diff --git a/arch/arm/core/cortex_m/scb.c b/arch/arm/core/cortex_m/scb.c
index 8deb9f3792..04c71e268d 100644
--- a/arch/arm/core/cortex_m/scb.c
+++ b/arch/arm/core/cortex_m/scb.c
@@ -86,7 +86,7 @@ void _ScbNumPriGroupSet(unsigned int n /* number of priorities */
 	__ASSERT(_IsPowerOfTwo(n) && (n <= 128),
 		 "invalid number of priorities");
 
-	set = find_first_set(n);
+	set = find_lsb_set(n);
 
 	reg.val = __scs.scb.aircr.val;
 
diff --git a/arch/x86/core/intconnect.c b/arch/x86/core/intconnect.c
index e192347a9a..4bb056e67b 100644
--- a/arch/x86/core/intconnect.c
+++ b/arch/x86/core/intconnect.c
@@ -538,11 +538,11 @@ int _IntVecAlloc(unsigned int priority)
 	 * The interrupt_vectors_allocated[] entry specified by 'entryToScan' is a 32-bit
 	 * quantity and thus represents the vectors for a pair of priority
 	 *levels.
-	 * Use find_last_set() to scan for the upper of the 2, and find_first_set() to
+	 * Use find_msb_set() to scan for the upper of the 2, and find_lsb_set() to
 	 *scan
 	 * for the lower of the 2 priorities.
 	 *
-	 * Note that find_first_set/find_last_set returns bit position from 1 to 32,
+	 * Note that find_lsb_set/find_msb_set returns bit position from 1 to 32,
 	 * or 0 if the argument is zero.
 	 */
 
@@ -551,7 +551,7 @@ int _IntVecAlloc(unsigned int priority)
 	if ((priority % 2) == 0) {
 		/* scan from the LSB for even priorities */
 
-		fsb = find_first_set(interrupt_vectors_allocated[entryToScan]);
+		fsb = find_lsb_set(interrupt_vectors_allocated[entryToScan]);
 
 #if defined(DEBUG)
 		if ((fsb == 0) || (fsb > 16)) {
@@ -568,7 +568,7 @@ int _IntVecAlloc(unsigned int priority)
 	} else {
 		/* scan from the MSB for odd priorities */
 
-		fsb = find_last_set(interrupt_vectors_allocated[entryToScan]);
+		fsb = find_msb_set(interrupt_vectors_allocated[entryToScan]);
 
 #if defined(DEBUG)
 		if ((fsb == 0) || (fsb < 17)) {
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 07fd2c21ae..48113f11c9 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -257,7 +257,7 @@ static inline int pci_bar_params_get(union pci_addr_reg pci_ctrl_addr,
 	addr = bar_config & mask;
 	if (addr != 0) {
 		/* calculate the size of the BAR memory required */
-		dev_info->size = 1 << (find_first_set(addr) - 1);
+		dev_info->size = 1 << (find_lsb_set(addr) - 1);
 	}
 
 	return 0;
diff --git a/include/arch/arc/v2/ffs.h b/include/arch/arc/v2/ffs.h
index 0273459d86..265f08a5fa 100644
--- a/include/arch/arc/v2/ffs.h
+++ b/include/arch/arc/v2/ffs.h
@@ -42,18 +42,18 @@ ARC-specific nanokernel ffs interface. Included by ARC/arch.h.
 
 /**
  *
- * @brief Find First Set bit (searching from most significant bit)
+ * @brief find most significant bit set in a 32-bit word
  *
- * This routine finds the last bit set in the argument passed it and returns
- * the index of that bit.  Bits are numbered starting at 1 from the least
- * significant bit.  A return value of zero indicates that the value passed
- * is zero.
+ * This routine finds the first bit set starting from the most significant bit
+ * in the argument passed in and returns the index of that bit.  Bits are
+ * numbered starting at 1 from the least significant bit.  A return value of
+ * zero indicates that the value passed is zero.
  *
- * @return most significant bit set
+ * @return most significant bit set, 0 if @a op is 0
  */
 
 #if defined(__GNUC__)
-static ALWAYS_INLINE unsigned int find_last_set(unsigned int op)
+static ALWAYS_INLINE unsigned int find_msb_set(unsigned int op)
 {
 	unsigned int bit;
 
