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Article #51730Re: Global Registers Question
From: Bruno Haible
Date: Sun, 04 Apr 1993 15:00
Date: Sun, 04 Apr 1993 15:00
20 lines
1706 bytes
1706 bytes
John Garnett asks:
> What I'd like
> to know are appropriate values for REG on different architectures.
> That is, which registers can I safely use on the various SPARCs,
> hp's, decstations, etc (just need to know two or three regs for
> each architecture).
Look into the machine description for the specific CPU, especially
the definitions of FIXED_REGISTERS and CALL_USED_REGISTERS. Take any
register that has a 0 in both of these arrays, and which can hold values
of the desired type.
On Sparc, you can take %g7, %g6, %g5. (gcc emits a warning that these
registers may be used as temporary registers, but for me it works.)
On HPPA, it's %r5 to %r18. On 680x0, take a4 and a3. (a6 is the static
chain register, and a5 is used by some operating systems.)
Bruno Haible
haible@ma2s2.mathematik.uni-karlsruhe.de
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 11318c,1fcd76eac4049c43 X-Google-Attributes: gid11318c,public X-Google-ArrivalTime: 1993-04-04 08:00:33 PST Path: arc1-ca.pugleaf.net!gmd.de!Germany.EU.net!ira.uka.de!rz.uni-karlsruhe.de!ma2s2!haible From: haible@ma2s2.uucp (Bruno Haible) Newsgroups: gnu.gcc.help Subject: Re: Global Registers Question Date: 4 Apr 1993 15:00:09 GMT Organization: University of Karlsruhe, Germany Lines: 20 Sender: haible@ma2s2.mathematik.uni-karlsruhe.de Message-ID: <1pmt5p$sse@nz12.rz.uni-karlsruhe.de> References: <1pjeghINNfg1@geraldo.cc.utexas.edu> NNTP-Posting-Host: ma2s2.mathematik.uni-karlsruhe.de Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Summary: the non-call-used registers Keywords: gcc, register, asm, a5, global variable