl PCB_EBX(%edx),%ebx
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movl PCB_ESP(%edx),%esp
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movl PCB_EBP(%edx),%ebp
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movl PCB_ESI(%edx),%esi
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movl PCB_EDI(%edx),%edi
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movl PCB_EIP(%edx),%eax
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movl %eax,(%esp)
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movl PCB_FS(%edx),%eax
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movl %ax,%fs
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movl PCB_GS(%edx),%eax
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movl %ax,%gs
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movl %ecx,_curproc # into next process
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movl %edx,_curpcb
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#ifdef USER_LDT
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cmpl $0, PCB_USERLDT(%edx)
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cmpl $0,PCB_USERLDT(%edx)
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jnz 1f
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movl __default_ldt,%eax
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cmpl _currentldt,%eax
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@ -1509,10 +1509,9 @@ sw1: bsfl %edi,%ebx # find a full q
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addl $4,%esp
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movl %edx,%eax # return (p);
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ret
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ENTRY(mvesp)
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movl %esp,%eax
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popl %edi
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popl %esi
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popl %ebx
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ret
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/*
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@ -1539,16 +1538,21 @@ ENTRY(swtch_to_inactive)
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* for alternate return ala longjmp in swtch if altreturn is true.
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*/
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ENTRY(savectx)
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movl 4(%esp),%ecx
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pushl %ebx
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pushl %esi
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pushl %edi
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movl 16(%esp),%esi /* esi = p2->p_addr */
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movl %esp,PCB_ESP(%esi)
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movl %ebp,PCB_EBP(%esi)
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movl %fs,%ax
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movl %eax,PCB_FS(%esi)
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movl %gs,%ax
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movl %eax,PCB_GS(%esi)
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movl _cpl,%eax
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movl %eax,PCB_IML(%ecx)
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movl (%esp),%eax
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movl %eax,PCB_EIP(%ecx)
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movl %ebx,PCB_EBX(%ecx)
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movl %esp,PCB_ESP(%ecx)
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movl %ebp,PCB_EBP(%ecx)
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movl %esi,PCB_ESI(%ecx)
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movl %edi,PCB_EDI(%ecx)
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movl %eax,PCB_IML(%esi)
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#if NNPX > 0
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/*
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@ -1563,48 +1567,43 @@ ENTRY(savectx)
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* have to handle h/w bugs for reloading. We used to lose the
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* parent's npx state for forks by forgetting to reload.
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*/
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movl _npxproc,%eax
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testl %eax,%eax
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jz 1f
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movl _curproc,%edi /* edi = p1 */
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cmpl %edi,_npxproc
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jne 1f
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pushl %ecx
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movl P_ADDR(%eax),%eax
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leal PCB_SAVEFPU(%eax),%eax
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pushl %eax
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pushl %eax
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leal PCB_SAVEFPU(%esi),%ebx /* ebx = esi->u_pcb.pcb_savefpu */
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pushl %ebx
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call _npxsave
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addl $4,%esp
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popl %eax
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popl %ecx
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pushl %ecx
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pushl $108+8*2 /* XXX h/w state size + padding */
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leal PCB_SAVEFPU(%ecx),%ecx
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pushl %ecx
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pushl %eax
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pushl $108+8*2 /* XXX h/w state size + padding */
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movl P_ADDR(%edi),%edi /* edi = p1->p_addr */
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leal PCB_SAVEFPU(%edi),%edi /* edi = edi->u_pcb.pcb_savefpu */
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pushl %edi
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pushl %ebx
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call _bcopy
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addl $12,%esp
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popl %ecx
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1:
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#endif
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cmpl $0,8(%esp)
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cmpl $0,20(%esp)
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je 1f
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movl %esp,%edx # relocate current sp relative to pcb
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subl $(_kstack),%edx # (sp is relative to kstack):
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addl %edx,%ecx # pcb += sp - kstack;
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movl %eax,(%ecx) # write return pc at (relocated) sp@
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# this mess deals with replicating register state gcc hides
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movl 12(%esp),%eax
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movl %eax,12(%ecx)
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movl 16(%esp),%eax
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movl %eax,16(%ecx)
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movl 20(%esp),%eax
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movl %eax,20(%ecx)
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movl 24(%esp),%eax
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movl %eax,24(%ecx)
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1:
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xorl %eax,%eax # return 0
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movl %esp,%eax # eax = stack pointer
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movl %eax,%edx # edx = stack offset from bottom
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subl $_kstack,%edx
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movl $(UPAGES << PGSHIFT),%ecx # ecx = ctob(UPAGES) - offset
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subl %edx,%ecx
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pushl %ecx
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addl %edx,%esi # esi = stack in p2
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pushl %esi
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pushl %eax
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call _bcopy
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addl $12,%esp
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1: xorl %eax,%eax # return 0
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popl %edi
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popl %esi
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popl %ebx
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ret
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/*
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