boot3/Patches/DeCompressCommon.A
Elliot Nunn 5b0f0cc134 Bring in CubeE sources
Resource forks are included only for .rsrc files. These are DeRezzed into their data fork. 'ckid' resources, from the Projector VCS, are not included.

The Tools directory, containing mostly junk, is also excluded.
2017-12-26 10:02:57 +08:00

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;
; File: DeCompressDefProc1.a
; By Donn Denman
;
; Contains: parts of the decompress defprocs that are common to all.
;
; Copyright: © 1990 by Apple Computer, Inc., all rights reserved.
;
; Change History (most recent first):
;
; <4> 8/14/90 DD Changed variable lookup at FetchData and assignment at
; RememberData to use unsigned word offsets.
; <3> 7/24/90 gbm Fix branches to next instruction, but don't break debug mode...
; :)
; <2> 4/18/90 DD Added RunLength Encoding and Delta Encoding variations.
; <1> 4/12/90 DD first checked in today
; BBS versions above:
;___________________________________________________________________________________________________
********************************************************************************************
*
* Procedure UnPackData(SourcePtr, DestPtr, VarTable: ptr; VarTableSize: Longint);
*
* Description: Unpack the data from the source pointer to the dest pointer.
* The unpacking is automatically terminated when the end token is reached.
*
*
********************************************************************************************
UnPackFrame Record {A6Link},Decr
SourcePtr DS.L 1
DestPtr DS.L 1
VarTablePtr DS.L 1
VarTableSize DS.L 1
ReturnAddress DS.L 1
A6Link DS.L 1
LocalSize DS.L 0
EndR
With UnpackFrame
UnPackData
Link A6,#LocalSize ;do the unpack from ptr A0 into pointer in A1.
MoveM.L D0-D3/A0-A4,-(SP)
; Set up the registers, for fast handling.
Move.L SourcePtr(A6),A4 ;input stream.
Move.L DestPtr(A6),A1 ;output stream.
Lea CodeDispatchTable,A2 ;dispatch table.
Move.L VarTablePtr(A6),A3 ;variable table.
Move.L VarTableSize(A6),D0 ; table size.
Bsr InitRemember ;init the var table.
Bra UnpackLoop ; now go to the unpack loop.
ExitUnpack
MoveM.L (SP)+,D0-D3/A0-A4
UnLk A6
Move.L (SP)+,A0
Add #SourcePtr-ReturnAddress,SP
Jmp (A0)
EndWith
********************************************************************************************
*
* GetEncodedValue
*
* Description: gets the value pointed to by A4 into D0.L. The values are encoded:
*
* Tag Range computation method
* --- ----- ------------------
* 0..127 0,127 Tag[0]
* 128..254 -16384,16127 (Tag[0]-$C0)*$100+Tag[1]
* 255 same as Long Tag[1]<<24 + Tag[2]<<16 + Tag[3]<<8 + Tag[4]
*
* Input: A4: pointer to tags.
*
* Output: A0: points past tags.
* D0: value long.
*
*
********************************************************************************************
GetEncodedValue Head
; try byte encoding, cuz it is so easy.
MoveQ #0,D0
Move.B (A4)+,D0
Bpl.S @HaveValue ;got the result already.
; is it long encoded?
Cmp.B #FourByteValue,D0 ;long?
Beq.S @FetchLong ;yep, that's fairly easy too.
; word encoded value.
Sub.W #TwoByteValue*3/2,D0 ;cut back the range, toggle the psuedo sign bit.
Asl.W #8,D0 ;shift by a byte (*256).
Asl.W #1,D0 ;shift away the top bit.
ASR.W #1,D0 ;sign extend the top bit.
Move.B (A4)+,D0 ;get the next byte.
Ext.L D0 ;sign extend to a long value.
Bra.S @HaveValue
; long encoding
@FetchLong
Move.B (A4)+,D0 ;add in the next byte.
