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Fix more than 256 codes of same length. 

Fix all 256 literal codes of same length.

Fixes #2
This commit is contained in:
Piotr Fusik 2017-11-07 19:20:20 +01:00
parent 02c09a514e
commit 0608c9adef
2 changed files with 31 additions and 13 deletions
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4
README.md
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@ -15,8 +15,8 @@ Use [xasm](https://github.com/pfusik/xasm).
The routine uses three memory areas:
* `inflate` - code and constants (492 bytes)
* `inflate_data` - uninitialized data (764 bytes)
* `inflate` - code and constants (508 bytes)
* `inflate_data` - uninitialized data (765 bytes)
* `inflate_zp` - variables on zero page
You must select these locations at compile time, for example:

40
inflate.asx
View File

@ -1,11 +1,11 @@
; inflate - uncompress data stored in the DEFLATE format
; by Piotr Fusik <fox@scene.pl>
; Last modified: 2017-11-06
; Last modified: 2017-11-07
; Compile with xasm (http://xasm.atari.org/), for example:
; xasm inflate.asx /l /d:inflate=$b700 /d:inflate_data=$b900 /d:inflate_zp=$f0
; inflate is 492 bytes of code and constants
; inflate_data is 764 bytes of uninitialized data
; inflate is 508 bytes of code and constants
; inflate_data is 765 bytes of uninitialized data
; inflate_zp is 10 bytes on page zero
@ -288,6 +288,7 @@ buildHuffmanTree
buildHuffmanTree_countCodeLengths
ldx literalSymbolCodeLength,y
inc nBitCode_literalCount,x
sne:stx allLiteralsCodeLength
cpy #CONTROL_SYMBOLS
bcs buildHuffmanTree_noControlSymbol
ldx controlSymbolCodeLength,y
@ -335,11 +336,33 @@ fetchCode_nextBit
jsr getBit
rol @
inx
bcs fetchCode_ge256
; are all 256 literal codes of this length?
cpx allLiteralsCodeLength
beq fetchCode_allLiterals
; is it literal code of length X?
sub nBitCode_literalCount,x
bcc fetchCode_literal
bcs fetchCode_tryControl
; literal code
fetchCode_literal
; clc
adc nBitCode_literalOffset,x
fetchCode_allLiterals
tax
lda codeToLiteralSymbol,x
clc
rts
; code >= 256, must be control
fetchCode_ge256
; sec
sbc nBitCode_literalCount,x
sec
; is it control code of length X?
fetchCode_tryControl
; sec
sbc nBitCode_controlCount,x
bcs fetchCode_nextBit
; control code
; clc
adc nBitCode_controlOffset,x
tax
@ -348,13 +371,6 @@ fetchCode_nextBit
tax
; sec
rts
fetchCode_literal
; clc
adc nBitCode_literalOffset,x
tax
lda codeToLiteralSymbol,x
clc
rts
; Read A minus 1 bits, but no more than 8
getAMinus1BitsMax8
@ -446,6 +462,8 @@ nBitCode_literalOffset
org *+2*TREE_SIZE
nBitCode_controlOffset
org *+2*TREE_SIZE
allLiteralsCodeLength
org *+1
codeToLiteralSymbol
org *+256