@@ -71,18 +71,18 @@ static ALWAYS_INLINE unsigned int find_last_set(unsigned int op)
 
 /**
  *
- * @brief Find first set bit (searching from the least significant bit)
+ * @brief find least significant bit set in a 32-bit word
  *
- * This routine finds the first bit set in the argument passed it and
- * returns the index of that bit.  Bits are numbered starting
- * at 1 from the least significant bit.  A return value of zero indicates that
- * the value passed is zero.
+ * This routine finds the first bit set starting from the least significant bit
+ * in the argument passed in and returns the index of that bit.  Bits are
+ * numbered starting at 1 from the least significant bit.  A return value of
+ * zero indicates that the value passed is zero.
  *
- * @return least significant bit set
+ * @return least significant bit set, 0 if @a op is 0
  */
 
 #if defined(__GNUC__)
-static ALWAYS_INLINE unsigned int find_first_set(unsigned int op)
+static ALWAYS_INLINE unsigned int find_lsb_set(unsigned int op)
 {
 	unsigned int bit;
 
diff --git a/include/arch/arm/CortexM/asm_inline_gcc.h b/include/arch/arm/CortexM/asm_inline_gcc.h
index e9184910cb..7b59a6347f 100644
--- a/include/arch/arm/CortexM/asm_inline_gcc.h
+++ b/include/arch/arm/CortexM/asm_inline_gcc.h
@@ -54,17 +54,17 @@
 
 /**
  *
- * @brief Find first set bit (searching from most significant bit)
+ * @brief find most significant bit set in a 32-bit word
  *
- * This routine finds the last bit set in the argument passed it and returns
- * the index of that bit.  Bits are numbered starting at 1 from the least
- * significant bit.  A return value of zero indicates that the value passed
- * is zero.
+ * This routine finds the first bit set starting from the most significant bit
+ * in the argument passed in and returns the index of that bit.  Bits are
+ * numbered starting at 1 from the least significant bit.  A return value of
+ * zero indicates that the value passed is zero.
  *
- * @return most significant bit set
+ * @return most significant bit set, 0 if @a op is 0
  */
 
-static ALWAYS_INLINE unsigned int find_last_set(unsigned int op)
+static ALWAYS_INLINE unsigned int find_msb_set(unsigned int op)
 {
 	unsigned int bit;
 
@@ -82,17 +82,17 @@ static ALWAYS_INLINE unsigned int find_last_set(unsigned int op)
 
 /**
  *
- * @brief Find first set bit (from the least significant bit)
+ * @brief find least significant bit set in a 32-bit word
  *
- * This routine finds the first bit set in the argument passed it and
- * returns the index of that bit.  Bits are numbered starting
- * at 1 from the least significant bit.  A return value of zero indicates that
- * the value passed is zero.
+ * This routine finds the first bit set starting from the least significant bit
+ * in the argument passed in and returns the index of that bit.  Bits are
+ * numbered starting at 1 from the least significant bit.  A return value of
+ * zero indicates that the value passed is zero.
  *
- * @return least significant bit set
+ * @return least significant bit set, 0 if @a op is 0
  */
 
-static ALWAYS_INLINE unsigned int find_first_set(unsigned int op)
+static ALWAYS_INLINE unsigned int find_lsb_set(unsigned int op)
 {
 	unsigned int bit;
 
diff --git a/include/arch/x86/asm_inline_gcc.h b/include/arch/x86/asm_inline_gcc.h
index a2541b0832..5b92ae63fc 100644
--- a/include/arch/x86/asm_inline_gcc.h
+++ b/include/arch/x86/asm_inline_gcc.h
@@ -97,24 +97,24 @@ static inline __attribute__((always_inline)) void _do_irq_unlock(void)
 
