init files

loader/tools/lzsa/StreamFormat.md

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+# Stream format
+
+The stream format is composed of:
+
+* a header
+* one or more frames
+* a footer
+
+# Header format
+
+The 3-bytes LZSA header contains a signature and a traits byte:
+
+    0    1                2
+    0x7b 0x9e             7 6 5 4 3 2 1
+                          V V V Z Z Z Z
+    <--- signature --->   <- traits ->
+
+Trait bits:
+
+* V: 3 bit code that indicates which block data encoding is used. 0 is LZSA1 and 1 is LZSA2.
+* Z: these bits in the traits are set to 0 for LZSA1 and LZSA2.
+
+# Frame format
+
+Each frame contains a 3-bytes length followed by block data that expands to up to 64 Kb of decompressed data. The block data is encoded either as LZSA1 or LZSA2 depending on the V bits of the traits byte in the header.
+
+    0    1    2
+    DSZ0 DSZ1 U|DSZ2
+
+* DSZ0 (length byte 0) contains bits 0-7 of the block data size
+* DSZ1 (length byte 1) contains bits 8-15 of the block data size
+* DSZ2 (bit 0 of length byte 2) contains bit 16 of the block data size
+* U (bit 7 of length byte 2) is set if the block data is uncompressed, and clear if the block data is compressed.
+* Bits 1..6 of length byte 2 are currently undefined and must be set to 0.
+
+# Footer format
+
+The stream ends with the EOD frame: the 3 length bytes are set to 0x00, 0x00, 0x00, and no block data follows.
+