Reverse some VM functions (Daniel)

VeryPopularFunction (now GetPARPageInfo) takes a page number in the PAR
and returns a bunch of info on it. The flags of the PTE are copied into
cr5-cr7 of the condition register so that VMCalls can easily make
decisions off of them. I had already figured out the bit flags of the
PTEs Mac OS 9 uses when I reversed PagingFunc1. The definitions are in
the end of the 'Area Definitions.txt' file I sent you a while ago.

If you see a  ' bltl cr5, VMDoSomethingWithTLB' (now RemovePageFromTLB)
followed by a ' bltl cr5, major_0x09b40' (now RemovePTEFromHTAB), you
know that the function is manipulating pages directly. RemovePageFromTLB
clears a page from the TLB if it follows a VeryPopularFunction call.
RemovePTEFromHTAB takes a page that is resident in the HTAB and removes
its HTAB entry. cr5_lt is bit 20 (mask 0x800), which my notes tell me is
set when the PTE is in the HTAB. Altogether, the sequence translates to
'if the page is in the HTAB, flush it from the TLB and delete its HTAB
entry'. VMExchangePages uses this (twice) to make sure there are no race
conditions when it is swapping the data in the pages.

I still don't have proof, but I am very very strongly convinced that
KDP.FlatPageListPointer is always equal to the PAR's PageMapArrayPtr.

On an unrelated note, KCMapPage seems to always panic when called on an
area where the PageMapArrayPtr is 2d. I have absolutely no idea why this
happens, but it is bad news for MPMapper because the threshold for
2-dimensionality is around 1 MB. I would have to make 512 separate
CreateArea calls to map all the memory without the NK panicking. I will
have to look into this.

NanoKernel/NKMPCalls.s

@@ -724,17 +724,17 @@ MPCall_0	;	OUTSIDE REFERER
 
 	_Lock			PSA.HTABLock, scratch1=r17, scratch2=r18
 
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
 	bge-	cr4, MPCall_0_0xd8
 	bgt-	cr5, MPCall_0_0xd8
 	bns-	cr7, MPCall_0_0xd8
 	bgt-	cr7, MPCall_0_0xd8
-	bltl+	cr5, VMDoSomethingWithTLB
+	bltl+	cr5, RemovePageFromTLB
 	bgel+	cr5, VMSecondLastExportedFunc
 	ori		r16, r16,  0x404
 	li		r31,  0x03
 	rlwimi	r9, r31,  0, 30, 31
-	bl		VMDoSomeIO
+	bl		EditPTEInHTAB
 	mr		r7, r30
 	mr		r6, r29
 	_AssertAndRelease	PSA.HTABLock, scratch=r16

NanoKernel/NKVMCalls.s

@@ -164,7 +164,7 @@ VMDispatchTableEnd
 ;	setPTEntryGivenPage
 ;	VMShouldClean
 ;	VMAllocateMemory
-;	VeryPopularFunction
+;	GetPARPageInfo
 ;	major_0x09c9c
 
 VMReturnMinus1	;	OUTSIDE REFERER
@@ -231,13 +231,13 @@ VMFinalInit	;	OUTSIDE REFERER
 @loop
 	srwi	r4, r31, 12
 	lwz		r9, KDP.PrimaryAddrRangePages(r1)
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
 	bge-	cr4, @skip
-	bltl-	cr5, VMDoSomethingWithTLB
+	bltl-	cr5, RemovePageFromTLB
 	bgel-	cr5, VMSecondLastExportedFunc
 	ori		r16, r16,  0x400
 	rlwimi	r9, r29,  0,  0, 19
-	bl		major_0x09b40
+	bl		RemovePTEFromHTAB
 	addi	r31, r31,  0x1000
 	cmplw	r31, r30
 	ble+	@loop
@@ -315,8 +315,8 @@ VMInit_0xa8
 	rlwimi	r3, r8, 21, 12, 15
 	cmpw	r3, r4
 	bnel+	Local_Panic
-	bl		VMDoSomethingWithTLB
+	bl		RemovePageFromTLB
-	bl		major_0x09b40
+	bl		RemovePTEFromHTAB
 
 VMInit_0x100
 	cmpwi	r7,  0x00
@@ -514,26 +514,26 @@ VMInit_Fail
 	DeclareVMCallWithAlt	12, VMExchangePages, VMReturnNotReady
 
