From e5d22a77300643f0a3013ad40ccd2b5b76788b42 Mon Sep 17 00:00:00 2001
From: Eric Kunze <eric.kunze@arm.com>
Date: Tue, 15 Dec 2020 15:41:05 -0800
Subject: Disambiguate scale_t in RESIZE command

scale_t is already defined globally for the rescaling.

Move pseudocode for count_leading_zeros to introduction,
and use it in the implementation of CLZ.

Change-Id: I2453bce93b6dd25e870b8a010fc62af4c001cbf9
---
 chapters/ewise_unary.adoc  | 12 +-----------
 chapters/image.adoc        | 16 ++++++++--------
 chapters/introduction.adoc | 19 +++++++++++++++++--
 3 files changed, 26 insertions(+), 21 deletions(-)

diff --git a/chapters/ewise_unary.adoc b/chapters/ewise_unary.adoc
index c64bef7..8cdce3d 100644
--- a/chapters/ewise_unary.adoc
+++ b/chapters/ewise_unary.adoc
@@ -122,17 +122,7 @@ Elementwise count leading zeros operation
 for_each (index in shape) {
     in_t acc = 0
     in_t value1 = tensor_read<in_t>(input1, shape, index)
-    if (value1 == 0) {
-         acc = 32 // input1_width
-    }
-    else {
-         mask = 1 << (32 - 1) // input1_width - 1
-         acc = 0
-         while (mask & value1 == 0) {
-            mask = mask >> 1
-            acc = acc + 1
-         }
-    }
+    acc = count_leading_zeros(value1)
     tensor_write<in_t>(output, shape, index, acc)
 }
 ----
diff --git a/chapters/image.adoc b/chapters/image.adoc
index e8b2917..a8e0219 100644
--- a/chapters/image.adoc
+++ b/chapters/image.adoc
@@ -38,9 +38,9 @@ from the strides.
 
 |Input|in_t*|input|[N,IH,IW,C]|Input tensor
 |Attribute|int*|output_size|[2]|[OH,OW]
-|Attribute|scale_t*|stride|[2]|[stride_y, stride_x]
-|Attribute|scale_t*|offset|[2]|[offset_y, offset_x]
-|Attribute|int|shift|Shift value (must be zero if scale_t is float)
+|Attribute|resize_t*|stride|[2]|[stride_y, stride_x]
+|Attribute|resize_t*|offset|[2]|[offset_y, offset_x]
+|Attribute|int|shift|Shift value (must be zero if resize_t is float)
 |Attribute|mode_t|mode|-|BILINEAR or NEAREST
 |Output|out_t*|output|[N,OH,OW,C]|Output tensor
 |===
@@ -54,13 +54,13 @@ None
 [source,c]
 ----
 // scale assert prevents int32_t accumulator overflow for in_t==int8_t
-assert((scale_t==float && shift==0)||(0<shift && shift<=11));
+assert((resize_t==float && shift==0)||(0<shift && shift<=11));
 assert(stride_x>0 && stride_y>0);
 for_each (0<=n<N, 0<=oy<OH, 0<=ox<OW; 0<=c<C) {
-    unit = (scale_t==float) ? 1.0 : (1<<shift);
+    unit = (resize_t==float) ? 1.0 : (1<<shift);
     y = oy * stride_y + offset_y
     x = ox * stride_x + offset_x
-    if (scale_t==float) {
+    if (resize_t==float) {
         iy = (int)floor(y); dy = y - (float)iy;
         ix = (int)floor(x); dx = x - (float)ix;
     } else {
@@ -92,7 +92,7 @@ for_each (0<=n<N, 0<=oy<OH, 0<=ox<OW; 0<=c<C) {
 *Supported Data Types:*
 
 |===
-|Profile|Mode|scale_t|in_t|out_t
+|Profile|Mode|resize_t|in_t|out_t
 
 |Any|signed 8,  bilinear|int16|int8|int32
 |Any|signed 8,  nearest |int16|int8|int8
@@ -101,7 +101,7 @@ for_each (0<=n<N, 0<=oy<OH, 0<=ox<OW; 0<=c<C) {
 |MI,MT|float            |float|float|float
 |===
 
-*Scaling Modes:*
+*Resize Modes:*
 |===
 |Mode|Description
 
diff --git a/chapters/introduction.adoc b/chapters/introduction.adoc
index 3133f36..da1c1b1 100644
--- a/chapters/introduction.adoc
+++ b/chapters/introduction.adoc
@@ -330,8 +330,9 @@ acc_t apply_sub<acc_t>(acc_t a, acc_t b) {
 }
 ....
 
-The following functions are used in the pseudocode to take maximum, minimum or clip values to a range.
-
+The following functions are used in the pseudocode to take maximum,
+minimum, clip values to a range, or count leading zeros.
+[[count_leading_zeros]]
 ....
 <type> apply_max<type>(<type> a, <type> b) {
     if (a >= b) return a; else return b;
@@ -347,6 +348,20 @@ The following functions are used in the pseudocode to take maximum, minimum or c
     value = apply_min(value, max_val);
     return value;
 }
+
+int32_t count_leading_zeros(int32_t a) {
+    int32_t acc = 32;
+    if (a != 0) {
+        uint32_t mask;
+        mask = 1 << (32 - 1); // width of int32_t - 1
+        acc = 0;
+        while ((mask & a) == 0) {
+            mask = mask >> 1;
+            acc = acc + 1;
+        }
+    }
+    return acc;
+}
 ....
 
 ==== Quantized Convolutions
-- 
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