Asl.W #8,D0 ;shift by a byte (*256).
Move.B (A4)+,D0 ;add in the next byte.
Asl.L #8,D0 ;shift by a byte (*256).
Move.B (A4)+,D0 ;add in the next byte.
Asl.L #8,D0 ;shift by a byte (*256).
Move.B (A4)+,D0 ;add in the next byte.
@HaveValue
Tail
;
; CopyWithLength - copy the data following an encoded length.
;
CopyWithLength
Bsr GetEncodedValue ;get the value into D0.
IF delta=2 THEN
Add.W D0,D0 ;double the value if we are processing word chucks.
EndIF
;BRA.S CopyData ;fall through
;
; CopyData - copy the data already knowing the word length.
;
CopyData
Bra.S @Sub1FirstTime
@CopyData
Move.B (A4)+,(A1)+ ;copy a byte.
@Sub1FirstTime
DBRA D0,@CopyData
Rts
;
; RememberLiteral - copy the data already knowing the word length.
; Also add this literal to the Var Table.
;
RememberLiteral
Bsr.S RememberData ;stuff the data pointed to by A4, for length D0 into the var table.
; fall through to CopyLiteralAndLoop
;
; CopyLiteralAndLoop - copy the data pointed to by the input into the output and loop.
;
CopyLiteralAndLoop
Bsr.S CopyData
Bra UnpackLoop
;
; RememberWithLength - copy the data preceeded by a byte length.
; Also add this literal to the Var Table.
;
RememberWithLength
Bsr GetEncodedValue ;get the value into D0.
IF delta=2 THEN
Add.W D0,D0 ;double the value if we are processing word chucks.
EndIF
Bsr.S RememberData ;stuff the data pointed to by A4, for length D0 into the var table.
Bra.S CopyData
;
; InitRemember - Init the var table.
; Entry: A3 - Var Table.
; D0 - Table size.
;
InitRemember
Move.W D0,VarsList(A3) ;first entry points to the end of the table.
Move.W #2+VarsList,NextVarIndex(A3) ;point to the next var entry.
Rts
;
; RememberData - stuff the data pointed to by A4, for length D0 into the var table.
;
; Entry: A4 - Pointer to the data.
; D0 - length of the data.
; A3 - Var Table.
;
; Exit: A1,D0 - preserved.
; A0,D1 Trashed.
;
RememberData
MoveM.L D0/A1,-(SP)
MoveQ #0,D1
Move.W NextVarIndex(A3),D1 ;get the index into the next var.
AddQ.W #2,NextVarIndex(A3) ;bump the index.
Lea -2(A3,D1.L),A0 ;point to the previous data offset.
Move.W (A0)+,D1 ;it defines where my new string must end.
Sub.W D0,D1 ;compute my new offset.
Move.W D1,(A0) ;put my offset in place.
; Debugging
IF DoDebug > 0 THEN
Lea 0(A3,D1.L),A1 ;point to my data loc.
Cmp.L A0,A1
BGT.S @NoOverFlow
BreakError 'Variable Table Over Flow!'
@NoOverFlow
ENDIF
; Debugging
Lea 0(A3,D1.L),A0 ;point to my data loc.
Move.L A4,A1
Bsr.S BlockMoveBytes
MoveM.L (SP)+,D0/A1
Rts
;
; BlockMoveBytes - block moves bytes from (A1)+ to (A0)+ for D0.W.
;
BlockMoveBytes
Bra.S @Sub1FirstTime
@CopyData
Move.B (A1)+,(A0)+ ;copy a byte.
@Sub1FirstTime
DBRA D0,@CopyData
Rts
;
; ReuseByte2Length - Reuse the data indexed by the following byte, to add 256 to.
;
ReuseByte2Length
MoveQ #0,D0
Move.B (A4)+,D0 ;get the length from the input stream
Add.W #Max1ByteReuse+256,D0 ;bump by the number of vars we can ref in one byte.