 VMExchangePages	;	OUTSIDE REFERER
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
 	bge+	cr4, VMReturnMinus1
 	bgt+	cr5, VMReturnMinus1
 	bns+	cr7, VMReturnMinus1
 	bgt+	cr6, VMReturnMinus1
 	bne+	cr6, VMReturnMinus1
-	bltl-	cr5, VMDoSomethingWithTLB
+	bltl-	cr5, RemovePageFromTLB
-	bltl-	cr5, major_0x09b40
+	bltl-	cr5, RemovePTEFromHTAB
 	mr		r6, r15
 	mr		r4, r5
 	mr		r5, r16
 	lwz		r9, KDP.PrimaryAddrRangePages(r1)
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
 	bge+	cr4, VMReturnMinus1
 	bgt+	cr5, VMReturnMinus1
 	bns+	cr7, VMReturnMinus1
 	bgt+	cr6, VMReturnMinus1
 	bne+	cr6, VMReturnMinus1
-	bltl-	cr5, VMDoSomethingWithTLB
+	bltl-	cr5, RemovePageFromTLB
-	bltl-	cr5, major_0x09b40
+	bltl-	cr5, RemovePTEFromHTAB
 	stw		r5,  0x0000(r15)
 	stw		r16,  0x0000(r6)
 	rlwinm	r4, r5,  0,  0, 19
@@ -578,7 +578,7 @@ VMGetPhysicalPage_0x28
 	lwz		r9, KDP.PrimaryAddrRangePages(r1)
 
 VMGetPhysicalPage_0x30
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
 	bns+	cr7, VMReturnMinus1
 	srwi	r3, r9, 12
 	b		VMReturn
@@ -621,13 +621,13 @@ getPTEntryGivenPage_0x48
 	lwz		r9, KDP.PrimaryAddrRangePages(r1)
 
 getPTEntryGivenPage_0x50
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
 	mr		r3, r16
 	bns-	cr7, getPTEntryGivenPage_0x74
 	rlwimi	r3, r9,  0,  0, 19
 	bge-	cr5, getPTEntryGivenPage_0x74
-	bl		VMDoSomethingWithTLB
+	bl		RemovePageFromTLB
-	bl		VMDoSomeIO_0x4
+	bl		EditPTEOnlyInHTAB
 	mr		r3, r16
 	rlwimi	r3, r9,  0,  0, 19
 
@@ -713,7 +713,7 @@ major_0x08d88_0xb0	;	OUTSIDE REFERER
 	DeclareVMCallWithAlt	5, VMIsInited, VMReturnNotReady
 
 VMIsInited	;	OUTSIDE REFERER
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
 	bso+	cr7, VMReturn1
 	rlwinm	r3, r16, 16, 31, 31
 	b		VMReturn
@@ -746,7 +746,7 @@ VMIsResident_0x28
 	lwz		r9, KDP.PrimaryAddrRangePages(r1)
 
 VMIsResident_0x30
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
 	clrlwi	r3, r16,  0x1f
 	b		VMReturn
 
@@ -757,12 +757,12 @@ VMIsResident_0x30
 	DeclareVMCallWithAlt	4, VMIsUnmodified, VMReturnNotReady
 
 VMIsUnmodified	;	OUTSIDE REFERER
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
 	rlwinm	r3, r16, 28, 31, 31
 	xori	r3, r3,  0x01
 	bge+	cr5, VMReturn
-	bl		VMDoSomethingWithTLB
+	bl		RemovePageFromTLB
-	bl		VMDoSomeIO_0x4
+	bl		EditPTEOnlyInHTAB
 	rlwinm	r3, r16, 28, 31, 31
 	xori	r3, r3,  0x01
 	b		VMReturn
@@ -792,9 +792,9 @@ VMLRU_0x1c
 	bge-	cr5, VMLRU_0x50
 	add		r14, r14, r7
 	lwz		r8,  0x0000(r14)
-	bl		VMDoSomethingWithTLB
+	bl		RemovePageFromTLB
 	andc	r9, r9, r5
-	bl		major_0x09b40
+	bl		RemovePTEFromHTAB
 	subf	r14, r7, r14
 
 VMLRU_0x50
@@ -846,20 +846,20 @@ VMMakePageCacheable	;	OUTSIDE REFERER
 	bne-	cr1, VMMakePageCacheable_0x4
 
