s390: Document syntax to omit base register operand

Document the s390-specific assembler syntax introduced by commit
aacf780bca29 ("s390: Allow to explicitly omit base register operand in
assembly") to omit the base register operand B in D(X,B) and D(L,B) by
coding D(X,) and D(L,).

While at it document the alternative syntax to omit the index register
operand X in D(X,B) by coding D(,B) instead of D(B).

gas/
	* doc/c-s390.texi (s390 Operands): Document syntax to omit base
	register operand.

Fixes: aacf780bca29 ("s390: Allow to explicitly omit base register operand in assembly")
Signed-off-by: Jens Remus <jremus@linux.ibm.com>

diff --git a/gas/doc/c-s390.texi b/gas/doc/c-s390.texi
index f73dfdeae608f9aca06415bfa25e527b88947bc4..cd0dc7be2585fa08599d2e510b7e6960e5dfbf59 100644 (file)
--- a/gas/doc/c-s390.texi
+++ b/gas/doc/c-s390.texi
@@ -300,10 +300,11 @@ field. The notation changes as follows:
 @display
 @multitable @columnfractions 0.30 0.30
 @headitem full notation @tab short notation
-@item Dn(0,Bn) @tab Dn(Bn)
+@item Dn(Xn,0) @tab Dn(Xn,)
+@item Dn(0,Bn) @tab Dn(,Bn) or Dn(Bn)
 @item Dn(0,0) @tab Dn
 @item Dn(0) @tab Dn
-@item Dn(Ln,0) @tab Dn(Ln)
+@item Dn(Ln,0) @tab Dn(Ln,) or Dn(Ln)
 @end multitable
 @end display