Bra.S FetchData ;call FetchData.
;
; ReuseWordLength - copy the data following a word length.
;
ReuseWordLength
MoveQ #0,D0
Move.B (A4)+,D0 ;get the length from the input stream
Asl.W #8,D0 ;shift into high byte.
Bra.S ReuseLowByte
;
; ReuseByteLength - Reuse the data indexed by the following byte.
;
ReuseByteLength
MoveQ #0,D0
ReuseLowByte
Move.B (A4)+,D0 ;get the length from the input stream
Add.W #Max1ByteReuse,D0 ;bump by the number of vars we can ref in one byte.
;Bra.S FetchData ;call FetchData.
;
; FetchData - retrieve the data from index D0 of the var table.
;
; Entry: A1 - Pointer to the output stream.
; D0 - index the data.
; A3 - Var Table.
;
; Exit: A0,D0,D1 Trashed.
;
FetchData
Add.W D0,D0 ;make the index into an offset.
; Debugging
IF DoDebug > 0 THEN
Cmp.W NextVarIndex(A3),D0 ;are we indexing too far into the table?
BLo.S @NoProblem
BreakError 'Error - Index beyond end of vars list'
@NoProblem
ENDIF
; Debugging
Lea VarsList(A3,D0),A0 ;point to the previous entry (end of this string).
Move.W (A0)+,D0 ;get the data offset of the previous entry.
MoveQ #0,D1 ;clear high word, so unsigned offsets will work.
Move.W (A0),D1 ;get the offset of this entry.
Sub.W D1,D0 ;compute the length of this entry.
Lea 0(A3,D1.L),A0 ;point to the string.
Exg A0,A1 ;point A1 to the string, A0 to the output Stream.
Bsr.S BlockMoveBytes
Move.L A0,A1 ;get output ptr back.
Rts
;
; ReuseData - Reuse the data indexed by the encoded byte.
;
ReuseData
Bsr.S FetchData ;fetch the data from the var table.
Bra UnpackLoop ; go back to the main loop.
HandleExtensions
Move.B (A4)+,D0 ;get the extension opCode.
Beq.S @JumpTableTrans
SubQ.B #RunLengthByteTransCode,D0 ; runlength encoding by bytes?
Blo.S @EntryVectorTrans ; is it an entry vector trans?
Beq RunLengthByteTrans
SubQ.B #DiffWordTransCode-RunLengthByteTransCode,D0 ;peel off the next two cases.
Blo RunLengthWordTrans
Beq DiffWordTrans
SubQ.B #DiffEncLongTransCode-DiffWordTransCode,D0 ;peel off the next two cases.
Blo DiffEncWordTrans
Beq DiffEncLongTrans
BreakError 'got an undefined Extension op-code'
Bra @Return
; EntryVector transformation
; Format is as follows:
; BranchOffset Delta NumEntries Offset0 < Offset1 Offset2 ... OffsetN >
; where each item is an encoded value.
; Offset1...OffsetN is an optional words list that is
; present only if Delta==0. If Delta != 0 then
; the Delta is added to Offset0 to create Offset1 etc.
;
@EntryVectorTrans
MoveM.L D2-D7,-(SP)
Move.W #$6100,D3
Move.W #$4EED,D5
Bsr.S GoGetEncodedValue ;get the initial branch offset.
Move.W D0,D4
Bsr.S GoGetEncodedValue ;get the Delta amount.
Move.W D0,D2
Bsr.S GoGetEncodedValue ;get the number of entries.
Move.W D0,D7
Bsr.S GoGetEncodedValue ;get the inital offset.
Move.W D0,D6
Bra.S @HaveOffset
@ExpandEntryVector
SubQ #8,D4 ;compute the next branch offset.
Tst D2 ;is there an offset list?
Beq.S @GetNextOffset ;if the delta is constant (non-zero) then
Add.W D2,D6 ; compute next offset.