 VMMakePageCacheable_0x4
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
 	rlwinm	r7, r16,  0, 25, 26
 	cmpwi	r7,  0x20
 	bns+	cr7, VMReturnMinus1
 	beq+	VMReturn
 	bge-	cr4, VMMakePageCacheable_0x40
-	bltl-	cr5, VMDoSomethingWithTLB
+	bltl-	cr5, RemovePageFromTLB
 	bgel-	cr5, VMSecondLastExportedFunc
 	rlwinm	r16, r16,  0, 27, 24
 	rlwinm	r9, r9,  0, 27, 24
 	lwz		r7, KDP.PageAttributeInit(r1)
 	rlwimi	r9, r7,  0, 27, 28
 	ori		r16, r16,  0x20
-	bl		VMDoSomeIO
+	bl		EditPTEInHTAB
 	b		VMReturn
 
 VMMakePageCacheable_0x40
@@ -922,19 +922,19 @@ VMMakePageWriteThrough	;	OUTSIDE REFERER
 	bne-	cr1, VMMakePageWriteThrough_0x4
 
 VMMakePageWriteThrough_0x4
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
 	rlwinm.	r7, r16,  0, 25, 26
 	bns+	cr7, VMReturnMinus1
 	beq+	VMReturn
 	bge-	cr4, VMMakePageWriteThrough_0x3c
-	bltl-	cr5, VMDoSomethingWithTLB
+	bltl-	cr5, RemovePageFromTLB
 	bgel-	cr5, VMSecondLastExportedFunc
 	rlwinm	r16, r16,  0, 27, 24
 	rlwinm	r9, r9,  0, 27, 24
 	lwz		r7, KDP.PageAttributeInit(r1)
 	rlwimi	r9, r7,  0, 27, 28
 	ori		r9, r9,  0x40
-	bl		VMDoSomeIO
+	bl		EditPTEInHTAB
 	b		VMMakePageNonCacheable_0x3c
 
 VMMakePageWriteThrough_0x3c
@@ -1056,10 +1056,10 @@ PageSetCommon_0xc4
 	addi	r14, r14,  0x08
 
 PageSetCommon_0xc8
-	bl		VMDoSomethingWithTLB
+	bl		RemovePageFromTLB
 	li		r8,  0x00
 	li		r9,  0x00
-	bl		VMDoSomeIO_0x4
+	bl		EditPTEOnlyInHTAB
 	b		VMReturn
 
 
@@ -1072,20 +1072,20 @@ VMMakePageNonCacheable	;	OUTSIDE REFERER
 	bne-	cr1, VMMakePageNonCacheable_0x4
 
 VMMakePageNonCacheable_0x4
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
 	rlwinm	r7, r16,  0, 25, 26
 	cmpwi	r7,  0x60
 	bns+	cr7, VMReturnMinus1
 	beq+	VMReturn
 	bge-	cr4, VMMakePageNonCacheable_0x78
-	bltl-	cr5, VMDoSomethingWithTLB
+	bltl-	cr5, RemovePageFromTLB
 	bgel-	cr5, VMSecondLastExportedFunc
 	rlwinm	r9, r9,  0, 27, 24
 	lwz		r7, KDP.PageAttributeInit(r1)
 	rlwimi	r9, r7,  0, 27, 28
 	ori		r16, r16,  0x60
 	ori		r9, r9,  0x20
-	bl		VMDoSomeIO
+	bl		EditPTEInHTAB
 
 VMMakePageNonCacheable_0x3c	;	OUTSIDE REFERER
 	rlwinm	r4, r9,  0,  0, 19
@@ -1200,11 +1200,11 @@ VMMarkBacking_0x50
 	lwz		r9, KDP.PrimaryAddrRangePages(r1)
 
 VMMarkBacking_0x58
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
 	bge+	cr4, VMReturnMinus1
 	bgt+	cr5, VMReturnMinus1
-	bltl-	cr5, VMDoSomethingWithTLB
+	bltl-	cr5, RemovePageFromTLB
-	bltl-	cr5, major_0x09b40
+	bltl-	cr5, RemovePTEFromHTAB
 	rlwimi	r16, r5, 16, 15, 15
 	li		r7,  0x01
 	andc	r16, r16, r7
@@ -1218,16 +1218,16 @@ VMMarkBacking_0x58
 	DeclareVMCallWithAlt	9, VMMarkCleanUnused, VMReturnNotReady
 
