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tcg-ppc: use new return-argument ld/st helpers

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These use a 32-bit load-of-immediate to save a mflr+addi+mtlr sequence.
Tested with a Windows 98 guest (pretty much the most recent thing I
could run on my PPC machine) and kvm-unit-tests's sieve.flat.  The
speed up for sieve.flat is as high as 10% for qemu-system-i386, 25%
(no kidding) for qemu-system-x86_64 on my PowerBook G4.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
This commit is contained in:
Paolo Bonzini 2013-09-05 10:22:09 +02:00 • committed by Richard Henderson
parent 6a11557988
commit 619f90ba62
2 changed files with 21 additions and 24 deletions
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4
include/exec/exec-all.h
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@ -324,9 +324,7 @@ extern uintptr_t tci_tb_ptr;
In some implementations, we pass the "logical" return address manually;
in others, we must infer the logical return from the true return. */
#if defined(CONFIG_QEMU_LDST_OPTIMIZATION) && defined(CONFIG_SOFTMMU)
# if defined (_ARCH_PPC) && !defined (_ARCH_PPC64)
# define GETRA_LDST(RA) (*(int32_t *)((RA) - 4))
# elif defined(__arm__)
# if defined(__arm__)
/* We define two insns between the return address and the branch back to
straight-line. Find and decode that branch insn. */
# define GETRA_LDST(RA) tcg_getra_ldst(RA)