Bra.S @HaveOffset
@GetNextOffset
Bsr.S GoGetEncodedValue ;get the next offset.
Move.W D0,D6
@HaveOffset
MoveM.W D3-D6,(A1) ;output the next entry vector.
AddQ #8,A1 ;move the output pointer past the entry.
DBRA D7,@ExpandEntryVector ;until all entries are done.
MoveM.L (SP)+,D2-D7
Bra.S @Return
; JumpTable transformation
; Format is as follows:
; Seg# NumEntries Delta0 Delta1 Delta2
; where each value is encoded.
;
@JumpTableTrans
MoveM.L D3-D7,-(SP)
Move.W #$3F3C,D3
Move.W #$A9F0,D5
Move.W #6,D6 ;init the offset to our bias.
Bsr.S GoGetEncodedValue ;get the segment number
Move.W D0,D4 ;remember seg
Bsr.S GoGetEncodedValue ;get the number of entries.
Move.W D0,D7
Bra.S @skipLastOffset
@StuffLoop
Bsr.S GoGetEncodedValue ;get the delta plus bias of 6.
SubQ #6,D0 ;adjust the delta by my bias (allows some small negs to be a byte).
Add.W D0,D6 ;add the delta to the last offset.
MoveM.W D3-D6,(A1) ;output the next jump table entry.
AddQ #8,A1
@skipLastOffset
DBRA D7,@StuffLoop ;until all entries are done.
MoveM.W D3-D5,(A1) ;output the next jump table entry.
AddQ #6,A1
MoveM.L (SP)+,D3-D7
@Return
Rts
GoGetEncodedValue
Bra GetEncodedValue ;get the value
RunLengthByteTrans Head
Bsr.S GoGetEncodedValue ;get the value
Move.W D0,D1 ;remember value.
Bsr.S GoGetEncodedValue ;get the rep count.
@RunLengthByte
Move.B D1,(A1)+ ;output the value.
DBRA D0,@RunLengthByte ;loop till all done.
Tail
RunLengthWordTrans Head
Bsr.S GoGetEncodedValue ;get the value
Move.W D0,D1 ;remember value.
Bsr.S GoGetEncodedValue ;get the rep count.
@RunLengthWord
Move.W D1,(A1)+ ;output the value.
DBRA D0,@RunLengthWord ;loop till all done.
Tail
DiffWordTrans Head
Bsr.S GoGetEncodedValue ;get the initial value
Move.L D0,D2 ;remember value.
Bsr.S GoGetEncodedValue ;get the rep count.
Move.L D0,D1
Bra.S @FirstTime
@DiffWord
Move.B (A4)+,D0 ;get the delta
Ext.W D0
Add.W D0,D2 ;add in the signed delta
@FirstTime
Move.W D2,(A1)+ ;output the value.
DBRA D1,@DiffWord ;loop till all done.
Tail
DiffEncWordTrans Head
Bsr.S GoGetEncodedValue ;get the initial value
Move.L D0,D2 ;remember value.
Bsr.S GoGetEncodedValue ;get the rep count.
Move.L D0,D1
Bra.S @FirstTime
@DiffWord
Bsr.S GoGetEncodedValue ;get the delta.
Add.L D0,D2 ;add in the signed delta
@FirstTime
Move.W D2,(A1)+ ;output the value.
DBRA D1,@DiffWord ;loop till all done.
Tail
DiffEncLongTrans Head
Bsr.S GoGetEncodedValue ;get the initial value
Move.L D0,D2 ;remember value.
Bsr.S GoGetEncodedValue ;get the rep count.
Move.L D0,D1
Bra.S @FirstTime
@DiffLong
Bsr.S GoGetEncodedValue ;get the delta.
Add.L D0,D2 ;add in the signed delta
@FirstTime
Move.L D2,(A1)+ ;output the value.
DBRA D1,@DiffLong ;loop till all done.
Tail