Vdc decompress reimagined

Have you updated your code for the lsr optimization we talked about yet?

Sorry for the double-post, but I tried download from MS and got a really weird error... so I tried to contact their tech support and got yet another error...

Can you say DOUBLE FAIL? Good... I knew you could!

My first attempt to download (with ADMIN privledge) failed... so I tried to delete that folder and got an error... so that is when I tried to "Contact" Microsoft, and that is when I got *another* error which says JavaScript must be enabled... well it *is* enabled so there is some problem with Mircosoft directly... and when I try to "Contact" them, that is when I get the 2nd error.

If that ain't the definition of DOUBLE FAIL, then please correct me!

In the meantime, I have 0-byte file of "ms_community.exe" that I can't delete (even with admin privledges!)... and obviously I still need to download the real (non-zero-byte) install of "ms_community.exe"

Yeah, I know you guys aren't MS support staff, so I don't expect you to have an answer, but I just wanted to vent about how modern systems are just as pathetic (or more) compared to "old-school" technology!!!! Did I mention !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Before reinstalling clear all references to it in the registry. I have found that to help with troublesome installs.

Good news! New Code everyone!

I have redone the code for my compressor from the ground up. Now to release it for beta.

After looking at what I want to compress, I made the following changes:

1) reduce the code to rle and far copy. rle is 1 to 127 and 0 = 256. (LLLLLLL)1 ,(byte value)

2) the far copy is far copy is 2k with 2 to 8 bytes via 1 to 7 with 0 = 64 byte far copy. 2 bytes like this (HHH)(NNN)10 LLLLLLLL. H = high bits of distance, L = low bits of distance and N = bits of length.

3) If I did it right the windows part should use the setup install thing.

4) the commodore side loads at $1300. you could recompile elsewhere. The source address of the decompress file should be at $20 in low/high byte format. sys $1300,,x,y where x is high byte and y is low byte of vdc address you are decompressing to.

now for the source code. assembly
/*
***********************************************************************************************
vdc decompress 29.01,2015
by vdc 8x2
sys 1300,,x,y

.x high byte vdc mem target
.y low byte vdc mem target
$20 is normal mem in lo/hi byte format
***********************************************************************************************
*/
.const VDCdata = $d601
.const VDCreg  = $d600
.const MemAddress = $12
.const CopyBytes = $1e
.const CopySource = $20
.const ReadWrite = $1f
.const Source = $fd
.const Scratch = $fb
.const CopyFlag = $18

.macro MoValue(fromem,tomem) {
lda #fromem
sta tomem
}

.macro VDCwait(temp) {
Loop: bit VDCreg
bpl Loop
}

.macro Reljmp (address) {
clc
bcc address
}

.macro WordInc(Address) {
inc Address
bne NoRoll
inc Address+1
NoRoll:
}

.pc = $1300 "Vdc Decompress"

// Subroutine code

start:
:MoValue(MemAddress,VDCreg)
:VDCwait(0)    // wait for vdc to be ready
stx VDCdata
:MoValue(MemAddress + 1,VDCreg)
sty VDCdata
jmp Parse

MainLoop: :WordInc(Source)
:VDCwait(0)

Parse: ldy #$00
lda (Source),y
lsr
bcs RLEcode //run length decoding
lsr
bcs CopyCode //our vdc copy code
RawCode: tax
bne NotEnd
rts //done peace out.
NotEnd: :MoValue(ReadWrite,VDCreg)
{
Loop: :WordInc(Source)
lda (Source),y //get next byte
:VDCwait(0)
sta VDCdata
dex
bne Loop
}
beq MainLoop

RLEcode: {
tax
bne XnotZero
dex // the count is zero so make it 255
XnotZero: :MoValue(CopyFlag,VDCreg)
lda VDCdata
and $7f
sta VDCdata // set flag for fill
:MoValue(ReadWrite,VDCreg)
:VDCwait(0) // set reg to write
:WordInc(Source)
lda (Source),y // what data to write
sta VDCdata
:MoValue(CopyBytes,VDCreg)
stx VDCdata // Fill x to vdc mem
jmp MainLoop
}
CopyCode: {
pha //save to stack for high bits later
and #$07 //3 bits for 2 to 8 and 64 with zero
bne NotZero
lda #$3f //it zero so make it 63
NotZero: tax //put the copy count into x
inx //x must be +1 to make it (2 to 8) or 64
:MoValue(CopyFlag,VDCreg)
lda VDCdata
ora #$80 //set copy bit
sta VDCdata
pla //get value back off stack and shift for high bits
lsr
lsr
lsr
sta Scratch //save the high bits
:WordInc(Source)
lda (Source),y
sta Scratch + 1 //save the low byte
:MoValue(MemAddress + 1,VDCreg)
lda VDCdata
sec //set carry we subtracting
sbc Scratch + 1
sta Scratch + 1 // save low byte
:MoValue(MemAddress,VDCreg)
:VDCwait(0)
lda VDCdata //got high byte
sbc Scratch
ldy #CopySource
sty VDCreg
sta VDCdata //store high byte address in vdc reg
lda Scratch + 1
iny //now for low byte
sty VDCreg
sta VDCdata
:MoValue(CopyBytes,VDCreg)
:VDCwait(0)
stx VDCdata //start our copy
jmp MainLoop
}
end:

