* doc/md.texi (Machine Constraints): Add PDP-11 constraints.

From-SVN: r166335

2 files changed, 53 insertions, 0 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b47d9e2..54b448b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,9 @@
 2010-11-04  Paul Koning  <ni1d@arrl.net>
 
+	* doc/md.texi (Machine Constraints): Add PDP-11 constraints.
+	
+2010-11-04  Paul Koning  <ni1d@arrl.net>
+
 	* doc/invoke.texi (PDP-11 Options): Delete -msplit, -mno-split.
 
 2010-11-04  Nicola Pero  <nicola.pero@meta-innovation.com>
diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
index 8418564..c9eb053 100644
--- a/gcc/doc/md.texi
+++ b/gcc/doc/md.texi
@@ -2921,6 +2921,55 @@ A constant in the range of 0 to @minus{}255.
 
 @end table
 
+@item PDP-11---@file{config/pdp11/constraints.md}
+@table @code
+@item a
+Floating point registers AC0 through AC3.  These can be loaded from/to
+memory with a single instruction.
+
+@item d
+Odd numbered general registers (R1, R3, R5).  These are used for 16
+bit multiply operations.
+
+@item f
+Any of the floating point registers (AC0 through AC5).
+
+@item G
+Floating point constant 0.
+
+@item I
+An integer constant that fits in 16 bits.
+
+@item J
+An integer constant whose low order 16 bits are zero.
+
+@item K
+An integer constant that does not meet the constraints for codes
+@samp{I} or @samp{J}.
+
+@item L
+The integer constant 1.
+
+@item M
+The integer constant -1.
+
+@item N
+The integer constant 0.
+
+@item O
+Integer constants -4 through -1 and 1 through 4; shifts by these
+amounts are handled as multiple single-bit shifts rather than a single
+variable-length shift.
+
+@item Q
+A memory reference which requires an additional word (address or
+offset) after the opcode.
+
+@item R
+A memory reference that is encoded within the opcode.
+
+@end table
+
 @item RX---@file{config/rx/constraints.md}
 @table @code
 @item Q