 /**
  *
- * @brief Find first set bit searching from the LSB (inline)
+ * @brief find least significant bit set in a 32-bit word
  *
- * This routine finds the first bit set in the argument passed it and
- * returns the index of that bit.  Bits are numbered starting
- * at 1 from the least significant bit to 32 for the most significant bit.
- * A return value of zero indicates that the value passed is zero.
+ * This routine finds the first bit set starting from the least significant bit
+ * in the argument passed in and returns the index of that bit.  Bits are
+ * numbered starting at 1 from the least significant bit.  A return value of
+ * zero indicates that the value passed is zero.
  *
- * @return bit position from 1 to 32, or 0 if the argument is zero.
+ * @return least significant bit set, 0 if @a op is 0
  *
- * INTERNAL
- * For Intel64 (x86_64) architectures, the 'cmovzl' can be removed
- * and leverage the fact that the 'bsfl' doesn't modify the destination operand
- * when the source operand is zero.  The "bitpos" variable can be preloaded
- * into the destination register, and given the unconditional ++bitpos that
- * is performed after the 'cmovzl', the correct results are yielded.
+ * @internal
+ * For Intel64 (x86_64) architectures, the 'cmovzl' can be removed and leverage
+ * the fact that the 'bsfl' doesn't modify the destination operand when the
+ * source operand is zero.  The "bitpos" variable can be preloaded into the
+ * destination register, and given the unconditional ++bitpos that is performed
+ * after the 'cmovzl', the correct results are yielded.
  */
 
-static ALWAYS_INLINE unsigned int find_first_set(unsigned int op)
+static ALWAYS_INLINE unsigned int find_lsb_set(unsigned int op)
 {
 	int bitpos;
 
@@ -147,24 +147,24 @@ static ALWAYS_INLINE unsigned int find_first_set(unsigned int op)
 
 /**
  *
- * @brief Find first set bit searching from the MSB (inline)
+ * @brief find most significant bit set in a 32-bit word
  *
- * This routine finds the first bit set in the argument passed it and
- * returns the index of that bit.  Bits are numbered starting
- * at 1 from the least significant bit to 32 for the most significant bit.
- * A return value of zero indicates that the value passed is zero.
+ * This routine finds the first bit set starting from the most significant bit
+ * in the argument passed in and returns the index of that bit.  Bits are
+ * numbered starting at 1 from the least significant bit.  A return value of
+ * zero indicates that the value passed is zero.
  *
- * @return bit position from 1 to 32, or 0 if the argument is zero.
+ * @return most significant bit set, 0 if @a op is 0
  *
- * INTERNAL
- * For Intel64 (x86_64) architectures, the 'cmovzl' can be removed
- * and leverage the fact that the 'bsfl' doesn't modify the destination operand
- * when the source operand is zero.  The "bitpos" variable can be preloaded
- * into the destination register, and given the unconditional ++bitpos that
- * is performed after the 'cmovzl', the correct results are yielded.
+ * @internal
+ * For Intel64 (x86_64) architectures, the 'cmovzl' can be removed and leverage
+ * the fact that the 'bsfl' doesn't modify the destination operand when the
+ * source operand is zero.  The "bitpos" variable can be preloaded into the
+ * destination register, and given the unconditional ++bitpos that is performed
+ * after the 'cmovzl', the correct results are yielded.
  */
 
-static ALWAYS_INLINE unsigned int find_last_set(unsigned int op)
+static ALWAYS_INLINE unsigned int find_msb_set(unsigned int op)
 {
 	int bitpos;
 
diff --git a/kernel/microkernel/k_server.c b/kernel/microkernel/k_server.c
index d7e71d90ad..b0da40cd0e 100644
--- a/kernel/microkernel/k_server.c
+++ b/kernel/microkernel/k_server.c
@@ -66,14 +66,14 @@ static struct k_proc *next_task_select(void)
 	int K_PrioListIdx;
 
 #if (CONFIG_NUM_TASK_PRIORITIES <= 32)
-	K_PrioListIdx = find_first_set(_k_task_priority_bitmap[0]) - 1;
+	K_PrioListIdx = find_lsb_set(_k_task_priority_bitmap[0]) - 1;
 #else
 	int bit_map;
 	int set_bit_pos;
 
 	K_PrioListIdx = -1;
 	for (bit_map = 0; ; bit_map++) {
-		set_bit_pos = find_first_set(_k_task_priority_bitmap[bit_map]);
+		set_bit_pos = find_lsb_set(_k_task_priority_bitmap[bit_map]);
 		if (set_bit_pos) {
 			K_PrioListIdx += set_bit_pos;
 			break;