 VMMarkCleanUnused	;	OUTSIDE REFERER
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
 	bge+	cr4, VMReturnMinus1
 	bns+	cr7, VMReturnMinus1
-	bltl-	cr5, VMDoSomethingWithTLB
+	bltl-	cr5, RemovePageFromTLB
 	beq-	cr2, VMMarkCleanUnused_0x2c
 	bgel-	cr5, VMSecondLastExportedFunc
 	li		r7,  0x180
 	andc	r9, r9, r7
 	ori		r16, r16,  0x100
-	bl		VMDoSomeIO
+	bl		EditPTEInHTAB
 	b		VMReturn
 
 VMMarkCleanUnused_0x2c
@@ -1235,7 +1235,7 @@ VMMarkCleanUnused_0x2c
 	ori		r16, r16,  0x100
 	li		r7,  0x18
 	andc	r16, r16, r7
-	bl		major_0x09b40
+	bl		RemovePTEFromHTAB
 	b		VMReturn
 
 
@@ -1303,7 +1303,7 @@ VMMarkResident_0x50
 	lwz		r9, KDP.PrimaryAddrRangePages(r1)
 
 VMMarkResident_0x58
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
 	bge+	cr4, VMReturnMinus1
 	bso+	cr7, VMReturnMinus1
 	bltl+	cr5, Local_Panic
@@ -1311,7 +1311,7 @@ VMMarkResident_0x58
 	ori		r16, r16,  0x01
 	stw		r16,  0x0000(r15)
 	bl		VMSecondLastExportedFunc
-	bl		VMDoSomeIO
+	bl		EditPTEInHTAB
 	b		VMReturn
 
 
@@ -1325,7 +1325,7 @@ VMPTest	;	OUTSIDE REFERER
 	cmplw	r4, r9
 	li		r3,  0x4000
 	bge+	VMReturn
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
 	li		r3,  0x400
 	bns+	cr7, VMReturn
 	li		r3,  0x00
@@ -1381,7 +1381,7 @@ setPTEntryGivenPage_0x5c
 setPTEntryGivenPage_0x64
 	mr		r6, r4
 	mr		r4, r5
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
 	bge+	cr4, VMReturnMinus1
 	xor		r7, r16, r6
 	li		r3,  0x461
@@ -1392,19 +1392,19 @@ setPTEntryGivenPage_0x64
 	xor		r16, r16, r7
 	stw		r16,  0x0000(r15)
 	bge+	cr5, VMReturn
-	bl		VMDoSomethingWithTLB
+	bl		RemovePageFromTLB
 	lwz		r16,  0x0000(r15)
 	bne-	cr2, setPTEntryGivenPage_0xb4
 	andi.	r7, r16,  0x08
 	bne-	setPTEntryGivenPage_0xb4
-	bl		major_0x09b40
+	bl		RemovePTEFromHTAB
 	b		VMReturn
 
 setPTEntryGivenPage_0xb4
 	rlwimi	r9, r16,  5, 23, 23
 	rlwimi	r9, r16,  3, 24, 24
 	rlwimi	r9, r16, 30, 31, 31
-	bl		VMDoSomeIO_0x4
+	bl		EditPTEOnlyInHTAB
 	b		VMReturn
 
 
@@ -1414,10 +1414,10 @@ setPTEntryGivenPage_0xb4
 	DeclareVMCallWithAlt	6, VMShouldClean, VMReturnNotReady
 
 VMShouldClean	;	OUTSIDE REFERER
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
 	bns+	cr7, VMReturn0
 	bge+	cr4, VMReturnMinus1
-	bltl-	cr5, VMDoSomethingWithTLB
+	bltl-	cr5, RemovePageFromTLB
 	blt-	cr7, VMShouldClean_0x34
 	bns-	cr6, VMShouldClean_0x34
 	xori	r16, r16,  0x10
@@ -1425,11 +1425,11 @@ VMShouldClean	;	OUTSIDE REFERER
 	stw		r16,  0x0000(r15)
 	bge+	cr5, VMReturn1
 	xori	r9, r9,  0x80
-	bl		VMDoSomeIO_0x4
+	bl		EditPTEOnlyInHTAB
 	b		VMReturn1
 
 VMShouldClean_0x34
-	bltl-	cr5, VMDoSomeIO_0x4
+	bltl-	cr5, EditPTEOnlyInHTAB
 	b		VMReturn0
 
