Merge branches/TCHAIN from r12476 (its creation point) into trunk.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12517 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/coregrind/pub_core_transtab_asm.h b/coregrind/pub_core_transtab_asm.h
index 6d43a7a..00adced 100644
--- a/coregrind/pub_core_transtab_asm.h
+++ b/coregrind/pub_core_transtab_asm.h
@@ -42,8 +42,9 @@
ever be used. So instead the function is '(address >>u
2)[VG_TT_FAST_BITS-1 : 0]' on those targets.
- On ARM we do like ppc32/ppc64, although that will have to be
- revisited when we come to implement Thumb.
+ On ARM we shift by 1, since Thumb insns can be of size 2, hence to
+ minimise collisions and maximise cache utilisation we need to take
+ into account all but the least significant bit.
On s390x the rightmost bit of an instruction address is zero.
For best table utilization shift the address to the right by 1 bit. */