diff options
| -rw-r--r-- | lib/Target/SystemZ/README.txt | 20 |
1 files changed, 5 insertions, 15 deletions
diff --git a/lib/Target/SystemZ/README.txt b/lib/Target/SystemZ/README.txt index 2782b63..563513b 100644 --- a/lib/Target/SystemZ/README.txt +++ b/lib/Target/SystemZ/README.txt @@ -47,7 +47,7 @@ There is no scheduling support. -- -We don't use the BRANCH ON COUNT or BRANCH ON INDEX families of instruction. +We don't use the BRANCH ON INDEX instructions. -- @@ -56,18 +56,7 @@ and conditional returns. -- -We don't use the condition code results of anything except comparisons. - -Implementing this may need something more finely grained than the z_cmp -and z_ucmp that we have now. It might (or might not) also be useful to -have a mask of "don't care" values in conditional branches. For example, -integer comparisons never set CC to 3, so the bottom bit of the CC mask -isn't particularly relevant. JNLH and JE are equally good for testing -equality after an integer comparison, etc. - --- - -We don't use the LOAD AND TEST or TEST DATA CLASS instructions. +We don't use the TEST DATA CLASS instructions. -- @@ -77,9 +66,10 @@ condition codes. For example, we could use LCDFR instead of LCDBR. -- -We don't optimize block memory operations. +We don't optimize block memory operations, except using single MVCs +for memcpy. -It's definitely worth using things like MVC, CLC, NC, XC and OC with +It's definitely worth using things like CLC, NC, XC and OC with constant lengths. MVCIN may be worthwhile too. We should probably implement things like memcpy using MVC with EXECUTE. |