 
@@ -1473,9 +1473,9 @@ VMAllocateMemory_0x6c
 
 VMAllocateMemory_0x74
 	addi	r4, r4, -0x01
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
-	bltl-	cr5, VMDoSomethingWithTLB
+	bltl-	cr5, RemovePageFromTLB
-	bltl-	cr5, major_0x09b40
+	bltl-	cr5, RemovePTEFromHTAB
 	lwz		r9, KDP.PrimaryAddrRangePages(r1)
 	subf	r8, r4, r9
 	cmplw	cr7, r5, r8
@@ -1684,87 +1684,72 @@ VMAllocateMemory_0x360
 
 
 
-;	                  VeryPopularFunction                   
+;This function gets sent an page# for a page in the main mac os memory area and returns a bunch of useful info on it.
+;Return values that mention HTAB are undefined when the PTE is not in the HTAB
+;HTAB residence is determined by bit 20 (value 0x800) of the PTE. This is often checked by a bltl cr5
 
-;	Xrefs:
+;	ARG		page# r4, KDP.VMMaxVirtualPages r9,
-;	VMFinalInit
+;	RET		PTE_flags CR, HTAB_upper r8, HTAB_lower r9, PTE_value r16, HTAB_entry_loc r14, PTE_loc r15, 
-;	VMExchangePages
-;	VMGetPhysicalPage
-;	getPTEntryGivenPage
-;	VMIsInited
-;	VMIsResident
-;	VMIsUnmodified
-;	VMMakePageCacheable
-;	VMMakePageWriteThrough
-;	VMMakePageNonCacheable
-;	VMMarkBacking
-;	VMMarkCleanUnused
-;	VMMarkResident
-;	VMPTest
-;	setPTEntryGivenPage
-;	VMShouldClean
-;	VMAllocateMemory
-;	VMLastExportedFunc
-;	major_0x0b144
 
-VeryPopularFunction	;	OUTSIDE REFERER
+
-	cmplw	cr4, r4, r9
+GetPARPageInfo	;	OUTSIDE REFERER
+	cmplw	cr4, r4, r9	;r9 is VMMaxVirtualPages by convention
 	lwz		r15,  KDP.FlatPageListPtr(r1)
 	slwi	r8, r4,  2
-	bge-	cr4, VeryPopularFunction_0x40
+	bge-	cr4, GetPARPageInfo_0x40
 
-VeryPopularFunction_0x10
+GetPARPageInfo_0x10
-	lwzux	r16, r15, r8
+	lwzux	r16, r15, r8	;get PTE from KDP.FlatPageListPointer
-	lwz		r14, KDP.HTABORG(r1)
+	lwz		r14,  KDP.HTABORG(r1)
-	mtcrf	 0x07, r16
+	mtcrf	 0x07, r16	;copy bits 20-31 to cr
-	rlwinm	r8, r16, 23,  9, 28
+	rlwinm	r8, r16, 23,  9, 28;convert page# into an index
-	rlwinm	r9, r16,  0,  0, 19
+	rlwinm	r9, r16,  0,  0, 19;get unshifted page#
-	bgelr-	cr5
+	bgelr-	cr5		;return if PTE is not in HTAB
-	lwzux	r8, r14, r8
+	lwzux	r8, r14, r8	;get first word of PTE from HTAB
-	lwz		r9,  0x0004(r14)
+	lwz		r9,  0x0004(r14);get second word of PTE from HTAB
 	mtcrf	 0x80, r8
-	bns+	cr7, Local_Panic
+	bns+	cr7, Local_Panic;panic if the PTE is in the HTAB but isn't mapped to a real page
-	bltlr-	
+	bltlr-			;return if PTE is valid
-	bl		Local_Panic
+	bl		Local_Panic;panic if PTE isn't valid but is in the HTAB
 
