as: s390 Options
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1 9.40.1 Options
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1 The following table lists all available s390 specific options:
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1 '-m31 | -m64'
1 Select 31- or 64-bit ABI implying a word size of 32- or 64-bit.
1
1 These options are only available with the ELF object file format,
1 and require that the necessary BFD support has been included (on a
1 31-bit platform you must add -enable-64-bit-bfd on the call to the
1 configure script to enable 64-bit usage and use s390x as target
1 platform).
1
1 '-mesa | -mzarch'
1 Select the architecture mode, either the Enterprise System
1 Architecture (esa) mode or the z/Architecture mode (zarch).
1
1 The 64-bit instructions are only available with the z/Architecture
1 mode. The combination of '-m64' and '-mesa' results in a warning
1 message.
1
1 '-march=CPU'
1 This option specifies the target processor. The following
1 processor names are recognized: 'g5' (or 'arch3'), 'g6', 'z900' (or
1 'arch5'), 'z990' (or 'arch6'), 'z9-109', 'z9-ec' (or 'arch7'),
1 'z10' (or 'arch8'), 'z196' (or 'arch9'), 'zEC12' (or 'arch10'),
1 'z13' (or 'arch11'), 'z14' (or 'arch12'), 'z15' (or 'arch13'), and
1 'z16' (or 'arch14').
1
1 Assembling an instruction that is not supported on the target
1 processor results in an error message.
1
1 The processor names starting with 'arch' refer to the edition
1 number in the Principle of Operations manual. They can be used as
1 alternate processor names and have been added for compatibility
1 with the IBM XL compiler.
1
1 'arch3', 'g5' and 'g6' cannot be used with the '-mzarch' option
1 since the z/Architecture mode is not supported on these processor
1 levels.
1
1 There is no 'arch4' option supported. 'arch4' matches
1 '-march=arch5 -mesa'.
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1 '-mregnames'
1 Allow symbolic names for registers.
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1 '-mno-regnames'
1 Do not allow symbolic names for registers.
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1 '-mwarn-areg-zero'
1 Warn whenever the operand for a base or index register has been
1 specified but evaluates to zero. This can indicate the misuse of
1 general purpose register 0 as an address register.
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