ffs.diff

diff --git a/firmware/asm/arm/ffs.S b/firmware/asm/arm/ffs.S
index 4e912c5..bebf33f 100644
--- a/firmware/asm/arm/ffs.S
+++ b/firmware/asm/arm/ffs.S
@@ -32,6 +32,10 @@
  *   31 - bit 31 is set
  *   32 - no bits set
  ****************************************************************************/
+#if (ARCH_PROFILE == arch_profile_m)
+    .syntax unified
+    .thumb
+#endif
     .align  2
     .global find_first_set_bit
     .type   find_first_set_bit,%function
@@ -44,6 +48,9 @@ find_first_set_bit:

 #if ARM_ARCH >= 5
     clz     r0, r1                   @ Get lead 0's count
+# if (ARCH_PROFILE == arch_profile_m)
+    it      ne
+# endif
     rsbne   r0, r0, #31              @ lead 0's -> bit index
     bx      lr                       @
 #else
@@ -73,3 +80,4 @@ L_ffs_table:
     .byte   29,  0, 22, 18, 28, 17, 16,  0  @ 56-63
 #endif
     .size   find_first_set_bit, .-find_first_set_bit
+