-VeryPopularFunction_0x40
+GetPARPageInfo_0x40	;some kind of little-used code path for when VMMaxVirtualPages is invalid? ROM overlay?
-	lwz		r9, KDP.VMMaxVirtualPages(r1)
+	lwz		r9,  KDP.VMMaxVirtualPages(r1)
 	cmplw	cr4, r4, r9
 	rlwinm.	r9, r4,  0,  0, 11
-	blt+	cr4, VMReturnMinus1
+	blt+	cr4, VMReturnMinus1;return failure if r4<VMMaxVirtualPages
-	bne+	VMReturnMinus1
+	bne+	VMReturnMinus1	;return failure if bits 0-11 of r4 are non-zero
-	lwz		r15,  0x05e8(r1)
+	lwz		r15,  0x05e8(r1);this appears to be an array of 8-byte structures.
-	rlwinm	r9, r4, 19, 25, 28
+	rlwinm	r9, r4, 19, 25, 28;copy bits 12-15 or r4 to bits 25-28 of r9
-	lwzx	r15, r15, r9
+	lwzx	r15, r15, r9	;do an index for some reason
-	clrlwi	r9, r4,  0x10
+	clrlwi	r9, r4,  0x10	;copy bits 16-31 to r9
 	lhz		r8,  0x0000(r15)
-	b		VeryPopularFunction_0x70
+	b		GetPARPageInfo_0x70
 
-VeryPopularFunction_0x6c
+GetPARPageInfo_0x6c
 	lhzu	r8,  0x0008(r15)
 
-VeryPopularFunction_0x70
+GetPARPageInfo_0x70
 	lhz		r16,  0x0002(r15)
 	subf	r8, r8, r9
 	cmplw	cr4, r8, r16
-	bgt+	cr4, VeryPopularFunction_0x6c
+	bgt+	cr4, GetPARPageInfo_0x6c
 	lwz		r9,  0x0004(r15)
 	andi.	r16, r9,  0xc00
 	cmpwi	cr6, r16,  0x400
 	cmpwi	cr7, r16,  0xc00
-	beq-	VeryPopularFunction_0xac
+	beq-	GetPARPageInfo_0xac
-	beq-	cr6, VeryPopularFunction_0xb4
+	beq-	cr6, GetPARPageInfo_0xb4
 	bne+	cr7, VMReturnMinus1
 	slwi	r8, r8,  2
 	rlwinm	r15, r9, 22,  0, 29
 	crset	cr4_lt
-	b		VeryPopularFunction_0x10
+	b		GetPARPageInfo_0x10
 
-VeryPopularFunction_0xac
+GetPARPageInfo_0xac
 	slwi	r8, r8, 12
 	add		r9, r9, r8
 
-VeryPopularFunction_0xb4
+GetPARPageInfo_0xb4
 	rlwinm	r16, r9,  0,  0, 19
 	crclr	cr4_lt
 	rlwinm	r9, r9,  0, 22, 19
@@ -1780,40 +1765,24 @@ VeryPopularFunction_0xb4
 
 
 
-;	                  VMDoSomethingWithTLB                  
+;invalidates TLB entry for page?
-
+;registers are assumed to be unmodified after call to VeryPopularFunction
-;	Xrefs:
+;r4 is address
-;	VMFinalInit
+;r14 is address of HTAB entry
-;	VMInit
+;r8 is upper word of HTAB entry
-;	VMExchangePages
+RemovePageFromTLB	;	OUTSIDE REFERER
-;	getPTEntryGivenPage
-;	VMIsUnmodified
-;	VMLRU
-;	VMMakePageCacheable
-;	VMMakePageWriteThrough
-;	PageSetCommon
-;	VMMakePageNonCacheable
-;	VMMarkBacking
-;	VMMarkCleanUnused
-;	setPTEntryGivenPage
-;	VMShouldClean
-;	VMAllocateMemory
-;	VMLastExportedFunc
-;	major_0x0b144
-
-VMDoSomethingWithTLB	;	OUTSIDE REFERER
 	mfpvr	r9
-	clrlwi	r8, r8,  0x01
+	clrlwi	r8, r8,  0x01	;clear valid bit from upper word of HTAB entry
 	rlwinm.	r9, r9,  0,  0, 14
-	stw		r8,  0x0000(r14)
+	stw		r8,  0x0000(r14);store invalidated version of entry
-	slwi	r9, r4, 12
+	slwi	r9, r4, 12	;get page number of address
 	sync	
 	tlbie	r9
-	beq-	VMDoSomethingWithTLB_0x28
+	beq-	@is_601
 	sync	
 	tlbsync	
 
-VMDoSomethingWithTLB_0x28
+@is_601
 	sync	
 	isync	
 	lwz		r9,  0x0004(r14)
@@ -1821,69 +1790,50 @@ VMDoSomethingWithTLB_0x28
 	rlwimi	r16, r9, 29, 27, 27
 	rlwimi	r16, r9, 27, 28, 28
 	mtcrf	 0x07, r16
-	blr		
+	blr
 
