s390: Print base register 0 as "0" in disassembly
Base and index register 0 have no effect in address computation: "A value of zero in the B [base] or X [index] field specifies that no base or index is to be applied, and, thus, general register 0 cannot be designated as containing a base address or index." IBM z/Architecture Principles of Operation [1], chapter "Organization", section "General Registers". Index register 0 is omitted in the s390 disassembly. Base register 0 is omitted in D(B), D(L,B) and D(X,B) - the latter only if the index register is zero. To make it more apparent print base register 0 as "0" instead of "%r0", whenever it would still be printed in the disassembly. [1]: IBM z/Architecture Principles of Operation, SA22-7832-13, https://publibfp.dhe.ibm.com/epubs/pdf/a227832d.pdf opcodes/ * s390-dis.c: Print base register 0 as "0" in disassembly. binutils/ * NEWS: Mention base register 0 now being printed as "0" in s390 disassembly. gas/ * testsuite/gas/s390/zarch-base-index-0.d: Update test case output verification patterns to accept "0" as base base register due to disassembler output format change. * gas/testsuite/gas/s390/zarch-omitted-base-index.d: Likewise. Reviewed-by:Andreas Krebbel <krebbel@linux.ibm.com> Signed-off-by:
Jens Remus <jremus@linux.ibm.com>
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