From 030228552bba6646d602070558825869b7830db2 Mon Sep 17 00:00:00 2001
From: Nathael Pajani <nathael.pajani@ed3l.fr>
Date: Tue, 27 Sep 2016 22:48:39 +0200
Subject: [PATCH] Updated stdlib et utils libs

---
 include/lib/stdlib.h |  2 +-
 include/lib/utils.h  |  6 ++++++
 lib/stdlib.c         |  5 ++++-
 lib/utils.c          | 37 +++++++++++++++++++++++++++++++------
 4 files changed, 42 insertions(+), 8 deletions(-)

diff --git a/include/lib/stdlib.h b/include/lib/stdlib.h
index 9e302fb..9ae275d 100644
--- a/include/lib/stdlib.h
+++ b/include/lib/stdlib.h
@@ -28,7 +28,7 @@
  * Does not check that the base is respected aside for the use of letters in
  *   number representation.
  */
-uint32_t strtoul(uint8_t* str, uint8_t base);
+uint32_t strtoul(const char* str, char** end, uint8_t base);
 
 #endif /* LIB_STDLIB_H */
 
diff --git a/include/lib/utils.h b/include/lib/utils.h
index 838e24d..e8ffac2 100644
--- a/include/lib/utils.h
+++ b/include/lib/utils.h
@@ -48,5 +48,11 @@ uint8_t clz(uint32_t x);
  */
 uint8_t ctz(uint32_t x);
 
+/*
+ * Count bits set
+ */
+uint8_t bits_set(uint32_t x);
+
+
 #endif /* LIB_UTILS_H */
 
diff --git a/lib/stdlib.c b/lib/stdlib.c
index 3b9f0fe..c0a1991 100644
--- a/lib/stdlib.c
+++ b/lib/stdlib.c
@@ -26,7 +26,7 @@
  * Does not check that the base is respected aside for the use of letters in
  *   number representation.
  */
-uint32_t strtoul(uint8_t* str, uint8_t base)
+uint32_t strtoul(const char* str, char** end, uint8_t base)
 {
 	uint32_t val = 0;
 	while (*str != '\0') {
@@ -47,6 +47,9 @@ uint32_t strtoul(uint8_t* str, uint8_t base)
 		}
 		break;
 	}
+	if (end != NULL) {
+		*end = (char*)str;
+	}
 	return val;
 }
 
diff --git a/lib/utils.c b/lib/utils.c
index aaaa2a5..42b4453 100644
--- a/lib/utils.c
+++ b/lib/utils.c
@@ -31,12 +31,15 @@
  * instructions.
  */
 
+
+
 /* Count leading zeroes
- * The following function is an effitient way to implement __builtin_clz().
+ * The following function is an efficient way to implement __builtin_clz(),
+ * or at least a good compromize between memory usage and speed.
  */
 uint8_t clz(uint32_t x)
 {
-	static const uint8_t bval[] = {0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4};
+	static const uint8_t bval_clz[] = {0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4};
 	unsigned int r = 32;
 	if (x >= 0x10000) { /* Quicker than (x & 0xFFFF0000) on a 32bit arm arch */
 		r -= 16;
@@ -50,15 +53,16 @@ uint8_t clz(uint32_t x)
 		r -= 4;
 		x >>= 4;
 	}
-	return r - bval[x];
+	return r - bval_clz[x];
 }
 
 /* Count traling zeroes
- * The following function is an effitient way to implement __builtin_ctz().
+ * The following function is an efficient way to implement __builtin_ctz(),
+ * or at least a good compromize between memory usage and speed.
  */
 uint8_t ctz(uint32_t x)
 {
-	static const uint8_t bval[] = {4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0};
+	static const uint8_t bval_ctz[] = {4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0};
 	unsigned int r = 0;
 	if (x & 0x1) {
 		/* special case for odd value (assumed to happen half of the time) */
@@ -76,5 +80,26 @@ uint8_t ctz(uint32_t x)
 		r += 4;
 		x >>= 4;
 	}
-	return r + bval[(x & 0x0F)];
+	return r + bval_ctz[(x & 0x0F)];
+}
+
+
+
+/*
+ * Count bits set
+ */
+uint8_t bits_set(uint32_t x)
+{
+	static const uint8_t bval_bsets[] = {0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4};
+	uint8_t r = 0; /* Accumulator for the total bits set in x */
+
+	r = bval_bsets[x & 0xFF];
+	x >>= 8;
+	r += bval_bsets[x & 0xFF];
+	x >>= 8;
+	r += bval_bsets[x & 0xFF];
+	x >>= 8;
+	r += bval_bsets[x & 0xFF];
+
+	return r;
 }
-- 
2.43.0