// Data

Some of the visual basic code
Public Class Form1
   Dim loadButton As Boolean = False
   Dim compressButton As Boolean = False
   Dim saveButton As Boolean = False
   Dim slidingWindow As String
   Dim FutureWindow As String
   Dim distance As UInt32
   Dim compressTarget As String
   Dim progressPointer As UInt32 = 1
   Dim endOfProcess As UInt32
   Dim futurEnd As UInt16 = 256
   Dim outputString As String
   Dim anyCompression(2) As Boolean
   Dim stringCount(2) As UInt32
   Dim howMany As UInt32 = 0
   Dim raw As String

   Private Sub AboutToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles AboutToolStripMenuItem.Click
       AboutBox1.ShowDialog()
   End Sub
   Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
       loadStuff()
   End Sub
   Private Sub LoadToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles LoadToolStripMenuItem.Click
       loadStuff()
   End Sub

   Private Sub loadStuff()
       loadButton = True
       ProgressBar1.Value = 1
       OpenFileDialog1.ShowDialog()
       If OpenFileDialog1.FileName = "" Then
           loadButton = False 'no name so aborted load
           Return
       End If
       Dim bytes = My.Computer.FileSystem.ReadAllBytes(OpenFileDialog1.FileName)
       'convert array into our workstring minus the load address
       compressTarget = ""

       For index = 2 To bytes.GetUpperBound(0)
           compressTarget = compressTarget & Chr(bytes(index))
       Next
       If Len(compressTarget) < 256 Then
           MsgBox("The compressed file must be at least 256 bytes")
           loadButton = False

           Return
       End If
       endOfProcess = Len(compressTarget)
       'load the future window

   End Sub
   Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
       CompresStuff()
   End Sub
   Private Sub CompressToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles CompressToolStripMenuItem.Click
       CompresStuff()
   End Sub
   Private Sub CompresStuff()
       If loadButton = False Then
           MsgBox("load file first.")
           Return
       End If
       progressPointer = 1
       FutureWindow = Mid(compressTarget, 1, 256)
       slidingWindow = ""
       outputString = ""
       raw = ""
       compressButton = True
       ' start of encoding loop
       ProgressBar1.Minimum = 1
       ProgressBar1.Maximum = Me.endOfProcess
       ProgressBar1.Value = 1
       stringCount(0) = 0 'for the raw section
       Do
           For varP = 1 To 2
               stringCount(varP) = 0
               anyCompression(varP) = False
               If varP = 1 Then
                   For relVar = 2 To futurEnd 'checking run length
                       If Mid(FutureWindow, 1, 1) = Mid(FutureWindow, relVar, 1) Then
                           anyCompression(1) = True
                           stringCount(1) = stringCount(1) + 1

                       Else
                           Exit For
                       End If
                   Next
               End If
               If varP = 2 Then
                   For farVar = 1 To 1983
                       If Mid(FutureWindow, 1, 64) = Mid(slidingWindow, farVar, 64) Then
                           'checking for far 64 first
                           anyCompression(2) = True
                           stringCount(2) = 63
                           distance = farVar
                           Exit For
                       End If
                   Next
                   If anyCompression(2) = False Then
                       For x = 8 To 2 Step -1
                           For farVar = 1 To 2047 - x
                               If Mid(FutureWindow, 1, x) = Mid(slidingWindow, farVar, x) Then
                                   anyCompression(2) = True
                                   stringCount(2) = x - 1
                                   distance = farVar
                                   Exit For
                               End If
                           Next
                           If anyCompression(2) = True Then Exit For
                       Next
                   End If
               End If
           Next