 
 
-;	                       VMDoSomeIO                       
+;updates stored PTE and HTAB entry for PTE
-
+;r16 is PTE value
-;	Xrefs:
+;r15 is address of stored PTE
-;	getPTEntryGivenPage
+;r8 is lower word of HTAB entry
-;	VMIsUnmodified
+;r9 is upper word of HTAB entry
-;	VMMakePageCacheable
+;r14 is address of HTAB entry
-;	VMMakePageWriteThrough
+EditPTEInHTAB	;	OUTSIDE REFERER
-;	PageSetCommon
-;	VMMakePageNonCacheable
-;	VMMarkCleanUnused
-;	VMMarkResident
-;	setPTEntryGivenPage
-;	VMShouldClean
-;	major_0x09b40
-;	major_0x0b144
-
-VMDoSomeIO	;	OUTSIDE REFERER
 	stw		r16,  0x0000(r15)
-
+;just updates HTAB entry
-VMDoSomeIO_0x4	;	OUTSIDE REFERER
+EditPTEOnlyInHTAB	;	OUTSIDE REFERER
-	stw		r9,  0x0004(r14)
+	stw		r9,  0x0004(r14);upper word of HTAB entry contains valid bit
 	eieio	
 	stw		r8,  0x0000(r14)
 	sync	
-	blr		
+	blr
 
 
 
-;	                     major_0x09b40                      
+;Removes a page from the HTAB.
-
+;Called right after GetPARPageInfo, with either a bl or a bltl cr5
-;	Xrefs:
+;
-;	VMFinalInit
+;also updates NK statistics?
-;	VMInit
+;r9 is low word of HTAB entry
-;	VMExchangePages
+;r14 ia address of HTAB entry
-;	VMLRU
+;r15 is address of stored PTE
-;	VMMakePageCacheable
+;r16 is PTE value
-;	VMMakePageWriteThrough
+RemovePTEFromHTAB	;	OUTSIDE REFERER
-;	VMMakePageNonCacheable
+	lwz		r8,  0x0e98(r1);update a value in NanoKernelInfo
-;	VMMarkBacking
+	rlwinm	r16, r16,  0, 21, 19	;update PTE flags to indicate not in HTAB
-;	VMMarkCleanUnused
-;	VMMarkResident
-;	setPTEntryGivenPage
-;	VMAllocateMemory
-;	major_0x0b144
-
-major_0x09b40	;	OUTSIDE REFERER
-	lwz		r8,  0x0e98(r1)
-	rlwinm	r16, r16,  0, 21, 19
 	addi	r8, r8,  0x01
 	stw		r8,  0x0e98(r1)
-	rlwimi	r16, r9,  0,  0, 19
+	rlwimi	r16, r9,  0,  0, 19	;move page# back into PTE
 	li		r8, -0x01
-	stw		r8,  0x0340(r1)
+	stw		r8,  KDP. MinusOne1(r1)
-	stw		r8,  0x0348(r1)
+	stw		r8,  KDP. MinusOne2(r1)
-	stw		r8,  0x0350(r1)
+	stw		r8,  KDP. MinusOne3(r1)
-	stw		r8,  0x0358(r1)
+	stw		r8,  KDP. MinusOne4(r1)
-	li		r8,  0x00
+	li		r8,  0x00	;0 upper HTAB word
-	li		r9,  0x00
+	li		r9,  0x00	;0 lower HTAB word
-	b		VMDoSomeIO
+	b		EditPTEInHTAB	;update stored PTE and invalidate HTAB entry
 
 VMSecondLastExportedFunc	;	OUTSIDE REFERER
 	lwz		r8, KDP.PTEGMask(r1)
@@ -1893,7 +1843,7 @@ VMSecondLastExportedFunc	;	OUTSIDE REFERER
 ;	                   VMLastExportedFunc                   
 
 ;	Xrefs:
-;	major_0x09b40
+;	RemovePTEFromHTAB
 
 
 VMLastExportedFunc
@@ -1977,9 +1927,9 @@ VMLastExportedFunc_0xd7
 	mr		r28, r16
 	mr		r26, r14
 	lwz		r9, KDP.PrimaryAddrRangePages(r1)
-	bl		VeryPopularFunction
+	bl		GetPARPageInfo
 	mtlr	r6
-	b		VMDoSomethingWithTLB
+	b		RemovePageFromTLB