xls:modules:rle: Review: update comments

Signed-off-by: Maciej Dudek <[email protected]>

Author: mtdudek

xls/modules/rle/rle_enc_adv.x

@@ -22,19 +22,32 @@
 // the last packet encoder dumps all the data to the output stream.
 // The behavior of the encoder is presented on the waveform below:
 
-// This encoder is implemented as a net of 4 processes.
-// 1. Reduce stage - this process takes incoming symbols and symbol_valid
-// and reduces them into symbol count pairs. This stage is stateless.
-// 2. Realign stage - this process moves pairs emitted from previous stage
-// so that they are align to the left, it also calculates propagation distance
-// for the first pair.
-// 3. Core stage - this stage is stateful. It takes align pairs,
-// and combines them with its state.It outputs multiple symbol/count pairs.
-// 4 - Adjust Width stage - this stage takes output from the core stage.
+// This encoder is implemented as a net of 4 proc.
+// 1. Reduce step - this process takes incoming symbols and symbol_valid
+// and reduces them into symbol count pairs. This step is stateless.
+// 2. Realign step - this process moves pairs emitted from the reduce step
+// so that they are aligned to the left, it also calculates propagation
+// distance for the first pair.
+// Example behaviours:
+// 1)
+//    input:  [.., (A, 2), .., (B, 2)]
+//    output: [(A, 2), (B, 2), .., ..]
+//    propagation distance: 0
+// 2)
+//    input:  [.., .., (A, 3), (A, 1)]
+//    output: [(A, 3), (A, 1), .., ..]
+//    propagation distance: 1
+// 3. Core step - this step is stateful. It takes align pairs from
+// the realign step, and combines them with its state to create multiple
+// symbol/count pairs output. State is represented by following tuple
+// `<symbol, count, last>`. It contains symbol and count from last pair
+// received from realign step, or current sum of repeating symbol spanning
+// multiple input widths.
+// 4. - Adjust Width step - this step takes output from the core step.
 // If output can handle more or equal number of pairs as
-// input number of symbols. This stage does nothing.
+// input number of symbols. This step does nothing.
 // If the output is narrower than the input,
-// this stage will serialize symbol counter pairs.
+// this step will serialize symbol counter pairs.
 
 
 import std

xls/modules/rle/rle_enc_adv_core.x

@@ -126,7 +126,7 @@ pub proc RunLengthEncoderAdvancedCoreStage<SYMBOL_WIDTH: u32, COUNT_WIDTH: u32,
       ),
     };
 
-    let (symobls_to_send, counts_to_send, last_to_send, pair_count_to_send) =
+    let (symbols_to_send, counts_to_send, last_to_send, pair_count_to_send) =
       match (combine_last, state.prev_last) {
         (false, false) => {
           let idx = total_pair_count - u32:1;
@@ -152,7 +152,7 @@ pub proc RunLengthEncoderAdvancedCoreStage<SYMBOL_WIDTH: u32, COUNT_WIDTH: u32,
 
     let output = (
       EncOutData<SYMBOL_WIDTH, COUNT_WIDTH, INPUT_WIDTH> {
-        symbols: symobls_to_send,
+        symbols: symbols_to_send,
         counts: counts_to_send,
         last: last_to_send,
       },