           If anyCompression(1) = True And anyCompression(2) = False Then
               'no copy compression so do rle
               Comp1()
           End If
           If anyCompression(1) = False And anyCompression(2) = True Then
               'no rle so do copy compression
               Comp2()
           End If
           If anyCompression(1) = True And anyCompression(2) = True And anyCompression(1) >= anyCompression(2) Then
               'rle is >= copy so do rle compression. the tie goes to rle
               Comp1()
           End If
           If anyCompression(1) = True And anyCompression(2) = True And anyCompression(1) < anyCompression(2) Then
               'rle is < copy  so do copy compression
               Comp2()
           End If
           If anyCompression(1) = False And anyCompression(2) = False Then
               'no compression opportunities, so move to next byte and try again.
               raw = raw & Mid(FutureWindow, 1, 1)
               If Len(raw) = 63 Then
                   outputString = outputString & Chr(63 * 4) & raw
                   raw = ""
               End If
               howMany = 0
           End If
           'MsgBox(stringCount(1) & "   " & stringCount(2))
           updateFuture(stringCount(howMany))
           If progressPointer > endOfProcess Then
               Exit Do
           End If
           ProgressBar1.Value = progressPointer
       Loop
       If raw <> "" Then
           outputString = outputString & Chr(Len(raw) * 4) & raw
           raw = ""
       End If
       ProgressBar1.Value = endOfProcess
       outputString = Chr(0) & outputString & Chr(0) 'padding for start and end of file for the end

   End Sub
   Private Sub Comp1()
       Dim rleCount As UInt32
       If stringCount(1) = 255 Then
           rleCount = 0
       End If
       If stringCount(1) > 127 And stringCount(1) < 255 Then
           stringCount(1) = 127
           rleCount = stringCount(1)
       End If
       If stringCount(1) <= 127 Then
           rleCount = stringCount(1)
       End If
       If raw <> "" Then
           outputString = outputString & Chr(Len(raw) * 4) & raw
           raw = ""
       End If
       outputString = outputString & Chr(rleCount * 2 + 1) & Mid(FutureWindow, 1, 1)
       howMany = 1
   End Sub
   Private Sub Comp2()
       Dim farCount As UInt32
       distance = 2047 - distance 'turning it around to make it be the right distance from futureWindow
       If stringCount(2) = 63 Then
           farCount = 0 '0 will = 64 in the decompression code
       Else
           farCount = stringCount(2)
       End If
       If raw <> "" Then
           outputString = outputString & Chr(Len(raw) * 4) & raw
           raw = ""
       End If
       outputString = outputString & Chr(((((distance And 1792) / 256) * 8) + farCount) * 4 + 2) & Chr(distance And 255)
       '(hhhnnn * 4) +2 first byte, llllllll second byte. distance = hhh,llllllll
       howMany = 2
   End Sub
   Private Sub updateFuture(x As UInt16)
       If x = 0 Then 'process just one sliding window move
           slidingWindow = slidingWindow & Mid(FutureWindow, 1, 1)
           If Len(slidingWindow) > 2047 Then
               slidingWindow = Mid(slidingWindow, 2, 2047) 'make sure it tops out at 2047 bytes
           End If
           FutureWindow = Mid(FutureWindow, 2, 256) & Mid(compressTarget, progressPointer, 1) 'move a byte from furture to sliding
           progressPointer = progressPointer + 1
       Else
           For loop1 As UInt32 = 1 To x + 1 'proccess x+1 sliding window moves
               slidingWindow = slidingWindow & Mid(FutureWindow, 1, 1)
               If Len(slidingWindow) > 2047 Then
                   slidingWindow = Mid(slidingWindow, 2, 2047) 'make sure it tops out at 2047 bytes
               End If
               FutureWindow = Mid(FutureWindow, 2, 256) & Mid(compressTarget, progressPointer, 1) 'move a byte from furture to sliding
               progressPointer = progressPointer + 1
           Next
       End If

   End Sub

   Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
       saveStuff()
   End Sub
   Private Sub SaveToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles SaveToolStripMenuItem.Click
       saveStuff()
   End Sub
   Private Sub saveStuff()
       If loadButton = False Or compressButton = False Then
           MsgBox("Load file or compress before saving.")
       Else
           loadButton = False
           compressButton = False
           saveButton = True
           SaveFileDialog1.FileName = OpenFileDialog1.FileName & ".vdcp"
           SaveFileDialog1.ShowDialog()
           ProgressBar1.Value = 1
           ProgressBar1.Maximum = Len(outputString)
           Dim outputFile(Len(outputString)) As Byte
           For index = 1 To Len(outputString)
               outputFile(index) = Asc(Mid(outputString, index, 1))
               ProgressBar1.Value = index
           Next
           ProgressBar1.Value = Len(outputString)
           My.Computer.FileSystem.WriteAllBytes(SaveFileDialog1.FileName, outputFile, False)
       End If

   End Sub
   Private Sub ExitToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles ExitToolStripMenuItem.Click
       End
   End Sub
End Class


The software is ready for testing. Have at an tell me about any bugs. Let the beta begin!